electrical engineering design manual

Electrical Engineering

DESIGN MANUAL

Revised as of 2021

Section DM

TABLE OF CONTENTS

Section DM 1

INTRODUCTION

INTRODUCTION

REVISION NO. 1

DATE: 03-29-2021

DESIGN MANUAL

DM 1 PAGE 1 OF 6

SECTION DM 1: INTRODUCTION

TABLE OF CONTENTS No. TITLE PAGE 1.0 INTRODUCTION 3 2.0 MANUAL FORMAT 5 3.0 DESCRIPTION OF SECTIONS 5

3.1 Feeder Systems (Section DM 2) 5

3.2 Commercial/Industrial Subsystems (Section DM 3) 5

3.3 Residential Subsystems (Section DM 4) 5

3.4 Transformer Loading (Section DM 5) 5

3.5 Voltage Drop, Flicker, and Short Circuit Duty (Section DM 6) 5

3.6 Cable Pulling Tension Calculations and Terminations (Section DM 7) 5 3.7 Overhead Systems (Section DM8) 6

3.8 Guying Poles in Overhead Systems (Section DM 9) 6

3.9 Typical Formulas (Section DM 10) 6

3.10 Underground Structure and Equipment Application Guidelines (Section DM 11) 6

3.11 Forms (Section DM 12) 6

3.12 Glossary (Section DM 13) 6

REVISION NO. 1

INTRODUCTION

DATE: 03-29-2021

DESIGN MANUAL

DM 1 PAGE 2 OF 6

FIGURES No. TITLE PAGE 1-1 Relationship between Feeder and Subsystems 4

INTRODUCTION

REVISION NO. 1

DATE: 03-29-2021

DESIGN MANUAL

DM 1 PAGE 3 OF 6

DM 1: INTRODUCTION 1.0 INTRODUCTION The Design Manual is intended to promote consistency in design and as a means for training new designers. It outlines the design criteria and guidelines for the City of Anaheim electric system. The contents of this manual are to be guidelines for design. If the contents of this manual are found to be in conflict with Electrical Division Construction Standards, designers should bring the discrepancy to the attention of their supervisor. The uniform application of this design manual will assist with implementation of consistent design practices among designers. Adoption of these design practices will help the City of Anaheim to maintain system integrity, reliability, and operability. This manual does not cover construction details (see Electrical Division Construction Standards), Rules and Regulations (see Rates, Rules and Regulations), Codes (see National Electrical Code, the State of California General Orders 95 and 128, and California Code of Regulations, Title 8), Material Specifications (see Specifications), and Electric Utility Service Equipment Requirements (see EUSERC Manual). In this manual, a distinction is made between "feeder" and "subsystem". The example in Figure 1-1: Relationship between Feeder and Subsystems identifies that relationship.

REVISION NO. 1

INTRODUCTION

DATE: 03-29-2021

DESIGN MANUAL

DM 1 PAGE 4 OF 6

Figure 1-1: Relationship between Feeder and Subsystems

NOTES:

1. Three Phase 12 kV, Section DM 3: Commercial/Industrial Subsystem 2. Single Phase 6.9 kV, Section DM 4: Residential Subsystem

INTRODUCTION

REVISION NO. 1

DATE: 03-29-2021

DESIGN MANUAL

DM 1 PAGE 5 OF 6

2.0 MANUAL FORMAT This manual is organized in a design process format rather than a reference document. 3.0 DESCRIPTION OF SECTIONS This manual consists of this Introduction followed by twelve additional sections as described below:

3.1 Feeder Systems (Section DM 2)

This section provides the design criteria of the distribution system that serve as the “mainline” portion of the circuit that forms the 12 kV network interconnecting circuits and substations of the system. In the past, smaller size cables and conductors were used and still exist, but all new designs for feeder systems shall be 1,000 kcmil cables for underground and 336/653 ACSR for overhead, unless otherwise directed.

3.2 Commercial/Industrial (C/I) Subsystems (Section DM 3)

This section provides the design criteria for the majority of commercial/industrial installations. Some of the design criteria included in this section are a methodology for demand estimating, resulting in estimated loads that are close to those actually experienced which allows for better transformer sizing. These criteria consider the effect of energy efficient construction and equipment technology.

3.3 Residential Subsystems (Section DM 4)

This section provides the design criteria for new residential developments as well as existing. Some of the significant design guidelines included in this section are the selection of transformers such as padmount surface operable, Buried Underground Residential Distribution (BURD) transformers or overhead transformers

3.4 Transformer Loading (Section DM 5)

This section provides loading criteria for transformers serving commercial/industrial and residential loads.

3.5 Voltage Drop, Flicker, and Short Circuit Duty (Section DM 6)

This section provides the scope and criteria for voltage drop and flicker for commercial/industrial and residential customers. The general formula for calculations and concept of voltage drop constant are included as well. Short circuit duty for single phase and three phase customers are also provided in this section.

3.6 Cable Pulling Tension Calculations and Terminations (Section DM 7)

This section provides the scope and criteria for pulling cables in conduits, as well as general guidelines for terminations. Maximum allowable pulling tensions and calculations for maximum stresses on cables while

REVISION NO. 1

INTRODUCTION

DATE: 03-29-2021

DESIGN MANUAL

DM 1 PAGE 6 OF 6

pulling are discussed. Formulas for calculation of pulling tension and sidewall pressure and examples are provided.

3.7 Overhead Systems (Section DM 8)

This section establishes design criteria to be used in designing overhead systems. Specific criteria are given to provide for the design of an overhead pole line, reconductoring and performing wind loading calculations.

3.8 Guying Poles in Overhead Systems (Section DM 9)

This section provides the scope and criteria for guying poles in overhead systems. Different methods of guying in different circumstances are presented and related tables and guidelines for selecting the correct size of guy wires are provided as well.

3.9 Typical Formulas (Section DM 10)

This section contains several useful engineering formulas and factors for Electric Systems Design.

3.10 Underground Structure and Equipment Application Guidelines (Section DM 11)

This section provides the criteria to be used in selecting the proper size structure and equipment that will adequately accommodate new installations and also to help determine equipment that may be installed in existing structures.

3.11 Forms (Section DM 12)

This section contains sample templates of forms and letters that designers need to use in the design process.

3.12 Glossary (Section DM 13)

This section contains a glossary including the definition of key terms used in this manual.

Section DM 2

FEEDER SYSTEMS

FEEDER SYSTEMS

REVISION NO. 1

DATE: 03-29-2021

DESIGN MANUAL

DM 2 PAGE 1 OF 9

SECTION DM 2: FEEDER SYSTEMS

TABLE OF CONTENTS No. TITLE PAGE 1.0 SCOPE 3 2.0 DESIGN CONCEPT 3 3.0 DESIGN CRITERIA 4

3.1 Cable Selection 4

3.2 Structure Selection 4

3.3 Switch Selection 6

3.4 Circuit Ties 9

REVISION NO. 1

FEEDER SYSTEMS

DATE: 03-29-2021

DESIGN MANUAL

DM 2 PAGE 2 OF 9

FIGURES No. TITLE PAGE 2-1 Padmount Switch Applications – PMC 7 2-2 Padmount Switch Applications – PMV 7 2-3 Subsurface Switch Applications – UDS 8

FEEDER SYSTEMS

REVISION NO. 1

DATE: 03-29-2021

DESIGN MANUAL

DM 2 PAGE 3 OF 9

DM 2: FEEDER SYSTEMS 1.0 SCOPE This section establishes the design criteria to be used in designing feeder systems. The feeder system is the "mainline" portion of the circuitry that forms the 12 kV network interconnecting circuits and substations. The feeder system is designed with 1,000 kcmil Copper and/or Aluminum EPR cables on underground circuits and 336 to 653 ACSR on overhead circuits, unless otherwise directed. The need to design a new feeder system can be initiated through activities such as circuit planning, underground conversion projects, large new developments, etc. Appropriate design criteria should be applied to arrive at a reliable and economical design. 2.0 DESIGN CONCEPT The feeder system design criteria apply to planning of a new distribution circuit, undergrounding of sections of an existing overhead feeder, or adding a new section for extension of an existing feeder. It also applies to rearrangement of an existing feeder section. The design of feeder systems should result in capital expenditures being deferred when the actual need for equipment is not required for five years and conduits/substructures are not required for ten years. The layout and configuration of the design should additionally consider the anticipated customer load. A feeder should be planned for peak load conditions. The designer should try to optimize the number and location of switches and subsystem connections to the feeder by using the following strategies:

A. Plan the strategic location of circuit ties to provide flexibility to perform required switching (planned and emergency) in coordination with System Planning and Electric Operations groups. The intent is to maximize electric reliability while minimizing overall capital expenditures.

B. Loading on feeder circuits is to be established during the design process, and in coordination

with System Planning. The ultimate planned peak circuit loading should be approximately 400 Amps per substation feeder. This will make tying between circuits easier in case of an N-1 contingency scenario. Additionally, when designing underground conversions, feeder replacement, or upgrades, designs are to consider circuit balancing, offloading other higher loaded circuits, and other operational criteria.

C. Plan to incorporate padmount switches where easement locations on private property are

feasible, with the consent of the property owner. Where padmount devices are not feasible, plan to install underground subsurface switches, typically in the right-of-way, however, on side streets or right turn lanes whenever applicable, in order to enable field crews to access vaults with slower traffic lanes.

REVISION NO. 1

FEEDER SYSTEMS

DATE: 03-29-2021

DESIGN MANUAL

DM 2 PAGE 4 OF 9

D. As more of Anaheim’s distribution system is being automated, designs should be reviewed for potential inclusion of automation devices in coordination with the System Planning group. Provisions should be allowed for future automation, by stubbing out conduits from vaults, at a minimum.

E. Designs should also take into consideration the aesthetics of the area and any roadway

requirements, in conjunction with the Department of Public Works and the Planning Department. Should other City projects be scheduled for construction, designers will make efforts to coordinate schedules so as to minimize disruption to the area residents and businesses.

3.0 DESIGN CRITERIA

3.1 Cable Selection

Underground feeder systems are to be designed with 1,000 kcmil AL cables for the entire length of the feeder with the exception of substation cable getaways. Substation cable getaways is designed with 1,000 kcmil CU cables from the substation breaker to the first splice or switch of the feeder as directed by the System Planning group. Deviations from these design criteria are to be brought forward to the designer’s supervisor for review and approval. There are existing locations with smaller size cable, including 4/0 and 750 kcmil and should be evaluated for replacement with 1,000 kcmil so as to limit bottlenecks in the feeder system. In some cases, substructure and conduit size limitation may not allow for replacement with 1,000 kcmil cable, and should be reviewed with the designer’s supervisor and System Planning to determine a plan for future substructure replacement.

Overhead feeder systems are designed with 336 ACSR conductors or 653 ACSR conductors, and the more typical application of overhead conductors in Anaheim is for reconductoring projects. Use of overhead construction for new feeders are only authorized in situations where underground is not feasible, and may only be authorized by the designer’s supervisor in coordination with System Planning. The size of the overhead conductors is determined after a load study is completed. Factors that affect the conductor size include but not limited to the ultimate projected load density for future substation or circuit plans and emergency circuit operating plans. If the System Planning study finds 336 ACSR conductors to be undersized for the anticipated load in five years, use 653 ACSR conductors. All overhead designs require pole loading calculations to be performed.

3.2 Structure Selection

Design and selection of substructure systems and materials shall accommodate design ampacity including derating factor.

A. Structure Type and Size

Tub-type structures are standard for vaults and surface-operable enclosures used for feeders and subsystems.

FEEDER SYSTEMS

REVISION NO. 1

DATE: 03-29-2021

DESIGN MANUAL

DM 2 PAGE 5 OF 9

Padmounted or surface-operable equipment and structures should be utilized where conditions permit.

Structures selected should be the smallest/least expensive structures that will accommodate the anticipated ten-year need, so as to minimize roadway construction. Section DM 6 provides tables that should be used to determine the maximum cable/equipment that may be installed in various structure types and sizes.

B. Structure Spacing and Location

In consideration of maximum reel length of 1,000 kcmil triplex cable used for Anaheim feeder systems, which is 1,200 feet, and the cable length needed for risers and vaults, the maximum structure spacing distance should be limited to 1,000 feet. Within that limitation, structures should be spaced as far as cable pulling lengths will allow (per Section DM 7) and still achieve lowest-cost alternative to meet service to load design requirements.

The preferred location for structures is in non-traffic areas with good vehicular access, such as side streets. The second choice would be in light traffic areas, such as right turn lanes for vaults. Full traffic locations are least desirable, such as major intersections.

In all cases, consideration must be given to the following items when determining structure locations:

1. Clearance from other utilities' substructures.

2. Traffic patterns and traffic control requirements.

3. Visibility for vehicles when using padmount equipment.

4. Aesthetics in relation to development plans (See Utility Equipment Screening).

C. Riser Cable Runs

It is typically most economical to maximize the distance between the riser pole and the first structure. Pulling structures should be eliminated when possible.

D. Duct Bank Planning

The standard duct bank design for 12 kV is 6-6” conduits for power circuits and 2-4” conduits for communication circuits. A maximum of three 12 kV feeders are installed in any one duct bank, and is typical along major roadways so as to minimize future roadway construction and maximize space for other utilities.

The preferred location for conduits is in parallel to curbs. The existing location of other utility facilities must be researched and plotted on a base map to properly plan electric duct banks.

REVISION NO. 1

FEEDER SYSTEMS

DATE: 03-29-2021

DESIGN MANUAL

DM 2 PAGE 6 OF 9

Normally, ten feet of separation is required between transmission and distribution conduits, and five feet of separate is optimal between electric and wet utilities. Twelve inches is the minimum separation requirement to other utilities in an underground conduit installation for parallel runs and crossings.

E. Joint Trench

Joint trench construction along public roadways (with dry utilities such as telephone, CATV, or other utilities) should be planned according to good engineering practices and G.O. 128 clearance requirements. Joint trench provides a means to share trenching and paving costs among participants. Joint trenching with gas or other fuel lines is not allowed.

3.3 Switch Selection

The following feeder switches can be used in order of preference:

A. Padmount switches are the preferred type of installation due to ease of maintenance,

installation, and operability. However, designers should carefully review the location of padmount devices to ensure that they do not conflict with the design of the roadway without some type of device screening. PMC switches with stainless steel cabinets are standard.

1. PMC – Padmounted Cabinet (PMC) is the preferred type of padmount switch since it does

not use SF6 gas as the insulating medium or vacuum for fault interrupting medium (VFI), and is less costly to maintain. But the easement and clearance requirements around the PMC switch may be an impediment since access to PMC for operation and maintenance is required on opposite sides of the equipment. If easement and clearance requirements cannot be met, a Padmounted Vault (PMV) would be a more appropriate design. Figure 2-1: Padmount Switch Applications – PMC shows a typical application for a PMC.

FEEDER SYSTEMS

REVISION NO. 1

DATE: 03-29-2021

DESIGN MANUAL

DM 2 PAGE 7 OF 9

Figure 2-1: Padmount Switch Applications – PMC

2. PMV (VFI) – Padmounted Vault (PMV) with SF6 gas as the insulating medium and vacuum for fault interrupting medium (VFI) is used if easement and clearance requirements around the PMC switch may be an impediment. The PMV has its main access on one side only and requires a smaller easement and less clearance around it. Figure 2-2: Padmount Switch Applications – PMV shows a typical application for a PMV.

Figure 2-2: Padmount Switch Applications – PMV

REVISION NO. 1

FEEDER SYSTEMS

DATE: 03-29-2021

DESIGN MANUAL

DM 2 PAGE 8 OF 9

B. Sub-surface Switches

1. UDS – Solid Dielectric Switch (UDS) has the highest upfront cost of all the above three options, and is the most time consuming to operate and maintain since it requires accessing underground vaults. This option is used only when padmount switches cannot or should not be used due to restriction by the Planning Department, for example in the Anaheim Resort Area. Figure 2-3: Subsurface Switch Applications – UDS shows a typical application for a UDS.

2. Anaheim has existing subsurface gas switches: Gas Switch Enclosures (GSE) and

Vaultmount Gas Switch (VGS) in existing vaults. GSE and VGS switches are not to be used in new designs, unless otherwise directed.

Figure 2-3: Subsurface Switch Applications – UDS

C. Overhead Switches

1. The Omni-Rupter overhead load break switch is the standard for new overhead switch installations as approved in the construction standard where switching can be conducted from the overhead system. The Omni-Rupter overhead load break switch may also be used on riser poles to switch underground systems in place of underground switches.

Circuits shall be planned so that the loading of individual cables in a duct bank will not exceed the planned loading limits. Circuits shall also be planned so as to support the load shifts required during contingencies due to loss of one substation transformer (B-bank) without exceeding the emergency operating ratings.

FEEDER SYSTEMS

REVISION NO. 1

DATE: 03-29-2021

DESIGN MANUAL

DM 2 PAGE 9 OF 9

3.4 Circuit Ties

Feeder designs, including circuit ties, must be site-specific and designed in conjunction with a contingency load transfer plan. In most cases, three properly located circuit ties are sufficient to satisfy required planned and emergency operations (N-2 condition). However, geographic conditions (i.e., mountains, flood control channels, freeways, etc.), loading, distance, or operating constraints (i.e., fire areas, PE equipment, protection requirements, etc.) may require circuits to be designed with more or less than three circuit ties.

These ties should allow load transfers between circuits and maintain circuit loadings that are below the relay minimum trip settings and emergency cable loading limits of the feeder.

The number of ties with circuits out of the same substation versus circuits out of another substation must be considered in order to satisfy the criteria for load transfers during loss of one substation transformer (B-bank). When circuit ties are designed, the locations of circuit ties will need to be coordinated and designed in coordination with System Planning and Electric Operations, and should consider automation as well as the location of a mid-point switch to restore customers by quickly isolating half the load on a circuit outage.

Section DM 3

COMMERCIAL/INDUSTRIAL SUBSYSTEMS


REVISION NO. 0

DATE: 03-07-2013

DESIGN MANUAL

DM 3 PAGE 1 OF 21

SECTION DM 3: COMMERCIAL/INDUSTRIAL SUBSYSTEMS


3.1 Demand Estimating 3

3.2 Service Points 8

3.3 Equipment Selection 10

3.4 Cable Selection 11

3.5 Substructure Selection 13

3.6 Feeder Interface 15

3.7 Subsystem Design 15 3.8 Padmount Transformer Locations 16 3.9 Medium Voltage Primary Metering 17 4.0 SAMPLE CALCULATIONS 20 4.1 Estimating Demand Using Customer Plans and Connected Load (Method One) 20 4.1 Estimating Demand Using Square Footage (Method Two) 20 4.3 Estimating Demand Using Historical Information (Method Three) 21

REVISION NO. 0


DATE: 03-07-2013

DESIGN MANUAL

DM 3 PAGE 2 OF 21

TABLES No. TITLE PAGE 3-1 Large Load Demand Factors 4 3-2 Demand by Type of Occupancy 5 3-3 Building Type Descriptions 6 3-4 Primary Cable Ampacity 12 3-5 Secondary/Service Cable Ampacity 13 3-6 Number of Conduit Runs based on Pull Section Size 14

FIGURES No. TITLE PAGE 3-1 Clearance Requirement from Buildings for Padmounted Transformers 17 3-2 Typical Single Line Diagram for Medium Voltage Primary Metering 19


REVISION NO. 0

DATE: 03-07-2013

DESIGN MANUAL

DM 3 PAGE 3 OF 21

DM 3: COMMERCIAL/INDUSTRIAL SUBSYSTEMS 1.0 SCOPE This section provides the criteria for designing commercial/industrial (C/I) underground distribution facilities. This includes demand estimating, service points, transformer selection, cable selection, substructure selection, feeder interface, subsystem design, padmount transformer locations and medium voltage primary meter. 2.0 DESIGN CONCEPT C/I subsystems are generally designed utilizing 1/0, or 4/0 cable, 200 Amp components, and pad mounted equipment coming off the feeder. Subsystems are normally served from a switch position rated at 200 Amp. Facility sizing shall comply with the following loading criteria:

Item Loading Criteria

Substructures Design ampacity including derating factor

Primary Cable Anticipated demand load in 5 years

Transformers Expected initial demand plus additional growth in 5 years

Secondary/Service Cable Design ampacity including derating factor, voltage and flicker calculations 3.0 DESIGN CRITERIA

3.1 Demand Estimating

To accurately estimate demand, use the average of three methods outlined below whenever possible. The three methods of demand estimating are as follows:

A. Estimate Demand Based on Customer Plans and Connected Load

B. Estimate Demand Based on Demand Per Square Foot

C. Estimate Demand Based on Historical Demand of Similar Customer

Method “1” is the preferred method when the information is available. Methods “2” and “3” are based on historical demands. If the difference of either Method “2” or Method “3” is over 25 percent compared to Method “1”, that method can be omitted in the calculation and the average of the two remaining methods shall be used.

REVISION NO. 0


DATE: 03-07-2013

DESIGN MANUAL

DM 3 PAGE 4 OF 21

A. Method “1”, Estimate Demand Based on Customer Plans and Connected Load

Obtain the electrical plans and panel schedules from the customer or electrical contractor. A written commitment should be obtained from the customer requesting the desired service voltage and indicating the connected load.

With industrial customers, it is particularly important to determine the types of operation, hours of operation, and how they plan to use their equipment.

Use a 50% demand factor for total connected load (air conditioning units, lighting, receptacles, cooking, etc.) excluding large loads such as motors and welders. Table 3-1: Large Load Demand Factors provides demand factors to be used for various large loads of C/I loads. Use these demand factors with the customer's load schedule to determine the estimated demand.

Table 3-1: Large Load Demand Factors

Type of Load Demand Factor

Motors

100% of largest unit __% of balance*

Arc Welders 100% of largest unit 10% of balance

Induction/Resistance Heating

100% of largest unit 50% of balance

Injection Molding 100% of largest unit 50% of balance

* Balance of motor loads will be dependent on quantity and nature of operation

B. Method “2”, Estimate Demand Based on Demand Per Square Foot

Table 3-2: Demand by Type of Occupancy provides typical demands in volt amperes per square foot for different types of occupancies. Also included are typical power factors and load factors for each type of occupancy. Use the values from table for the applicable type of occupancy and square footage to determine the estimated demand. Formula: kVA = (sq. ft. * VA/sq. ft.)/1,000.


REVISION NO. 0

DATE: 03-07-2013

DESIGN MANUAL

DM 3 PAGE 5 OF 21

Table 3-2: Demand by Type of Occupancy (In Volt Amperes per Square Foot)

Building Type

Number*** Building Type Power

Factor Load

Factor Average Peak

Demand 1 Large Office Building (>30K sq. ft.) 85 44 4.7 2 Small Office Building (<30K sq. ft.) 86 34 8.5 3 Restaurants (<3K sq. ft.) 88 44 20.5 4 Restaurants (>3K sq. ft.) 87 49 14.5 5 Large Retail (>30K sq. ft.) 89 49 4.2 6 Small Retail (<30K sq. ft.) 90 37 8.6 7 Large Food Store (>30K sq. ft.) 89 79 10 8 Small Food Store (<30K sq. ft.) 88 58 13.9 9 Large Electronic Retail (>30K sq. ft.) 91 59 7.6

10 Small Electronic Retail (<30K sq. ft.) 90 54 10.7 11 Refrigerated Wholesale 79 54 17.8 12 Non-refrigerated with A/C Wholesale 83 34 5.1 13 Non-refrigerated, non A/C Wholesale 85 28 0.7 14 Elem. and Sec. School 79 25 10.1 15 Colleges and Universities 84 35 6.2 16 Hospitals 85 55 6.7 17 Health Clinics 85 45 6.8 18 Hotels and Motels 86 45 4.8 19 Auto Repair Shops 81 28 6.7 20 Misc. Repair 80 30 7.3 21 Movie Theatres 93 37 12.7 22 Bowling Alleys 83 48 6.5 23 U.S. Post Offices 82 47 6.7 24 Meat Packing 82 48 15.7 25 Fruit and Vegetable Processing 78 40 5.4 26 Bakery Products 74 48 10 27 Apparel Manufacturing 82 31 6 28 Furniture Manufacturing 77 33 8.4 29 Paper Products 75 46 7.5 30 Printing/Publishing 81 31 9.1 31 Plastic Products 85* 46 11.4* 32 Metal Fabrication 77 37 9.4 33 Telephone Communication Center 85* 61 11.4*

* Power factor estimated at 85%, kVA determined from actual kW/0.85

** Table based off Southern California Edison within the same climate zone of Anaheim. *** For building type description, see Table 3-3: Building Type Descriptions.

REVISION NO. 0


DATE: 03-07-2013

DESIGN MANUAL

DM 3 PAGE 6 OF 21

Table 3-3: Building Type Descriptions Table 3-3: Building Type Descriptions lists the Standard Industrial Classification (SIC) grouping for each building type presented in Table 3-2: Demand by Type of Occupancy. In general, this grouping is consistent with California Energy Commission's aggregations of groups of SIC codes into building type.

Building Type

Number

Building Type Building Description

Commercial 1 Large Office Building

(>30K sq. ft.) Depository Institutions, Insurance Carriers/Agents, Real Estate, Business Services, Medical Clinics/Offices, Legal Services, Social Services, Business/Labor/Political Organizations, Courts

2 Small Office Building (<30K sq. ft.)

Same as above

3 Restaurants (<3K sq. ft.) Eating and Drinking Places 4 Restaurants (>3K sq. ft.) Same as above 5 Large Retail (>30K sq. ft.) Building Materials and Garden Supplies, Department Stores, Auto

Dealers, Clothing Stores, Furniture/Appliance/Home Furnishing Stores, Misc. Retail (Drug, Sporting Goods, Bicycle, Stationary, Gift)

6 Small Retail (<30K sq. ft.) Same as above 7 Large Food Store (>30K

sq. ft.) Grocery, Dairy Products, Fruit and Vegetable, Meat and Fish, Retail Bakeries, Liquor Stores

8 Small Food Store (<30K sq. ft.)

Same as above “7-11,” “Stop-N-Go”

9 Large Electronic Retail (>30K sq. ft.)

Electronic, Computer, Appliance

10 Small Electronic Retail (<30K sq. ft.)

Electronic, Computer, Appliance

11 Refrigerated Warehouse Refrigerated Warehousing and Storage, Packaged Frozen Foods, Dairy Products, Poultry Products, Fish and Seafood, Meats and Meat Products, Fresh Fruits and Vegetables

12 Non-refrigerated With A/C Warehouse

Local Trucking With Storage, Public Warehousing and Storage, Wholesale Trade–Durable Goods

13 Non-refrigerated, Non-A/C Warehouse

Motor/Vehicle/Parts/Supplies, Tires, Furniture, Lumber, Hardware

14 Elementary and Secondary Schools

Elementary and Secondary Schools, Day Care Services

15 Colleges and Universities Colleges and Universities, Vocational Schools, Schools and Educational Services

16 Hospitals Hospitals (Surgical / General / Psychiatric), Nursing and Personal Care Facilities

17 Health Clinics Medical and Dental Laboratories, Outpatient Clinics 18 Hotels and Motels Hotels and Motels


REVISION NO. 0

DATE: 03-07-2013

DESIGN MANUAL

DM 3 PAGE 7 OF 21

19 Auto Repair Shops Auto Body, Glass, Exhaust, Paint, Tire, Transmission, and Repair Services

20 Miscellaneous Repair Electrical Appliance Repair (Radio, Television, Refrigerator), Re-upholstery, Watch and Clock

21 Movie Theaters Indoor Movie Theaters 22 Bowling Alleys Bowling Alleys 23 U.S. Post Offices U.S. Postal Service

Industrial 24 Meat Packing Meat Packing Plants, Sausages and Other Prepared Meats, Poultry

Slaughtering and Processing 25 Fruit and Vegetable

Processing Preserved, Canned, Dehydrated, Pickles, Sauces, Salad Dressings, Frozen Fruits and Vegetables

26 Bakery Products Bread, Cake, Cookies, Frozen Bakery Products (Except Bread) 27 Apparel Manufacturing Clothes, Hats, Belts, fur, Leather, Curtains 28 Furniture Manufacturing Wood and Metal Household and Office Furniture, Mattresses and

Bedsprings, Wood TV Cabinet 29 Paper Products Containers, Boxes, Cans, Drums, Bags 30 Printing/Publishing Newspapers, Periodicals, Books, Greeting Cards, Typesetting 31 Plastic Products Plastic Films and Sheets, Laminated, Shapes, Pipe, Bottles, Foam 32 Metal Fabrication Cans, Shipping Containers, Barrels, Hardware, Doors, Sheet Metal,

Screws, Bolts, Nuts, Washers, Stampings, Forgings, Springs 33 Telephone

Communication Center Telephone Communications and Switching Center

REVISION NO. 0


DATE: 03-07-2013

DESIGN MANUAL

DM 3 PAGE 8 OF 21

C. Method “3”, Estimate Demand Based on Historical Demand of Similar Customer

This method utilizes the demand and billing history records through Anaheim’s Customer Information System (CIS) or customer provided information such as a previous utility bill to determine measured maximum demand and power factor for similar existing businesses.

3.2 Service Points

The location of a service point for a C/I development is where the utility enters the customers property and should be minimized to one service point per property. Uniform application of service points will be established using the following criteria:

A. Single Enterprise/Tenant

One or more buildings occupied by a single enterprise/tenant on single premises will be provided one service point at a location determined by the designer to provide access for operations and maintenance. However, additional service points may be provided if it provides Utilities operating convenience, or where provided for in Utilities Electric Rates, Rules, and Regulations. Exceptional cases should be reviewed by the designer and variances approved by the designer’s supervisor, with consideration given to circumstances such as size of the property, size of additional load, customer's operation, and distance to new load as well as size and location of electric utility facilities.

B. Multiple Enterprises/Tenants

One or more buildings in a commercial/industrial development occupied by multiple enterprises/tenants will be provided one service point. Additional service points may be provided for Utilities operating convenience, or where provided for in Electric Rates, Rules, and Regulations.

Regional shopping centers, malls, and other unusually large buildings are typically sufficiently large enough to make additional service points necessary. The designer is to work with the developer’s electrical engineer to determine service points based upon the building configuration and layout of electrical service. Voltage drop, service type/voltage, and transformer utilization will be considered to establish service points consistent with good engineering practices.

C. Service Voltages

The applicable service voltages shall be requested by the customer, subject to availability for any of the service points, taking into consideration the customer's load and use characteristics. All terminating enclosures for services for each of the types and voltage classes of load to be served shall normally be grouped at one location.

The distribution service voltages available to customers are: 120V, 120/240V, 120/208V, 277/480V, and 12 kV. In cases where primary 12 kV service is insufficient for the size and type of load, the designer is to review the option of service at 69 kV in conjunction with the designer’s


REVISION NO. 0

DATE: 03-07-2013

DESIGN MANUAL

DM 3 PAGE 9 OF 21

supervisor and System Planning. In such cases, the consumer substation for a 69 kV service will be sited on the property being served.

D. Utility Operating Convenience

The provision of additional service points for Utility operating convenience refers to the utilization of facilities or practices which contribute to the overall efficiency of Utility's operation. It does not refer to customer convenience or to the use of facilities or adoption of practices required to comply with applicable laws, ordinances, rules or regulations, or similar requirements of public authorities.

As an example, additional service points may be designed if there are multiple transformers in a C/I development that requires looping the subsystem within the property. The additional service points can be justified because of reliability and isolation purposes (operating convenience). The designer is to review the site configuration, layout of equipment, accessibility provisions, development plans for future expansion, etc. with Electric Operations in order to determine the feasibility, cost effectiveness, and ease of operation and maintenance.

E. Added Facilities

Per the Electric Rates, Rules, and Regulations, Added Facilities are considered to be existing, enlarged, or new facilities installed and/or used by the Utility at the customer’s request in addition to, as enlargements of, as alternate to, or in substitution for, the standard facilities which the Utility would normally install or use, and which represent additional costs to the Utility over normally installed facilities. Added Facilities may include, but are not limited to, those facilities necessary to supply Preferred/Emergency Service, data monitoring services, or other non-standard facilities. Except where provided by rate schedule, installation of Added Facilities will be made, provided the type of Added Facilities requested is acceptable to the Utility and the Utility agrees to the installation of the Added Facilities, under the following conditions:

1. The applicant for Added Facilities is also an applicant for permanent electric service or is a

customer for permanent electric service at the same location.

2. The customer will execute a contract prior to the installation of the Added Facilities. In addition to providing for the payment of charges as determined under the appropriated schedule, the contract will provide for one of the following conditions:

a. Prior to the Utility installing Added Facilities, the customer shall pay the Utility for the

Added Facilities and the cost of the installation of such facilities. Thereafter, the customer shall pay a monthly charge for the Added Facilities in an amount determined by the Utility based upon any maintenance as described in the contract.

b. Prior to the Utility installing Added Facilities, the customer shall agree to pay a monthly

charge for the Added Facilities in the amount determined by the Utility based upon the added capital investment, and ongoing maintenance. At its option, the Utility may

REVISION NO. 0


DATE: 03-07-2013

DESIGN MANUAL

DM 3 PAGE 10 OF 21

finance the Added Facilities, and the customer shall be responsible for the associated financing costs.

3. In the event that the Added Facilities are abandoned prior to ten years from the date

service is first rendered from the Added Facilities, the Utility will charge the customer the balance owed on the cost of installed Added Facilities, plus the cost of removal, less the estimated salvage of removable materials.

3.3 Equipment Selection

A. Transformer Type

For serving new loads, installing padmount transformers on the customer's premises outside of the building and easily accessible by vehicle is the preferred design. For projects where space is not available for a padmount transformer, the use of station type transformers in a building may be considered by the designer, in coordination with Electric Operations for accessibility, and with the approval of the designer’s supervisor. An example to this are the transformers installed inside transformer rooms such as in the Platinum Triangle.

For overhead feeds, the designer is to work with the customer to install a padmount transformer on the property, whenever possible. Where the designer determines that overhead service shall be provided, a maximum of (3) 75 kVA overhead transformers may be installed on existing overhead poles with underground service.

B. Transformer Sizing

Transformer capacity shall be installed to supply the sum of all loads to be served. Generally, no diversity should be expected among individual customers in commercial and industrial areas. The transformer selected shall be the smallest that will handle the expected initial demand plus additional growth in 5 years.

Three-phase padmount transformers are available in the following sizes:

75 kVA 500 kVA 1500 kVA 150 kVA 750 kVA 2500 kVA 300 kVA 1000 kVA 3750 kVA Overhead transformers are available in the following sizes: 25 kVA 50 kVA 75 kVA


REVISION NO. 0

DATE: 03-07-2013

DESIGN MANUAL

DM 3 PAGE 11 OF 21

Notes:

1. Transformers with 120/208V secondaries are available from 75 to 750 kVA only. 1,000 kVA transformers with this voltage are available by special order and require no less than six (6) months lead time for ordering.

2. Transformers with 120/240V secondaries are available for 3-phase 4-wire delta services in

underground conversion projects only. They range from 75 to 300 kVA only. 500 kVA transformers with this voltage are available by special order and no less than six (6) months require lead time for ordering.

3. Transformers with 480Y/277V secondaries are available from 75 to 1,500 kVA. 2,500 to

3,750 kVA transformers with this voltage are available by special order and require no less than six (6) months lead time for ordering.

C. Transformer Fusing Requirements

1. All new three phase padmount transformers are supplied with loadbreak switch Bayonet

Fuses and current limiting fuses for single transformer installation. Should the designer encounter a transformer that is non-fused, he/she will replace the transformer with a fused transformer.

2. When three phase padmount transformers are connected from an overhead source, fusing

shall be installed on the riser pole in accordance with the Overhead Construction Standards.

3.4 Cable Selection

A. Primary Cable

Primary cable for a C/I subsystem shall be 1/0 or 4/0 cable in a conventional conduit system. Underground subsystems shall be designed not to exceed 80% loading of cables ampacity. For example, 4/0 cable shall be used for peak loading range between 120 and 200 amperes. 1/0 cable shall be used for peak loading under 120 amperes (peak loading is based on anticipated demand load in five years). In consideration of high fault duty, reliability and isolation purposes, the service point shall not be located before the first switch disconnect of the feeder.

In certain cases, existing installations use direct buried primary cable. If a transformer or a switch needs to be upgraded or replaced, the direct buried primary cable from the transformer or switch to the next switching point will have to be replaced with new conduit and cable.

Per City Ordinance, new line extensions are preferred to be designed underground unless for operation convenience. Therefore, all new Commercial/Industrial Subsystems are to be designed underground, unless otherwise determined.

REVISION NO. 0


DATE: 03-07-2013

DESIGN MANUAL

DM 3 PAGE 12 OF 21

Table 3-4: Primary Cable Ampacity summarizes the different cable sizes available as APU stock items with the corresponding ampacity.

Table 3-4: Primary Cable Ampacity

Conductor Size Copper

(Amps) Aluminum

(Amps) AWG kcmil #2 - - 115 1/0 - - 150 4/0 - 290 225 - 350 385 - - 500 470 - - 750 - 470 - 1000 670 545

* Ampacity values are based on 90˚ Celsius conductor temperature, 20˚ Celsius ambient temperature, and 100% load factor. ** Data was extracted from Okonite Company Engineering Data for Copper and Aluminum Conductor Electrical Cables.

B. Secondary and Service Cable

Main switch/pull section shall be per Equipment Utility Service Requirements Committee (EUSERC) requirements. Secondary and service cable shall be rated at 600V, aluminum type with XHHW-2 insulation. Secondary cable shall be sized based on expected initial demand plus additional growth in 5 years. Service cable shall be sized to meet the design ampacity including derating factor. Cables shall be furnished and installed by the customer in a conventional conduit system. There are instances in existing installations that APU will allow the use of copper service cables in lieu of aluminum cables such as if the conduit size is not adequate to serve an upgraded service or if it is not feasible to install new conduits due to field conditions.

In certain cases, existing installations use direct buried secondary cable. If a panel needs to be upgraded or replaced, the direct buried secondary cable from the transformer to the panel will have to be replaced with new conduit and cable.

Table 3-5: Secondary/Service Cable Ampacity summarizes the different cable sizes available as APU stock items with the corresponding ampacity.

http://okonite.com/okonite-wire-and-cable-product-brochures/Engineering-Handbook.pdf



REVISION NO. 0

DATE: 03-07-2013

DESIGN MANUAL

DM 3 PAGE 13 OF 21

Table 3-5: Secondary/Service Cable Ampacity

Conductor Size Copper (Amps)

Aluminum (Amps) AWG kcmil

#2 - 146 - 1/0 - 193 150 4/0 - 290 226 - 350 - 304 - 500 471 372 - 750 585 468

* Ampacity values are based on 90˚ Celsius conductor temperature, 20˚ Celsius ambient temperature, and 100% load factor with neutral conductor carrying unbalanced current only. ** Data was extracted from Okonite Company Engineering Data for Copper and Aluminum Conductor Electrical Cables.

3.5 Substructure Selection

Substructures shall be installed to accommodate design ampacity including derating factor.

A. Equipment Structure Location

1. Equipment structures should be located so that vehicle access adjacent to structures will be provided for initial construction and future operation and maintenance needs.

2. Structures for padmount transformers shall be located a minimum distance from building or

other structures in accordance with Section 3.8 Padmount Transformer Locations and applicable Construction Standards.

3. Padmount equipment must be protected from vehicular traffic. Usually designated

landscape areas or parking lot islands provide protected and accessible structure locations.

4. When locating padmount equipment, care must be taken to avoid placing equipment

where it might create a safety hazard by obstructing the vision of vehicular traffic.

B. Transformer Structure Requirements

1. Transformers should be located so as to minimize the length of service runs to all appropriate service points.

2. Transformer structures shall be sized in accordance with this Design Manual and

applicable Construction Standards. Determine the structure size using the maximum size



REVISION NO. 0


DATE: 03-07-2013

DESIGN MANUAL

DM 3 PAGE 14 OF 21

transformer that is expected to serve design ampacity of service. The structure is typically provided and installed by the customer per Electric Rates, Rules, and Regulations.

C. Conduit Requirements

1. A commercial subsystem shall be designed with two four primary inch conduits. One of the

conduits shall be occupied by the primary cable and the other conduit shall be used as a spare. Spare conduits are used for reliability and operation convenience such as minimizing outages in cases of emergency or if the feeder that feeds the development is from an overhead system and within an underground district. The conduits are typically provided and installed by the customer per Electric Rates, Rules, and Regulations.

2. For undeveloped parcels or speculative C/I developments, two four inch primary conduit

will be provided at every other property line.

3. Service conduits will be four inch and will be installed to accommodate the design ampacity including derating factor. Table 3-6: Number of Conduit Runs based on Pull Section Size summarizes the number of conduits required to serve a pull section size.

Table 3-6: Number of Conduit Runs based on Pull Section Size

Pull Section Size Number of Conduits 400 Amp (1) 4” Conduit 600 Amp (2) 4” Conduit 800 Amp (2) 4” Conduit

1,000 Amp (3) 4” Conduit 1,200 Amp (3) 4” Conduit 1,600 Amp (5) 4” Conduit 2,000 Amp (6) 4” Conduit 2,500 Amp (8) 4” Conduit 3,000 Amp (10) 4” Conduit 4,000 Amp (12) 4” Conduit

The number of bends along a typical service conduit route should be kept to a minimum to facilitate pulling of cable and to minimize the need for pulling structures.

1. In general, service conduit runs up to 250 feet in length are acceptable if they contain no

more than a summation of 180 degree bend in total.

2. In general, service conduit runs up to 500 feet in length are acceptable if they contain no more than a summation of 90 degree bend in total.


REVISION NO. 0

DATE: 03-07-2013

DESIGN MANUAL

DM 3 PAGE 15 OF 21

If the number of bends or length of conduit run exceeds this criterion, shortening the length of the service conduits by locating the source closer to the service point is preferred. Installation of a pull box is acceptable if the location does not allow the source to be close to the service.

Section DM7 provides a detailed discussion for cable pulling calculations, and should be utilized for specific designs.

D. Capacitor Structure Requirements

Capacitors are generally installed in circuits in order to improve the power factor. Capacitor placement should be reviewed by System Planning and if it is required, the capacitor structure should be installed at the same time as other utility structures.

Request for System Planning review for future padmount capacitors should be made when there is a development that has large inductive loading such as motors that are greater than 500 horsepower. In underground conversion projects, the capacitive reactance of the new cables being added to the system may reduce or eliminate the need for capacitor placement. Therefore, existing overhead capacitors should not be automatically replaced by padmount capacitors. Such capacitor replacements should be first reviewed by System Planning.

3.6 Feeder Interface

The number of C/I subsystem connections to the feeder should be kept to a minimum. Generally, groups of transformers should be connected as subsystems served from switch positions. Figure 1-1: Relationship between UG Feeder and Subsystems in Section DM 1, Figure 2-1: Padmount Switch Applications – PMC, Figure 2-2: Padmount Switch Applications – PMV and Figure 2-3: Subsurface Switch Applications – VGS in Section DM 2 provide examples.

3.7 Subsystem Design

The following items utilize the design criteria outlined above to select and incorporate transformers, cable, and substructures into recommended subsystem designs.

A. Subsystems are fed from a switch position. T-taps shall not be used because there is no

flexibility for switching.

B. Subsystems will be radial off the feeder. Looped subsystems may be considered when there are multiple transformers for reliability and isolation purposes.

C. Radial or looped subsystems will be designed with 200A load break switches. The typical

application is to use a three-way Submersible Gas Switch (SGS). There are existing junctions in the system and if space is available, then the preferred design is to replace junctions with an SGS switch to provide optimal safety for field crews during switching operations.

REVISION NO. 0


DATE: 03-07-2013

DESIGN MANUAL

DM 3 PAGE 16 OF 21

3.8 Padmount Transformer Locations

Padmount transformers installed at ground level shall conform to the following:

A. Padmount transformers shall not be located directly in front of doors, stairways, or beneath windows which can be opened.

B. Padmount transformers shall be so located that the clearances from buildings or other

structures are maintained in order to ensure adequate space for operating and maintenance, minimize vibration hums, and meet fire safety requirements.

C. Padmount transformers shall not obstruct the vision of vehicular traffic.

D. Clear vehicle access of 12 feet minimum shall be available immediately adjacent to one side of

the transformer at all times in order to provide access for transformer maintenance.

E. Transformer structures will normally be installed only in non-traffic areas. Protection is required when transformer is exposed to traffic. This protection may be in the form of barriers, barricades, or protective posts.

F. When padmount transformers are installed in direct view of the general public, they shall not

detract from the visual appearance of the right of way.

G. The required minimum clearance and Public Utility Easement shall be in conformance with applicable Construction Standards. For a 6’ X 8’ pad, the clearance is 3’ on all 3 sides and 10’ in front. For an 8’ X 10’ pad or 10’ X 12’ pad, the clearance is 5’ on all 3 sides and 10’ in front.

Figure 3-1: Clearance Requirement from Buildings for Padmounted Transformers shows typical transformer clearances from buildings.


REVISION NO. 0

DATE: 03-07-2013

DESIGN MANUAL

DM 3 PAGE 17 OF 21

Figure 3-1: Clearance Requirement from Buildings for Padmounted Transformers

Notes:

1. No portion of building or building structure shall overhang any part of padmounted

transformer.

2. For fireproof door for exits from public assembly such as auditorium, the 10’ clearance to transformer should be increased to 25’.

3.9 Medium Voltage Primary Metering

A. Metering Requirements

1. Anaheim Public Utilities primary metering configuration shall be “Hot Sequence”. It is

defined as the meter being placed ahead of customer’s main power circuit breaker. This configuration establishes a definite dividing line between Anaheim Public Utilities and the customer and will prevent connection of unmetered customer loads to the service equipment.

REVISION NO. 0


DATE: 03-07-2013

DESIGN MANUAL

DM 3 PAGE 18 OF 21

2. The primary metering switchgear shall be isolated from Anaheim Public Utilities electrical system by a padmount disconnect switch (PMH-3).

3. The padmount switch shall be located near the customer's switchgear. The location of the

padmount disconnect switch shall be coordinated with Anaheim Public Utilities Electrical Engineering division.

4. All primary metering equipment shall be installed by Anaheim Public Utilities in the

metering section of the customer installed switchgear. This will include metering current transformers, voltage transformers, voltage transformer primary fuses, meters, and test switches. All voltage transformers shall be protected on the primary side with fused disconnects. The voltage transformer fuses shall be sized to protect the voltage transformer against faults. The metering section shall be in accordance with Section 400 of EUSERC requirements.

5. The incoming 15 kV cable shall be terminated in the pull/termination section of the

switchgear. The pull/termination section of the switchgear shall be in accordance with Section 400 of EUSERC requirements.

B. Customer’s Responsibility

1. Customer's circuit breaker shall coordinate with Anaheim Public Utilities protective devices

at the substation breaker.

2. Customer shall supply and install 15 kV primary metering equipment in accordance with Section 400 of EUSERC requirements.

3. Customer shall install a pad and vault for the padmount disconnect switch, per Anaheim

Public Utilities Standards.

4. Customer shall install two conduits from designated point of service to the pad and vault and, from the pad and vault to the pull/termination section of primary metering switchgear.

C. Utility Responsibility

1. Anaheim Public Utilities shall supply and install 15 kV system riser equipment located at

the designated point of service.

2. Anaheim Public Utilities shall supply and install a PMH-3 padmount disconnect switch.

3. Anaheim Public Utilities shall supply and install 15 kV cable from the designated point of service to the padmount disconnect switch, and from the padmount disconnect switch to pull/termination section. Anaheim Public Utilities shall terminate and connect the cable at the system riser pole, padmounted disconnect switch and in the pull/termination section.


REVISION NO. 0

DATE: 03-07-2013

DESIGN MANUAL

DM 3 PAGE 19 OF 21

4. Anaheim Public Utilities shall supply and install current transformers, voltage transformers, voltage transformer primary fuses, test switches, and meters. Anaheim Public Utilities shall also install other metering or recording devices.

Figure 3-2: Typical Single Line Diagram for Medium Voltage Primary Metering shows a typical single line diagram for medium voltage primary metering accepted by Anaheim Public Utilities.

Figure 3-2: Typical Single Line Diagram for Medium Voltage Primary Metering

REVISION NO. 0


DATE: 03-07-2013

DESIGN MANUAL

DM 3 PAGE 20 OF 21

4.0 SAMPLE CALCULATIONS

4.1 Estimating Demand Using Customer Plans and Connected Load (Method One) The following provides an example of estimating the demand for the new restaurant. Load Schedule: Lighting 20 kW Air Conditioning 60 kW Cooking 100 kW Receptacles 20 kW Spare 10 kW Customer demand (kW) = Sum of connected load times 50% demand factor. Lighting @ 50% = 0.50*20 kW = 10 kW Air Conditioning @ 50% = 0.50*60 kW = 30 kW Cooking @ 50% = 0.50*100 kW = 50 kW Receptacles @ 50% = 0.50*20 kW = 10 kW Total customer demand = 10+30+50+10 = 100 kW From Table 3-1: Demand by Type of Occupancy (Restaurants >3,000 sq.ft.) = 0.87 PF Spare or future load not considered. Customer demand (kVA) = kW / PF = 100 / 0.87 = 114.94 kVA

4.2 Estimating Demand Using Square Footage (Method Two) The following provides an example of estimating the demand and load factor using average demand per square foot by type of occupancy: Given data: 800 Amp Main Switch Board for a restaurant 120/208V, 3 phase, 4 wire 7,000 sq. ft. From Table 3-1: Demand by Type of Occupancy (Restaurants >3,000 sq.ft.) = 14.5 VA/sq. ft.

kVA Demand = (sq. ft. * VA/sq. ft.) / 1,000 kVA Demand = (7,000*14.5) / 1,000 Customer demand (kVA) = 101.50 kVA


REVISION NO. 0

DATE: 03-07-2013

DESIGN MANUAL

DM 3 PAGE 21 OF 21

4.3 Estimating Demand Using Historical Information (Method Three) The following provides an example of estimating the demand for the new restaurant using historical billing information for similar restaurants of comparable size. Using billing history, the following has been determined as the peak kW demand for the previous 12 billing periods. kW = 96.3 kW Customer demand (kVA) = kW / PF = 96.3 / 0.87 = 110.69 kVA Since the difference of either Method “2” or Method “3” is less than 25 percent compared to Method “1”, all three methods can be used in the calculation. Using the average of the three methods, 114.94+101.50+110.69 / 3, the estimated demand is 109.04 kVA. Therefore, a 150 kVA padmount transformer will be sufficient to feed expected initial demand plus additional growth in 5 years.

Section DM 4

RESIDENTIAL SUBSYSTEMS


REVISION NO. 0

DATE: 03-07-2013

DESIGN MANUAL

DM 4 PAGE 1 OF 5

SECTION DM 4: RESIDENTIAL SUBSYSTEMS


3.1 Demand Estimating 2

3.2 Service Points 2

3.3 Transformer Selection 3

3.4 Cable Selection/Secondary and Service Planning 3

3.5 Feeder Interface 4

3.6 Subsystem Design 4 4.0 SAMPLE CALCULATIONS 5

REVISION NO. 0


DATE: 03-07-2013

DESIGN MANUAL

DM 4 PAGE 2 OF 5

DM 4: RESIDENTIAL SUBSYSTEMS 1.0 SCOPE This section provides the criteria for designing residential underground distribution facilities. This includes demand estimating, service points, transformer selection, cable selection, feeder interface, and subsystem design. 2.0 DESIGN CONCEPT Existing overhead residential subsystems are to be designed with #4 ACSR overhead wire. Overhead residential subsystems are to be designed as radials from the main feeder. The overhead transformers are fused with fused cut-outs. New residential subsystems are normally installed using underground residential subsystems. Use of overhead residential subsystems for new installations are only authorized in situations where underground is not feasible, and may only be authorized by the designer’s supervisor. Underground residential subsystems are to be designed with 1/0 underground cable. Underground residential subsystems are to be designed as fused loop configuration using switched, fused transformers. The switch on one of the transformers will be normally open to break the loop configuration and create two fused radials with balanced load on each side of that switch. Although there are existing junctions in residential subsystems, junctions should be replaced with an SGS switch if space is available. Underground residential subsystems may be served from feeder switch positions or 3 way gas switches. 3.0 DESIGN CRITERIA

3.1 Demand Estimating

The basic load determination methods for residential applications are included in Section 3.3: Transformer Selection and Section 3.4: Cable Selection/Secondary and Service Planning.

Load is addressed in these sections to give consideration to diversity as it applies to various portions of residential subsystem design.

3.2 Service Points

One service point will normally be provided for each single family unattached residence, in accordance with Electric Rates, Rules & Regulations. For new installations, the meter location should be on the side wall of the building to allow for ease of access for meter readers as well as for field and meter shop personnel. For existing installations, a meter spot report will need to be obtained from the utilities inspector to determine the best location for an upgraded service.

Multiple occupancy buildings will have the meters grouped at one location per building. Additional service points may be provided for Utility’s operating convenience.


REVISION NO. 0

DATE: 03-07-2013

DESIGN MANUAL

DM 4 PAGE 3 OF 5

3.3 Transformer Selection

A. If existing facilities are overhead, overhead transformers are the likely option for replacement or upgrade. If existing facilities are underground, padmount and subsurface transformers are acceptable designs.

B. Minimize the number of transformer locations by maximizing the number of residential

customers per transformer while meeting voltage drop calculations and cable pulling tension calculations. It is generally more economical to install 50 or 75 kVA transformers depending on lot sizes and size of homes, rather than 25 kVA transformers.

C. 100 kVA padmount and subsurface transformers are normally used for new multiple custom

home developments, or for upgrades.

D. Use the design criteria in Section DM 5 Transformer Loading to size residential transformers.

E. The demand for custom homes above 3,600 square feet is to be calculated by using a 50% demand factor for total connected load (air conditioning units, lighting, receptacles, cooking, etc.). Transformer size shall be determined by calculation method (See 4.0 Sample Calculations).

An example of estimating demand in custom homes is included in Sample Calculations.

3.4 Cable Selection/Secondary and Service Planning

A. Secondary overhead conductors and underground cables shall be sized based on expected

initial demand plus additional growth in 5 years. Main panel shall be per Equipment Utility Service Requirements Committee (EUSERC) requirements.

1. In existing overhead residential subsystems, 100 Amp and 200 Amp services shall be

designed using #2 aluminum triplex overhead conductors.

Existing customers in overhead residential subsystems have the option to go through the HUG (Home Undergrounding) Program which is a rebate based program designed to help Anaheim homeowners reduce the cost of replacing existing overhead service conductors. A conversion can be done at almost any time. If a customer is doing a remodel, adding a swimming pool or upgrading a service, it is a good time to consider undergrounding the service conductors.

2. In new or existing underground residential subsystems, a 100 Amp panel shall be

designed using #2 aluminum triplex underground cable. A 200 Amp panel shall be designed using 1/0 aluminum triplex underground cable. A 400 Amp, self-contained, single phase meter panel (Class 320 meter) shall be designed using 350 kcmil triplex underground cable.

REVISION NO. 0


DATE: 03-07-2013

DESIGN MANUAL

DM 4 PAGE 4 OF 5

B. For new underground residential subsystems such as tract homes, the preferred design is to design the secondaries with pull boxes and transformers on both sides of the street to minimize crossings on the street. Generally, the number of secondary connections in pull boxes is limited to four connections (one feed in, one feed out, and service to two homes) and should be located between property lines as close as practical to the homes they are to serve while meeting voltage drop calculations, flicker calculations and cable pulling tension calculations.

3.5 Feeder Interface

The residential subsystem connections to the feeder should be designed as to reduce the required number of feeder switches and/or switch positions. Groups of fused radial or looped subsystems forming three phase balanced loads should be connected to the feeder from a switch position.

3.6 Subsystem Design

A. The primary voltage for a residential subsystem should be designed using 6.9 kV voltage

which is a single phase distribution system that consist of one underground cable with a concentric neutral. Each fused radial or loop on each phase should be phase marked on the construction drawings.

B. Maximize the kVA per radial or loop. It should be noted that if there are more than three

transformers, the subsystem should be designed with a looped feed for ease of maintenance and switching. If one transformer in the loop needs to be maintained, it can be switched off to be isolated from the loop and the other transformers within the loop can be back fed from the other direction minimizing the outage within the affected area.

C. Subsystems should be planned and cables routed so as to reduce the total length of cable to

reduce cost while meeting voltage drop calculations and cable pulling tension calculations.

D. Although there are existing residential subsystems with direct buried cable, cables for residential subsystems will be installed in conduit. Primary cables shall be 1/0 or 4/0 cable in a conventional conduit system. As a consideration of high fault duty at the service which is above 10 kAIC, the length of the secondary or service can be extended while meeting voltage drop calculations and cable pulling tension calculations.

E. For switching purpose, the preferred method is to utilize a PMC equipped with a 200 Amp

fused position. An alternative is to use a PMV with a 200 Amp position as the source for radial or loop configuration. If a VGS or an existing GSE switch is to be the source, utilize a single phase padmounted Distribution Fuse Cabinet (DFC) or Molded Vacuum Interrupter (MVI).


REVISION NO. 0

DATE: 03-07-2013

DESIGN MANUAL

DM 4 PAGE 5 OF 5

4.0 SAMPLE CALCULATIONS Custom Home Demand Estimating Using a 50% demand factor for total connected load estimate the kilowatt customer demand for a custom home that is 4,500 square feet with the following load schedule: Air conditioning (two units) (1) three ton, (1) five ton (total 8 kW) Electric range Not given, assume 8 kW Dishwasher Not given, assume 1.2 kW Swimming Pool 2 kW Tennis Court Lighting 4 kW Internal Lighting 4 kW Convenience Outlets 5 kW To obtain the estimated diversified demand, multiply each connected load by the appropriate demand factor by 50%. Air Conditioning @ 50% = 0.50*8 kW =4.00 kW Electric Range @ 50% = 0.50*8 kW =4.00 kW Dish Washer @ 50% = 0.50*1.20 kW =0.60 kW Swimming Pool @ 50% = 0.50*2 kW =1.00 kW Tennis Court Lighting @ 50% = 0.50*4 kW =2.00 kW Internal Lighting @ 50% = 0.50*4 kW =2.00 kW Convenience Outlets @ 50% = 0.50*5 kW =0.25 kW Total customer demand = 4.00+4.00+0.60+1.00+2.00+2.00+0.25 = 13.85 kW Therefore, a 25 kVA transformer will be sufficient to feed expected initial demand plus additional growth in 5 years.

Section DM 5

TRANSFORMER LOADING

TRANSFORMER LOADING

REVISION NO. 0

DATE: 03-07-2013

DESIGN MANUAL

DM 5 PAGE 1 OF 5

SECTION DM 5: TRANSFORMER LOADING

TABLE OF CONTENTS No. TITLE PAGE 1.0 SCOPE 2 2.0 RESIDENTIAL TRANSFORMER LOADING 2 2.1 Residential Transformer Loading Criteria 2 2.2 Transformers Serving Custom Homes 2 3.0 COMMERCIAL/INDUSTRIAL TRANSFORMER LOADING 3 4.0 SAMPLE CALCULATIONS 3 4.1 Residential Development – Single-Family Residential 3 4.2 Residential Development – Multi-Family Residential 4 4.3 Residential Development – Custom Home 4

REVISION NO. 0

TRANSFORMER LOADING

DATE: 03-07-2013

DESIGN MANUAL

DM 5 PAGE 2 OF 5

DM 5: TRANSFORMER LOADING 1.0 SCOPE This Section provides the loading criteria for transformers serving residential and commercial/industrial loads. In general, as a guideline, underground transformers are loaded up to 80% of its capacity and overhead transformers are loaded up to 100% of its capacity. Overhead transformers can be loaded up to 100% of its capacity due to the cooling factor of air. 2.0 RESIDENTIAL TRANSFORMER LOADING

2.1 Residential Transformer Loading Criteria

A. For single or multiple residential units with an area of less than 1,500 square feet, use 3-5 kVA per unit to determine the appropriate transformer size. 5 kVA may be used if the unit uses an electric stove and oven. An electric stove and oven is normally installed in newer multiple residential units.

B. For single or multiple residential units with an area between 1,500 to 2,500 square feet, use 5

kVA per unit to determine the appropriate transformer size. This may be increased to 10 kVA per unit if each unit has a combination of multiple air conditioning units and/or an electric stove and oven.

C. For single residential units with an area between 2,500 to 3,600 square feet, use 10 kVA per

unit to determine the appropriate transformer size.

D. The number of transformer locations should be kept to a minimum by maximizing the number of residential customers per transformer. Generally, it is more economical to install 50 or 75 kVA transformers depending on lot sizes and size of homes. Site specific analysis must be performed to establish the most economical design.

E. In single family developments, 100 and 167 kVA transformers shall not normally be used for

new installations. In multi-family developments, 100 and 167 kVA transformers may be used for new installations.

F. Designers are reminded that using square footage in this Section is only for choosing

transformers for the preliminary design. The design must be finalized by voltage drop and flicker calculations per Section DM 7.

2.2 Transformers Serving Custom Homes

When serving custom homes above 3,600 square feet the total customer demand is determined and then the transformer size is selected from the available sizes.

TRANSFORMER LOADING

REVISION NO. 0

DATE: 03-07-2013

DESIGN MANUAL

DM 5 PAGE 3 OF 5

The demand for custom homes above 3,600 square feet is to be calculated by using a 50% demand factor for total connected load (air conditioning units, lighting, receptacles, cooking, etc.).

An example of estimating demand in custom homes is included in Sample Calculations.

See Section Dm 4: Residential Subsytems for a detailed discussion on this topic. 3.0 COMMERCIAL/INDUSTRIAL TRANSFORMER LOADING Transformer capacity shall be installed to supply the sum of all loads to be served. Generally, no diversity should be expected among individual customers in commercial and industrial areas. The transformer selected shall be the smallest that will handle the expected load in five years within the allowable limits. See Section Dm 3: Commercial/Industrial Subsytems for a detailed discussion on this topic. 4.0 SAMPLE CALCULATIONS

4.1 Residential Development – Single-Family Residential

A new residential development consists of 55 homes. All the homes have air conditioning and the square footage of the models is between 1,500 to 2,500 square feet with an air conditioner in all the models. Each model also has a gas stove and oven.

Given Data:

55 Single-Family Homes 1,500 to 2,500 square feet with an air conditioner

First, we will determine the total kVA of the homes.

kVA per Home Homes Total kVA

5 X 55 = 275 kVA

Minimizing the number of transformers while maximizing the number of homes served per transformer, we can first assume the use of 75 kVA transformers. Each 75 kVA transformer can serve up to 12 homes using the 80% loading criteria for underground transformers. The preliminary design for the project should be for five 75 kVA transformers, provided that the design for secondary and service meets voltage drop and flicker criteria. Specific lot sizes and lot arrangement may require the use of some 50 kVA transformers instead of 75 kVA transformers or use of (7) 50 kVA transformers instead of (5) 75 kVA transformers.

REVISION NO. 0

TRANSFORMER LOADING

DATE: 03-07-2013

DESIGN MANUAL

DM 5 PAGE 4 OF 5

4.2 Residential Development – Multi-Family Residential

A new residential development consists of 160 apartment units in (8) buildings (each building containing 20 units). The average size of the apartments is 1,200 square feet. Each unit has one air conditioning unit. Determine the number and size of transformers.

Given Data:

160 units (8) buildings (with 20 units in each building) 1,200 square feet per unit One air conditioning per unit

First, we will determine the total kVA of each building.

kVA per unit Units Total kVA

3 X 20 = 60 kVA

Approximately eight 75 kVA transformers are needed in the preliminary design using the 80% loading criteria for underground transformers.

4.3 Residential Development – Custom Home

Using a 50% demand factor for total connected load estimate the kilowatt customer demand for a custom home that is 4,500 square feet with the following load schedule: Air conditioning (two units) (1) three ton, (1) five ton (total 8 kW) Electric range Not given, assume 8 kW Dishwasher Not given, assume 1.2 kW Swimming Pool 2 kW Tennis Court Lighting 4 kW Internal Lighting 4 kW Convenience Outlets 5 kW To obtain the estimated diversified demand, multiply each connected load by the appropriate demand factor by 50%. Air Conditioning @ 50% = 0.50*8 kW =4.00 kW Electric Range @ 50% = 0.50*8 kW =4.00 kW Dish Washer @ 50% = 0.50*1.20 kW =0.60 kW Swimming Pool @ 50% = 0.50*2 kW =1.00 kW Tennis Court Lighting @ 50% = 0.50*4 kW =2.00 kW Internal Lighting @ 50% = 0.50*4 kW =2.00 kW Convenience Outlets @ 50% = 0.50*5 kW =0.25 kW

TRANSFORMER LOADING

REVISION NO. 0

DATE: 03-07-2013

DESIGN MANUAL

DM 5 PAGE 5 OF 5

Total customer demand = 4.00+4.00+0.60+1.00+2.00+2.00+0.25 = 13.85 kW Therefore, a 25 kVA transformer will be sufficient to feed expected initial demand plus additional growth in 5 years.

Section DM 6

VOLTAGE DROP, FLICKER, AND SHORT CIRCUIT DUTY


REVISION NO. 0

DATE: 03-07-2013

DESIGN MANUAL

DM 6 PAGE 1 OF 10

SECTION DM 6: VOLTAGE DROP, FLICKER, AND SHORT CIRCUIT DUTY

TABLE OF CONTENTS No. TITLE PAGE 1.0 SCOPE 3 2.0 DESIGN CRITERIA 3 2.1 Voltage Drop – Residential and Commercial 3 2.2 Flicker – Residential 3

2.3 Flicker – Commercial/Industrial 5 3.0 VOLTAGE DROP AND CALCULATIONS 6 3.1 Single Phase Voltage Drop 6 3.2 Three Phase Voltage Drop 6 4.0 SHORT CIRCUIT DUTY 7 4.1 Single-Phase Customers 7 4.2 Three-Phase Customers 7 5.0 SAMPLE CALCULATIONS 9

REVISION NO. 0


DATE: 03-07-2013

DESIGN MANUAL

DM 6 PAGE 2 OF 10

TABLES No. TITLE PAGE 6-1 Percent Flicker through Overhead Transformer 4 6-2 Percent Flicker through Underground Transformer 4 6-3 Percent Flicker through Overhead Secondary and Service Conductors 4 6-4 Percent Flicker through Underground Secondary and Service Cables 5 6-5 Cable Resistance per Thousand Foot 6 6-6 Short Circuit Duty for Single-Phase 120/240 Volt Customers 7 6-7 Short Circuit Duty for Three-Phase 208/120 Volt Customers 8 6-8 Short Circuit Duty for Three-Phase 480/277 Volt Customers 8


REVISION NO. 0

DATE: 03-07-2013

DESIGN MANUAL

DM 6 PAGE 3 OF 10

DM 6: VOLTAGE DROP, FLICKER, AND SHORT CIRCUIT DUTY 1.0 SCOPE This Section provides the criteria and methods for evaluation of voltage drop and flicker for overhead and underground systems. It also provides information about Anaheim Public Utilities’ fault current contribution (short circuit duty) at the utility transformers. 2.0 DESIGN CRITERIA The secondary and service cables and conductors used in the design should be sufficient to meet both the expected demand and the voltage drop and flicker criteria as described in this Section.

2.1 Voltage Drop – Residential and Commercial

Voltage drop describes the difference of the supplied voltage source at the transformer secondary to the customer’s meter. Voltage drop is caused by the impedance of the secondary and service conductors. Although the American National Standard C84.1 allows a voltage drop of five percent (5%), it is preferred to design services where the total voltage drop should not exceed three percent (3%).

The formula used for Voltage Drop can be found in Section 3.0. Sample calculations are provided in Section 5.0.

2.2 Flicker – Residential

Flicker is a visible change in brightness of a lamp due to rapid fluctuations in the voltage dip of the power supply. The source of this is the voltage drop generated over the source impedance of the grid by the changing load current of an equipment or facility. These fluctuations in time generate flicker. Flicker may also affect sensitive electronic equipment such as television receivers or industrial processes relying on constant electrical power.

Total residential flicker should not exceed five percent (5%) of the source voltage on overhead and underground installations when we consider this as an addition to the already allowable voltage drop.

The formula used to determine flicker is complex and time consuming to calculate. Table 6-1 through Table 6-4 are tables obtained from Southern California Edison Standards which have performed the calculations to determine flicker through transformer and conductors/cables.

Table 6-1: Percent Flicker through Overhead Transformer and Table 6-2: Percent Flicker through Underground Transformer provides the percent flicker through the conductor/cable as a function of air conditioner (A/C) size and conductor/cable size and length.

REVISION NO. 0


DATE: 03-07-2013

DESIGN MANUAL

DM 6 PAGE 4 OF 10

Table 6-1: Percent Flicker through Overhead Transformer

Transformer Size

A/C Tons 2 3 4 5

25 1.4 2.1 2.8 3.2 50 0.7 1.0 1.4 1.6 75 0.5 0.7 0.9 1.1

* Table condensed from Southern California Edison Standards.

Table 6-2: Percent Flicker through Underground Transformer

Transformer Size

A/C Tons 2 3 4 5

25 1.4 2.1 2.8 3.2 50 0.7 1.0 1.4 1.6 75 0.5 0.7 0.9 1.1


Table 6-3: Percent Flicker through Overhead Secondary and Service Conductors and Table 6-4: Percent Flicker through Underground Secondary and Service Cables provides the percent flicker through the conductor/cable as a function of air conditioner (A/C) size and transformer size.

Table 6-3: Percent Flicker through Overhead Secondary and Service Conductors

Distance

(feet) 2 Ton 3 Ton 4 Ton 5 Ton

#2 1/0 4/0 #2 1/0 4/0 #2 1/0 4/0 #2 1/0 4/0 20 0.3 0.2 0.1 0.4 0.3 0.2 0.5 0.4 0.2 0.6 0.4 0.2 40 0.5 0.3 0.2 0.8 0.5 0.3 1.1 0.7 0.4 1.2 0.8 0.4 60 0.8 0.5 0.3 1.2 0.8 0.4 1.6 1.1 0.6 1.8 1.2 0.7 80 1.0 0.7 0.4 1.6 1.0 0.6 2.1 1.4 0.8 2.4 1.6 0.9

100 1.3 0.9 0.5 2.0 1.3 0.7 2.7 1.8 1.0 3.0 2.0 1.1 120 1.5 1.0 0.6 2.4 1.6 0.9 3.2 2.1 1.2 3.6 2.4 1.3 140 1.8 1.2 0.7 2.7 1.8 1.0 3.7 2.5 1.4 4.2 2.8 1.5 160 2.1 1.4 0.8 3.1 2.1 1.2 4.3 2.8 1.6 4.8 3.2 1.8 180 2.3 1.5 0.9 3.5 2.3 1.3 4.8 3.2 1.8 5.4 3.6 2.0 200 2.6 1.7 0.9 3.9 2.6 1.4 5.4 3.5 2.0 6.0 4.0 2.2



REVISION NO. 0

DATE: 03-07-2013

DESIGN MANUAL

DM 6 PAGE 5 OF 10

Table 6-4: Percent Flicker through Underground Secondary and Service Cables

Distance (feet)

2 Ton 3 Ton 4 Ton 5 Ton 1/0 4/0 350 1/0 4/0 350 1/0 4/0 350 1/0 4/0 350

20 0.2 0.1 0.1 0.3 0.1 0.1 0.4 0.2 0.1 0.4 0.2 0.2 40 0.3 0.2 0.1 0.5 0.3 0.2 0.7 0.4 0.3 0.8 0.4 0.3 60 0.5 0.3 0.2 0.8 0.4 0.3 1.1 0.6 0.4 1.2 0.7 0.5 80 0.7 0.4 0.3 1.0 0.6 0.4 1.4 0.8 0.5 1.6 0.9 0.6

100 0.9 0.5 0.3 1.3 0.7 0.5 1.8 1.0 0.7 2.0 1.1 0.8 120 1.0 0.6 0.4 1.6 0.9 0.6 2.1 1.2 0.8 2.4 1.3 0.9 140 1.2 0.7 0.5 1.8 1.0 0.7 2.5 1.4 0.9 2.8 1.5 1.1 160 1.4 0.8 0.5 2.1 1.2 0.8 2.8 1.6 1.1 3.2 1.8 1.2 180 1.5 0.9 0.6 2.3 1.3 0.9 3.2 1.8 1.2 3.6 2.0 1.4 200 1.7 0.9 0.7 2.6 1.4 1.0 3.5 2.0 1.4 4.0 2.2 1.5


2.3 Flicker – Commercial/Industrial

Unlike Residential Subsystems, Commercial/Industrial Subsystems normally have individual transformer per customer and the transformer is located close to the service equipment. The flicker through the conductor/cable can be omitted because voltage drop has been reduced. In addition, Commercial/Industrial customers also have ways of reducing flicker such as capacitors, solid state motor starters (soft starters) and voltage regulators for large motors. APU can compensate for flicker in Commercial/Industrial Subsystems by increasing the size of the transformers to handle starting in rush current of large motor loads.

Since the formula used to determine flicker is complex and time consuming to calculate, an extensive flicker study can be done by System Planning for large motor loads if necessary.

Total commercial/industrial flicker should not exceed five percent (5%) of the source voltage on overhead and underground installations when we consider this as an addition to the already allowable voltage drop.

REVISION NO. 0


DATE: 03-07-2013

DESIGN MANUAL

DM 6 PAGE 6 OF 10

3.0 VOLTAGE DROP CALCULATIONS The voltage drop can be calculated from the following formula; although an approximation, this method is sufficiently accurate for T&D engineering calculations. Use the resistance of any given cable from Table 6-5: Cable Resistance per Thousand Foot.

3.1 Single Phase Voltage Drop VD = (2*L*R*I) / 1,000 %VD = (VD / VS)*100 Where: VD = Voltage Drop %VD = Percentage of Voltage Drop VS = Source Voltage L = One way length of circuit feeder R = Resistance factor per NEC Chapter 9, Table 8, in ohm/kft I = Load current in Amperes

3.2 Three Phase Voltage Drop VD = (2*L*R*I*(√3 / 2)) / 1,000 or (√3*L*R*I) / 1,000 %VD = (VD / VS)*100 Where: VD = Voltage Drop %VD = Percentage of Voltage Drop VS = Source Voltage L = One way length of circuit feeder R = Resistance factor per NEC Chapter 9, Table 8, in ohm/kft I = Load current in Amperes

Table 6-5: Cable Resistance per Thousand Foot

Cable Size Ohms/1,000 feet #2 0.3190 1/0 0.2010 4/0 0.1000 350 0.0605 750 0.0282

1,000 0.0212

* Table 6-5: Cable Resistance per Thousand Foot extracted from NEC Chapter 9, Table 8.


REVISION NO. 0

DATE: 03-07-2013

DESIGN MANUAL

DM 6 PAGE 7 OF 10

In order to determine the demand for voltage drop calculations, use the information in Section DM 4, Residential Subsystems, for residential demand estimating, and Section DM 3, Commercial/Industrial Subsystems, for commercial/industrial demand estimating. Once the demand is known in kW, calculate the current I using the formulas in Section DM 10, Formulas. 4.0 SHORT CIRCUIT DUTY The following information is for responding to customer inquiries about available fault current at the secondary terminals of the transformer. The customers installed service entrance equipment and protection devices (fuses and/or circuit breakers) must be capable of interrupting and withstand the available fault current. Service entrance equipment shall be sized for the short circuit current available at its service terminations. Tables 6-2 through 6-4 shows the available fault current at the secondary terminals of the transformer. In order to use these tables correctly, first determine the size and type of the transformer that will supply power to the service equipment in question. Then from the tables, read the fault current amperes across the kVA size of that transformer in the correct column corresponding to the transformer type. These values will be given to the customer/consultant of the project for them to properly calculate the available fault current at the service entrance equipment based on the service conductor/cable length and size.

4.1 Single-Phase Customers Table 6-6: Short Circuit Duty for Single-Phase 120/240 Volt Customers shows the available fault current at the secondary terminals of a single phase transformer.

Table 6-6: Short Circuit Duty for Single-Phase 120/240 Volt Customers

Transformer

Size 1Ø Fault Current Amperes for Voltage Listed, 120/240V, 1Ø

Pole Type Padmount Type BURD Type Impedance At Secondary Impedance At Secondary Impedance At Secondary

25 < 2.5% 11,000 > 1.9% 6,000 < 2.5% 11,000 50 < 2.5% 21,000 > 1.9% 11,000 < 2.5% 21,000 75 < 2.5% 32,000 > 1.9% 17,000 < 2.5% 32,000

100 < 2.5% 42,000 > 1.9% 22,000 < 2.5% 42,000 * Transformer impedance extracted from APU transformer specifications. ** Fault current calculated using the formula: I = kVA / (Voltage*Transformer Impedance)

4.2 Three-Phase Customers

Table 6-7: Short Circuit Duty for Three-Phase 208/120 Volt Customers and Table 6-8: Short Circuit Duty for Three-Phase 480/277 Volt Customers show the available fault current at the secondary terminals of a three phase transformer.

REVISION NO. 0


DATE: 03-07-2013

DESIGN MANUAL

DM 6 PAGE 8 OF 10

Table 6-7: Short Circuit Duty for Three-Phase 208/120 Volt Customers

Transformer Size

3Ø Fault Current Amperes for Voltage Listed, 120/208V, 3Ø Pole Type Padmount Type

Impedance At Secondary Impedance At Secondary 75 < 2.5% 21,000 > 3% 7,000

150 < 2.5% 42,000 > 3% 14,000 225 < 2.5% 63,000 - - 300 - - > 3% 28,000 500 - - > 5.75% 25,000 750 - - > 5.75% 37,000

1,000 - - > 5.75% 49,000

* Transformer impedance extracted from APU transformer specifications. ** Fault current calculated using the formula: I = kVA / (√3*Voltage*Transformer Impedance)

Table 6-8: Short Circuit Duty for Three-Phase 480/277 Volt Customers

Transformer Size

3Ø Fault Current Amperes for Voltage Listed, 277/480V, 3Ø Pole Type Padmount Type

Impedance At Secondary Impedance At Secondary 75 < 2.5% 10,000 > 3% 4,000

150 < 2.5% 19,000 > 3% 7,000 225 < 2.5% 28,000 - - 300 - - > 3% 13,000 500 - - > 5.75% 11,000 750 - - > 5.75% 16,000

1,000 - - > 5.75% 21,000 1,500 - - > 5.75% 32,000 2,500 - - > 5.75% 53,000

* Transformer impedance extracted from APU transformer specifications.

** Fault current calculated using the formula: I = kVA / (√3*Voltage*Transformer Impedance)


REVISION NO. 0

DATE: 03-07-2013

DESIGN MANUAL

DM 6 PAGE 9 OF 10

5.0 SAMPLE CALCULATIONS Using the scenario in DM 4 - Residential Subsytems, calculate the Voltage Drop and Flicker if the service equipment is located 100 feet away from the transformer and the panel size is a 400 Amp, self-contained, single phase meter panel (Class 320 meter). Using a 50% demand factor for total connected load estimate the kilowatt customer demand for a custom home that is 4,500 square feet with the following load schedule: Air conditioning (two units) (1) three ton, (1) five ton (total 8 kW) Electric range Not given, assume 8 kW Dishwasher Not given, assume 1.2 kW Swimming Pool 2 kW Tennis Court Lighting 4 kW Internal Lighting 4 kW Convenience Outlets 5 kW To obtain the estimated diversified demand, multiply each connected load by the appropriate demand factor by 50%. Air Conditioning @ 50% = 0.50*8 kW =4.00 kW Electric Range @ 50% = 0.50*8 kW =4.00 kW Dish Washer @ 50% = 0.50*1.20 kW =0.60 kW Swimming Pool @ 50% = 0.50*2 kW =1.00 kW Tennis Court Lighting @ 50% = 0.50*4 kW =2.00 kW Internal Lighting @ 50% = 0.50*4 kW =2.00 kW Convenience Outlets @ 50% = 0.50*5 kW =0.25 kW Total customer demand = 4.00+4.00+0.60+1.00+2.00+2.00+0.25 = 13.85 kW or 57.71 Amps A 25 kVA transformer will be sufficient to feed expected initial demand plus additional growth in 5 years. Since the panel is a 400 Amp, self-contained, single phase meter panel (Class 320 meter), it shall be designed using 350 kcmil triplex underground cable. Using the formula for voltage drop: VD = (2*L*R*I) / 1,000 VD = (2*100*0.0605*57.71) / 1000 VD = 0.6983 Volts %VD = (VD / VS)*100 %VD = (0.6983 / 240)*100 %VD = 0.29%

REVISION NO. 0


DATE: 03-07-2013

DESIGN MANUAL

DM 6 PAGE 10 OF 10

Using Table 6-2: Percent Flicker through Underground Transformer and Table 6-4: Percent Flicker through Underground Secondary and Service Cables, the flicker can be determined with the given data. Percent flicker through the underground transformer will be 3.2% and percent flicker through the underground service cable will be 0.8% with a total of 4.0%. Therefore, the 25 kVA transformer and service cable is adequately sized to feed the new custom home whose service equipment is 100 feet away.

Section DM 7

CABLE PULLING TENSION CALCULATIONS AND

TERMINATIONS

CABLE PULLING TENSION CALCULATIONS AND TERMINATIONS

REVISION NO. 0

DATE: 03-07-2013

DESIGN MANUAL

DM 7 PAGE 1 OF 8

SECTION DM 7: CABLE PULLING TENSION CALCULATIONS AND TERMINATIONS

TABLE OF CONTENTS No. TITLE PAGE 1.0 SCOPE 3 2.0 DESIGN CRITERIA 3 3.0 MAXIMUM ALLOWABLE PULLING TENSIONS 3 4.0 SAMPLE CALCULATIONS 5 4.1 Secondary Cable 5 4.2 Primary Cable 6 5.0 TERMINATIONS 7 5.1 200 Amp 7

5.2 600 Amp 8

REVISION NO. 0


DATE: 03-07-2013

DESIGN MANUAL

DM 7 PAGE 2 OF 8

TABLES No. TITLE PAGE 7-1 Maximum Allowable Pulling Tensions and Cable Weights 4 7-2 Specific Angles of Bend and Coefficients of Friction 5


REVISION NO. 0

DATE: 03-07-2013

DESIGN MANUAL

DM 7 PAGE 3 OF 8

DM 7: CABLE PULLING TENSION CALCULATIONS AND TERMINATIONS 1.0 SCOPE This Section outlines the criteria and parameters for determination of cable pulling stresses on the cable to be pulled in conduits. Designer should calculate the maximum pulling tensions and identify the means of cable pulling (pulling eye or pulling grip), and the direction of the pull. The maximum allowable tensions shall not be exceeded. 2.0 DESIGN CRITERIA In designing cable runs, proper use of bends and sweeps must be observed. In general, the difference between bends and sweeps is their radii. Minimum radius for al bends is 36 inches and the maximum radius for all bends is 60 inches. The radius of each bend is determined by conduit size, as shown below:

1. 36 inches for conduit 3 inches in diameter and smaller 2. 48 inches for conduit 4 inches in diameter 3. 60 inches for conduit 6 inches in diameter

The minimum radius for all sweeps of all size conduits is 12’-6”. Sweeps shall be used for all three phase primary horizontal turns. Bends are used at the bases of primary risers and for secondary or service horizontal and vertical turns. For single-phase residential cable runs bends may be used for primary horizontal turns. Sweeps should be used when installing 600 V XLPE cables larger than 500 kcmil. 3.0 MAXIMUM ALLOWABLE PULLING TENSIONS The following discussion about cable pulling tensions is extracted from the Okonite Company Engineering Data for Copper and Aluminum Conductor Electrical Cables. It applies to all cables that APU uses in T&D. The force required pulling cable into a conduit or the maximum pulling length can be determined from the following:

A. The maximum stresses must not be exceeded when pulling a cable:

1. The maximum tension shall not exceed 0.008 times CM (Circular Mil) area when pulled with a pulling eye attached to the copper or aluminum conductors.

Tm = 0.008*N*CM Where: Tm = maximum tension in pounds N = number of cable in run CM = circular mil area of each conductor

Using the formula above, Table 7-1: Maximum Allowable Pulling Tensions and Cable Weights summarizes the different cable sizes APU stocks with the maximum tensions allowed and their corresponding weights.



REVISION NO. 0


DATE: 03-07-2013

DESIGN MANUAL

DM 7 PAGE 4 OF 8

Table 7-1: Maximum Allowable Pulling Tensions and Cable Weights

AWG kcmil Conductor Weight (pounds/foot)

Number of Conductors 1 2 3 4

#2 - 0.0622 531 1,062 1,593 2,124 1/0 - 0.0991 845 1,690 2,534 3,379 4/0 - 0.1982 1,693 3,386 5,078 6,771 - 350 0.3283 2,800 5,600 8,400 10,000** - 500 0.5160 4,000 8,000 10,000** 10,000** - 750 0.7032 6,000 10,000** 10,000** 10,000** - 1,000 0.9638 6,000* 10,000** 10,000** 10,000**

* The maximum tension for one conductor cable should not exceed 6,000 pounds. ** The maximum tension for two or more conductors should not exceed 10,000 pounds.

2. The maximum tension shall not exceed 1,000 lbs. for non-leaded cables when pulled with a pulling grip. If it exceeds 1,000 pounds, a pulling eye must be used.

3. The maximum tension at a bend shall not exceed 500 pounds times the radius of curvature

of the conduit expressed in feet. Maximum tensions calculated from items 1 or 2 above also cannot be exceeded. Thus, the minimum radius in feet should not be less than R = T/500, where T is the maximum tension per item 1 or 2 above in pounds. However, R must be no less than the minimum bending radius of the cable.

B. The pulling tension in a given horizontal conduit section may be calculated from the following:

1. For a straight section, the pulling tension is equal to the length of the conduit run multiplied

by the weight per foot of the cable and the coefficient of friction, thus:

T = L*W*F Where: T = total pulling tension L = length of conduit run in feet W = weight of cable in pounds per foot f = coefficient of friction

2. For conduits having curved sections, the following formula applies:

Tout = Tin efa Where: Tout = tension out of the curved section Tin = tension into the curved section e = 2.718 (naperian logarithm base) f = coefficient of friction a = angle of the curved section in radians


REVISION NO. 0

DATE: 03-07-2013

DESIGN MANUAL

DM 7 PAGE 5 OF 8

To aid in solving the above formula, values of efa for specific angles of curved sections and coefficients of friction are listed in Table 7-2: Specific Angles of Bend and Coefficients of Friction. For the coefficient of friction, use 0.50 for lubricated conduits and 0.75 for dry conduits.

Table 7-2: Specific Angles of Bend and Coefficients of Friction

Angle of Bend

Angle in Radians

Values of efa 0.75 0.50

15˚ 0.2618 1.22 1.14 30˚ 0.5236 1.48 1.30 45˚ 0.7854 1.80 1.48 60˚ 1.0472 2.19 1.68 90˚ 1.5708 3.25 2.20


4.1 Example 1: Secondary Cable Given Data: 4 X 750 kcmil Aluminum in (1) 4” conduit in dry conduit Radius = 48” or 4’ (secondary conduits) Weight = 0.7032 pounds per foot (from Table 8-1)

efa = 3.25 (from Table 8-2)

Using the formula: Tm = 0.008*N*CM Tm = 0.008*4*750,000 Tm = 24,000 pounds Therefore, the 10,000 pounds limitation (per item A.1) applies.

Permissible maximum tension due to sidewall pressure limitation at curve BC (per item A.3) is 500*4 = 2,000 pounds.

REVISION NO. 0


DATE: 03-07-2013

DESIGN MANUAL

DM 7 PAGE 6 OF 8

TB = TAB = 100*0.7032*0.75 TB = TAB = 52.74 pounds TC = TB* efa efa = 2.718(0.75*1.5708) (a=90˚ in radians from Table 8-2) efa = 3.25 (this confirms the value shown on Table 8-2) TC = 52.74*3.25 TC = 171.41 pounds TCD = 100*0.7032*0.75 TCD = 52.74 pounds

TD = TC + TCD TD = 171.41 + 52.74 TD = 224.15 pounds

Conclusion: The cable can be safely pulled with a pulling grip without exceeding the 10,000 pounds limitation of item A.1 and the permissible maximum tension due to sidewall pressure limitation of item A.3 at curve BC.

4.2 Example 2: Primary Cable

Given Data: 3 X 1,000 kcmil Aluminum in (1) 6” conduit in dry conduit Radius = 12’-6” (primary conduits) Weight = 0.9638 pounds per foot (from Table 8-1)

efa = 3.25 (from Table 8-2)

Using the formula: Tm = 0.008*N*CM Tm = 0.008*3*1,000,000 Tm = 24,000 pounds Therefore, the 10,000 pounds limitation (per item A.1) applies.

Permissible maximum tension due to sidewall pressure limitation at curve BC (per item A.3) is 500*12.5 = 6,250 pounds.


REVISION NO. 0

DATE: 03-07-2013

DESIGN MANUAL

DM 7 PAGE 7 OF 8

TB = TAB = 200*0.9638*0.75 TB = TAB = 144.57 pounds TC = TB* efa efa = 2.718(0.75*1.5708) (a=90˚ in radians from Table 8-2) efa = 3.25 (this confirms the value shown on Table 8-2) TC = 144.57*3.25 TC = 469.85 pounds TCD = 300*0.9638*0.75 TCD = 216.86 pounds

TD = TC + TCD TD = 469.85 + 216.86 TD = 686.71 pounds

Conclusion: The cable can be safely pulled with a pulling grip without exceeding the 10,000 pounds limitation of item A.1 and the permissible maximum tension due to sidewall pressure limitation of item A.3 at curve BC.

5.0 TERMINATIONS In general, termination of cables is done in underground structures that are laid out in a manner to maximize the length of cable segments being terminated and minimize the number of terminations. Cost, operating flexibility, and space requirements must be considered in termination of cables in designing cable systems. In designing the underground cable systems, the designer should calculate the pulling tension and sidewall pressure in both directions for maximum substructure spacing of 1,000 feet. If the limitations do not allow the pull at the maximum length in a segment, then the location of a termination in the design should be revised for a shorter cable run that can be pulled without exceeding the limits. Extra cable length should be included in the design to allow training, looping, and racking the cables in terminating substructures per Construction Standards. This extra length depends on the splicing substructure; in general an additional length equal to the width plus twice the length of the inside walls (W+2L) is considered adequate. Based on cost, the preferred method of terminations is the permanent terminations. This method has limited usage and as a result, straight splices and component “T” splice will be the most prevalent method of terminations. Switches have the highest cost; however their operating flexibility offers advantages over other methods in certain applications. The methods and their specific applications are described in the following sections.

5.1 200 Amp

A. Permanent straight splices are the lowest cost termination method; however they offer no operational capability. These should only be used when the subsystem is located over 1,000 feet away from the load interface or in a splice vault where the underground cable does not meet pulling calculations.

REVISION NO. 0


DATE: 03-07-2013

DESIGN MANUAL

DM 7 PAGE 8 OF 8

B. Junctions is an alternative design that offer a little more operational flexibility compared to permanent straight splices. However, they do have field operating advantages such as single hot stick operation. Recommended applications where this alternative should be used are where frequent operation will be required (more than once per year over the expected 30 year life) or where surface operable space prevents installation of Submersible Gas Switch.

C. Submersible Gas Switches are the most expensive but offer the most operational capability.

They are surface operable in locations such as parkways, parking lots, sidewalks, and landscaped areas. Submersible Gas Switches should be used if there is frequent operation required and if two or more transformers will be served from the load interface.

5.2 600 Amp

A. Permanent straight splices are the lowest cost termination method; however they offer no

operational capability. These should only be used if the designer is certain that no switches will be connected to the splice in future projects or in a splice vault where the underground cable does not meet pulling calculations.

B. Component “T” splices is an alternative design that offer a little more operational flexibility

compared to permanent straight splices. These can be used if the designer is certain that future switches will be connected to the splice in future projects. Only (2) way component “T” splices are allowed for new installations. If (3) or (4) way terminations is required, a Vista Gas Switch must be installed in place of a (3) or (4) way terminations.

C. Viaultmount Gas Switches are more expensive to the previous two splicing methods but offer

the most operational flexibility. Vaultmount Gas Switches must be used in place of a (3) or (4) way termiantions.

Section DM 8

OVERHEAD SYSTEMS

OVERHEAD SYSTEMS

REVISION NO. 0

DATE: 03-07-2013

DESIGN MANUAL

DM 8 PAGE 1 OF 11

SECTION DM 8: OVERHEAD SYSTEMS

TABLE OF CONTENTS No. TITLE PAGE 1.0 SCOPE 3 2.0 DESIGN CONCEPT 3 2.1 12kV Primary Distribution System 3 2.2 Pole Design 3 2.3 Routing and Location of Overhead Lines 3 2.4 Attachments to Anaheim Public Utilities Poles or Structures 4 2.5 Foreign Poles or Structures 4 2.6 Tree Trimming and Clearing of Rights of Way 4 3.0 DESIGN CRITERIA 4 3.1 Conductors 4 3.2 Poles 6 3.3 Crossarms 7 3.4 Guying 7 3.5 Overhead Transformers 8 4.0 SAMPLE CALCULATIONS 8

4.1 Example 1: Pole Class 8

4.2 Example 2: Pole Spans 9

4.3 Example 3: Safety Factor 10

REVISION NO. 0

OVERHEAD SYSTEMS

DATE: 03-07-2013

DESIGN MANUAL

DM 8 PAGE 2 OF 11

TABLES No. TITLE PAGE 8-1 Conductor Properties with Ampacity 5 8-2 Conductor Sizes with Dead End Tensions 5 8-3 Pole Size and Unguyed Usable Strength 6 8-4 Safety Factors for New and In Service Construction per G.O. 95 7

OVERHEAD SYSTEMS

REVISION NO. 0

DATE: 03-07-2013

DESIGN MANUAL

DM 8 PAGE 3 OF 11

DM 8: OVERHEAD SYSTEMS 1.0 SCOPE This section establishes design criteria to be used in designing overhead systems. Specific criteria are given to provide for the design of an overhead pole line, reconductoring and performing wind loading calculations. 2.0 DESIGN CONCEPT Overhead systems are designed with Aluminum Conductors Steel Reinforced (ACSR) conductors, and the more typical application of overhead conductors in Anaheim is for reconductoring projects. Use of overhead construction for new projects are only authorized in situations where underground is not feasible, and may only be authorized by the designer’s supervisor.

2.1 12kV Primary Distribution System

Anaheim Public Utilities 12 kV Primary Distribution System supply existing and new residential and commercial areas. In many cases, existing 12 kV three wire circuits will be converted to four wire (12 kV/6.9 kV) circuits by the addition of the neutral conductor. Construction of four wire circuits should be considered for future planning and/or rebuilds.

The present economic advantage of the four wire systems lies primarily in their use in the Underground Distribution System where single bushing 6.9 kV transformers and associated apparatus can be used. It is not intended that phase to ground connected overhead transformers be used on these four wire overhead systems. Loads may be supplied from any point on that circuit.

2.2 Pole Design

An overhead structure, whether being installed new or on an existing overhead line as part of a rebuild, needs to be reviewed to ensure that the proper structural design and construction methods are used. When the proper design and construction methods are employed, the economic and operational needs of Anaheim Public Utilities will be satisfied.

The overhead system is designed primarily using wood poles to support conductors and equipment. Anaheim Public Utilities Primary Distribution System shall be designed to Grade A and B construction only. All joint pole attachments shall be designed to Grade A construction.

2.3 Routing and Location of Overhead Lines

When planning the construction of any overhead lines, the following shall be carefully considered:

A. Will the City allow overhead construction?

B. Could this line become a future Rule 20 conversion?

REVISION NO. 0

OVERHEAD SYSTEMS

DATE: 03-07-2013

DESIGN MANUAL

DM 8 PAGE 4 OF 11

C. When developing the routing of the line, are there restrictions such as an Underground District been considered?

The route should be selected, so that the total cost of the completed line will be a minimum, while at the same time, giving due consideration to accessibility for maintenance, and the effect of local climate conditions on insulators and other parts of the structures.

Tree hazards should be avoided unless permission can be obtained to cut or trim, and keep trimmed, all trees that will be an obstruction to the line. The probable future extension of the circuits and additional circuits on poles should be kept in mind when selecting the route. Temporary routes should be avoided.

2.4 Attachments to Anaheim Public Utilities Poles or Structures

New or additional attachments to Anaheim Public Utilities poles or structures by a foreign utility, (such as, an owner/member of Southern California Joint Pole Committee); or any other third party, shall not be made except when permission is granted by an authorized Anaheim Public Utilities representative, as outlined in the SCJPC Routine Handbook. In all cases involving a tenant, a wind load calculation must be submitted by either the foreign utility or third party representative for the requested attachment(s). The following information must also be provided: type, diameter, span, quantity of cable, and/or nature of attachment.

2.5 Foreign Poles or Structures

Anaheim Public Utilities attachments to poles or structures owned by a foreign utility (owner/member of SCJPC), shall not be made except when permission is granted as outlined in the SCJPC Routine Handbook. If the company owning the pole is not a party to the SCJPC, Anaheim Public Utilities shall install its own poles if applicable

2.6 Tree Trimming and Clearing of Rights of Way

It is essential for the safe and uninterrupted operation of high voltage lines that they be free from possible short circuiting or grounding in trees. It is, therefore, important that designers consider the possibilities of tree branches interfering, or likely to interfere, with the lines should be cleared.

3.0 DESIGN CRITERIA

3.1 Conductors

Primary conductor sizes are determined by the economic loading limits, and feeder conductor sizes are reviewed by System Planning. Secondary conductors are sized based on customer demand, voltage drop, flicker, and motor starting load. The number, size, height requirements, wind loading, and dead ending tension of conductors, supported by an overhead pole, are the primary factors used in determining the pole strength requirements. Typical overhead construction will utilize crossarm construction for primary voltages and secondary rack (open wire construction) or secondary spool (triplex construction) for secondary voltages.

OVERHEAD SYSTEMS

REVISION NO. 0

DATE: 03-07-2013

DESIGN MANUAL

DM 8 PAGE 5 OF 11

Table 8-1: Conductor Properties with Ampacity list each conductor type and size with properties and continuous ampacity rating that Anaheim Public Utilities uses. This data was obtained from construction standard CO 200.

Table 8-1: Conductor Properties with Ampacity

Conductor Type

Wire Size (AWG/kcmil)

Diameter (Inches)

Wind Loading (pounds/feet)

Resistance (Ohms)

Ampacity (Amps)

Aluminum Triplex #2 0.780 0.509 0.2931 110 1/0 0.990 0.663 0.1843 150 4/0 1.330 0.898 0.0921 240

Aluminum Quadruplex

1/0 1.290 0.750 0.1843 140 4/0 1.740 0.998 0.0921 230

ACSR #4 0.250 0.168 2.7630 170 #2 0.316 0.212 1.7830 225 1/0 0.398 0.267 1.1530 300 4/0 0.563 0.377 0.6170 460

336.4 0.684 0.458 0.3300 600 653.9 0.953 0.639 0.1710 920

Notes:

1. The resistance of secondary overhead wires are in ohms/1,000 feet.

2. The resistance of primary overhead wires are in ohms/mile.

Table 8-2: Conductor Sizes with Dead End Tensions list each conductor type and size with dead end tensions that Anaheim Public Utilities uses. This data was obtained from construction standard CO 210.

Table 8-2: Conductor Sizes with Dead End Tensions

Conductor Type

Wire Size

(AWG/kcmil) Dead End Tension (pounds)

Aluminum (Triplex or

Quadruplex)

#2 761 1/0 1415 4/0 2780

ACSR #4 458 #2 698 1/0 1070 4/0 2105

336.4 2238 653.9 2700

653.9 (69kV) 2175

REVISION NO. 0

OVERHEAD SYSTEMS

DATE: 03-07-2013

DESIGN MANUAL

DM 8 PAGE 6 OF 11

3.2 Poles

Selection of the proper pole for a project must consider height and strength requirements based on the following:

• Terrain • Number and configuration of distribution circuits • Wind loading • Equipment to be placed on the pole • Possible joint use by other utilities • Minimum conductor ground clearance required by other governmental agencies such as Caltrans or

Flood Control Districts • Fire Hazards

A. Pole Height

Table 8-3: Pole Size and Unguyed Usable Strength list the different pole sizes and strength that Anaheim Public Utilities normally stocks. Other size classes are available on special order only. This data was obtained from construction standard CO 100-3A.

Table 8-3: Pole Size and Unguyed Usable Strength

Pole Height

(feet) Pole Class Setting Depth Ground Line

Circum. (inches)

Top Circum. (inches)

Usable Strength for Light Loading (foot*pounds) Grade “A” (S. F. 4)

Grade “B” (S. F. 3)

40 4 6.0 33.5 21.0 16,025 22,450 45 3 6.5 37.5 23.0 23,225 32,425 50 3 7.0 39.0 23.0 25,250 35,525 55 3 7.5 40.0 23.0 27,350 38,775 60 2 8.0 44.5 25.0 37,725 53,325 65 2 8.5 46.0 25.0 39,775 56,850 75 2 9.5 48.5 25.0 43,850 63,700 80 2 10.0 49.5 25.0 45,925 67,250 85 2 10.5 50.5 25.0 46,250 68,550 90 2 11.0 51.5 25.0 48,250 72,200 95 2 11.0 52.5 25.0 48,800 74,050

100 2 11.0 53.0 25.0 51,175 78,425

B. Pole Strength/Wind Loading

Poles must be capable of supporting horizontal loads caused by wind loading on the pole itself, plus the wind on the conductors supported by the pole, plus dead loads caused by the equipment.

OVERHEAD SYSTEMS

REVISION NO. 0

DATE: 03-07-2013

DESIGN MANUAL

DM 8 PAGE 7 OF 11

Anaheim Public Utilities Guidelines for wind loading are as follows:

• Newly installed pole till 5 years of age – maximum allowable capacity is 95% • 5 – 10 years of age – maximum allowable capacity is 90% • 10 years of age to older – maximum allowable capacity is 80% • Light Loading District – 8 pounds wind load – Anaheim city limits fall under this category • Grade “A” construction – for all joint pole attachments • Grade “B” construction – for primary and secondary conductors only • Setting Depth shall be per Table 8-2: Pole Size and Unguyed Usable Strength

Wind loading calculation will be performed on the following:

• All new pole installations, new construction, and pole replacement • All new additions/upgrades for both primary and secondary conductors including equipment • All new additions/upgrades for both communications and CATV cable wires A wind loading calculation will not be performed on the following: • When an attachment or equipment is being replaced like for like • For additions of risers, switches, fuse holders, crossarms, and so on • When changing existing service wire with new service wire that is the same length. Except

when the replacement service wire exceeds the original length of wire by 25 feet

Table 8-4: Safety Factors for New and In Service Construction per G.O. 95 shows the safety factors to be used when doing wind loading calculations for poles.

Table 8-4: Safety Factors for New and In Service Construction per G.O. 95

Type of Construction Grade “A” Construction Grade “B” Construction

New Construction 4.00 3.00 At Replacement 2.67 2.00

3.3 Crossarms

Wood crossarms with metal braces are installed to support primary conductors. Flat braces are installed where conductors of 4-1/0 ACSR or smaller conductors are to be installed. V-braces are used on crossarms supporting larger conductors.

3.4 Guying

Where mechanical loads to be imposed on poles (bending moment) are greater than can be safely supported by the pole (usable pole strength), additional strength shall be provided by the use of guys. This applies particularly to angles, dead end poles, or where the conductor stresses are sufficiently unbalanced

REVISION NO. 0

OVERHEAD SYSTEMS

DATE: 03-07-2013

DESIGN MANUAL

DM 8 PAGE 8 OF 11

to make guying necessary. The use of anchor rods and downguys are the main method of balancing dead end strain on poles. Sidewalk anchors are used where guy leads of 10 feet or less must be used due to obstacles such as fences, houses, flood controls, and so on. Span guys/arm guys (from pole to pole or from crossarm to pole) can be installed to carry dead end or unbalanced tension to an adjacent pole where proper guy anchoring can be made with a downguy and anchor rod, or to a pole with enough usable pole strength to support the strain. See Section Dm 9: Guying Poles in Overhead Systems for a detailed discussion on this topic.

3.5 Overhead Transformers

Overhead transformers are available in the following sizes:

• 25 kVA • 50 kVA • 75 kVA

Each overhead transformer can be installed three of the same size to form a three phase bank with a capacity of up to 75 kVA, 150 kVA and 225 kVA. Voltages are available at 120/240V, 208Y/120V, or 480Y/277V. If the demand of a customer exceeds the rated capacity of the overhead transformers, a padmount transformer will need to be installed on the customer’s property.


4.1 Example 1: Pole Class

A span of poles needs to be reconductored from 4-1/0 ACSR to 4-336.4 ACSR. Determine if the existing 55 foot poles needs to be replaced with the given data.

Given Data: Grade B Construction – No other joint attachments Length of existing span – 150 feet New Conductors – 336.4 ACSR has a wind loading value of 0.458 pounds per foot per Table 8-1: Conductor Properties with Ampacity 55 foot pole has a setting depth of 7.5 feet per Table 8-3: Pole Size and Unguyed Usable Strength. The conductors will therefore be approximately 47.5 feet above ground.

To determine the total horizontal loading of conductors on a pole, use the following formula: Conductor Load per Foot Number of Span Height Above Total Horizontal Load Size (pounds) Conductors (feet) Ground (foot*pounds) 336.4 ACSR 0.458 X 4 X 150 X 47.5 = 13,053 foot pounds

OVERHEAD SYSTEMS

REVISION NO. 0

DATE: 03-07-2013

DESIGN MANUAL

DM 8 PAGE 9 OF 11

A 55 foot pole has a usable strength of 38,775 foot pounds per Table 8-3: Pole Size and Unguyed Usable Strength using Grade B construction. The poles do not need to be replaced. 4.2 Example 2: Pole Spans

Two new circuits need to be built with 4-336.4 ACSR. Determine the maximum span that a 55 foot pole will support.

Grade B Construction – No other joint attachments New Conductors – 336.4 ACSR has a wind loading value of 0.458 pounds per foot per Table 8-1: Conductor Properties with Ampacity 55 foot pole has a setting depth of 7.5 feet Table 8-3: Pole Size and Unguyed Usable Strength. The conductors will therefore be approximately 47.5 feet for circuit 1 and 41.5 feet for circuit 2 above ground. A 55 foot pole has a usable strength of 38,775 foot pounds per Table 8-3: Pole Size and Unguyed Usable Strength using Grade B construction.

To determine the first calculate the horizontal load per foot of span for each circuit, use the following formula:

Conductor Load per Foot Number of Height Above Horizontal Load per Foot Span Size (pounds) Conductors Ground (pounds) 336.4 ACSR 0.458 X 4 X 47.5 = 87.020 pounds

336.4 ACSR 0.458 X 4 X 41.5 = 76.028 pounds Total = 163.048 pounds

Once the total horizontal load per foot of span has been calculated, then the maximum span is calculated using the following formula:

Maximum Span = Usable Pole Strength / Total Horizontal Load per Foot of Span Maximum Span = 38,775 / 163.048 Maximum Span = 237.81 feet

REVISION NO. 0

OVERHEAD SYSTEMS

DATE: 03-07-2013

DESIGN MANUAL

DM 8 PAGE 10 OF 11

4.3 Example 3: Safety Factor

Consider Example 2: Pole Spans as an existing pole line with an average span of 200 feet. If a telephone company wants to attach a 0.5 inch diameter fiber optic line, determine if the existing pole is adequate with the new additional attachment.

First determine the total horizontal loading of conductors on a pole using the following formula:

Conductor Load per Foot Number of Span Height Above Total Horizontal Load Size (pounds) Conductors (feet) Ground (foot pounds) 336.4 ACSR 0.458 X 4 X 200 X 47.5 = 17,404.0 foot pounds 336.4 ACSR 0.458 X 4 X 200 X 41.5 = 15,205.6 foot pounds

Fiberoptic 0.335 X 1 X 200 X 25.0 = 1,675.00 foot pounds Total = 34,284.6 foot pounds

Next, determine the Moments from Wind on Pole using the following formula:

Moments from Wind on Pole = P*(HOP)2*(C+2c) / 72*π Where: P = Wind Pressure, 8 pounds wind load HOP = Height of Pole Above Ground, 47.5 feet C = Ground Line Circumference, 40 inches c = Top Circumference, 23 inches Moments from Wind on Pole = 8*(47.5)2*(40+2*23) / 72*π Moments from Wind on Pole = 6,862.67 foot pounds Next, determine the Wind Pole Moment using the following formula: Wind Pole Moment = 0.000264*(Afs)*C3

Where: Afs = Average Fiber Stress for Douglas Fir, 8,000 pounds C = Ground Line Circumference, 40 inches Wind Pole Moment = 0.000264*8,000*403

Wind Pole Moment = 135,168 foot pounds

OVERHEAD SYSTEMS

REVISION NO. 0

DATE: 03-07-2013

DESIGN MANUAL

DM 8 PAGE 11 OF 11

Next, determine the Void Moment using the following formula: Void Moment = 0.000264*(Afs)*(C – 2π(S t))3 Where: Afs = Average Fiber Stress for Douglas Fir, 8,000 pounds C = Ground Line Circumference, 40 inches St = Shell Thickness, 1 inch Void Moment = 0.000264*8,000*(40 – 2π(1))3 Void Moment = 80,953.11 foot pounds Next, determine the Safety Factor using the formula: Safety Factor = (Wood Pole Moment – Void Moment) / Moments from Wind on (Conductor + Pole) Safety Factor = (135,168 – 80,953.11) / (34,284.6 + 6,862.67) Safety Factor = 1.3176 Results:

Since the pole is going to be a joint pole, the safety factor needs to be 2.67 for Grade “A” construction with an existing pole that’s in service. In order for the telephone company to attach to the existing pole, the existing pole will need to be replaced with a higher class pole that needs to be special ordered.

Section DM 9

GUYING POLES IN OVERHEAD SYSTEMS


REVISION NO. 0

DATE: 03-07-2013

DESIGN MANUAL

DM 9 PAGE 1 OF 13

SECTION DM 9: GUYING POLES IN OVERHEAD SYSTEMS

TABLE OF CONTENTS No. TITLE PAGE 1.0 SCOPE 3 2.0 DESIGN CRITERIA 3

2.1 DOWN GUYS 4

2.2 SIDEWALK GUYS 9

2.3 SPAN GUYS 10

2.4 ANCHORS AND RODS 11 3.0 SAMPLE CALCULATIONS 11 3.1 Example 1: Size of Anchor Guy Wire 11 3.2 Example 2: Size of Side Anchor Guy Wire 12

REVISION NO. 0


DATE: 03-07-2013

DESIGN MANUAL

DM 9 PAGE 2 OF 13

TABLES No. TITLE PAGE 9-1 Conductor Dead End Tension 4 9-2 Deviation Angles 5 9-3 Conductor Tension for Side Guying Angle Poles 6 9-4 Angle between Guy and Pole 7 9-5 Maximum Conductor Tension for Guy Wires – Grade “A” Construction 8 9-6 Maximum Conductor Tension for Guy Wires – Grade “B” Construction 9 9-7 Angle between Sidewalk Guy and Pole 10

FIGURES No. TITLE PAGE 9-1 Determination of Deviation Angle 5 9-2 Determination of Angle from Guy to Pole 7 9-3 Determination of Angle from Sidewalk Guy to Pole 10


REVISION NO. 0

DATE: 03-07-2013

DESIGN MANUAL

DM 9 PAGE 3 OF 13

DM 9: GUYING POLES IN OVERHEAD SYSTEMS 1.0 SCOPE This Section provides the guidelines for guying wood poles in overhead systems. Where the mechanical loads to be imposed upon the poles are greater than can be safely supported by the poles, additional strength must be provided by the use of guys. This applies particularly to angles, dead ends, and other situations where the conductor stresses are sufficiently unbalanced to make guying necessary. 2.0 DESIGN CRITERIA The use of anchor rods and down guys is the main method of balancing dead end strain on poles. Sidewalk anchors are used where guy leads must be reduced due to obstacles such as fences, buildings, and so on. Span guys/arm guys (from pole to pole or from cross arm to pole) can be installed to carry dead end or unbalanced tension to an adjacent pole where proper guy anchoring can be made with a down guy and anchor rod, or to a pole with enough usable pole strength to support the strain. Planning for location of anchors usually requires field check to verify that there are no hazards, obstacles, or G.O. 95 infractions. Designer should check for and avoid interfering with buildings, driveways, fences, flood control channels, etc. No guys should be attached to trees or other private property except in special cases. In such special cases, permission must be obtained in writing from the owner. Guys attached to anchors must be protected with standard guards if they are exposed to pedestrian or vehicular traffic. Guy wires must be placed and maintained with clearances from conductors or other wires not less than those specified in Tables 1 and 2 of G.O. 95. Where required by the rules of G.O. 95, porcelain strain insulators of the interlocking type must be used in all guys attached to poles. All guys must be attached to poles with special hardware designed for the purpose. Pre-formed guy grips should be used to make up guy heads and strain insulators. Pre-formed or automatic guy grips may be used on the pulling end of guys. When two or more guy wires are installed in close proximity to each other, the attachment of one guy must not overlap that of another, but each must be entirely independent of the other and at least 12 inches apart at the point of attachment to the pole. The point of attachment of the guy to the pole must be as near the level of the cross arms supporting the conductors as practicable to avoid undue bending stress in the pole. Wherever possible, down guy leads (distance from pole to eye of anchor rod) should be equal to or greater than the height of the guy attachment above ground. Down guy leads should never be less than one half of the height of the guy attachment above ground. If it is impracticable to install a satisfactory anchor guy at the dead end pole, the stress may be carried by means of a span guy to an adjacent pole which can be properly guyed. When a guy cannot be carried to ground because of clearance requirements, and there are no other poles or permanent structures to which the guy can be attached, a guy stub pole should be used. A guy stub pole must be sound, at least 8 inches in diameter at top, and of the proper length to insure guy clearance at least as great as those specified in tables 1 and 2 of G.O. 95. Guy stub poles should be guyed to anchors in the same manner as line poles whenever possible.

REVISION NO. 0


DATE: 03-07-2013

DESIGN MANUAL

DM 9 PAGE 4 OF 13

Guying is accomplished by one of the three methods explained below. Designers should also consult Section CO 100 of the Construction Standards for more details and additional information. All guys are installed and adjusted before the conductors are strung so that the pole or cross arm will stand in its proper position when the entire unbalanced stress is taken by the guy. Use the table in Construction Standard CO 130-10 to determine length of guy wires.

2.1 Down Guys

Down guys are the most common method used for guying. The following steps outline how to determine the proper number and size of guy wires to be used:

A. Determine the unbalanced conductor strain on the pole. To determine the strain caused by

dead ended conductors, add the tensions for all dead ended conductors. Table 9-1 lists dead end tensions for each conductor type and size. This data was obtained from construction standard CO 210. The dead end tension must be multiplied by the number of conductors to determine the total dead end tension for guying.

Table 9-1: Conductor Dead End Tension

Conductor Type

Wire Size (AWG or

kcmil)

Dead End Tension (pounds)

Aluminum (Triplex or

Quadruplex)

#2 761 1/0 1415 4/0 2780

ACSR #4 458 #2 698 1/0 1070 4/0 2105

336.4 2238 653.9 2700

653.9 (69kV) 2175


REVISION NO. 0

DATE: 03-07-2013

DESIGN MANUAL

DM 9 PAGE 5 OF 13

To determine the resultant strain on an angle pole, first calculate the deviation angle of the conductors by measuring distances “A” and “B” per Figure 9-1: Determination of Deviation Angle, and using the formula:

Deviation Angle = atan (B / A)

Figure 9-1: Determination of Deviation Angle

For example, if A = 50 feet and B = 30 feet, then:

Deviation Angle = atan (30 / 50) = atan 0.60 = 30.96 deg

Table 9-2: Deviation Angles shows rounded values of some typical deviation angles for five foot increments of “A” between 20 and 60 feet, and their corresponding distances of “B”. The formula used to obtain these values is the Deviation Angle formula.

Table 9-2: Deviation Angles

Distance “A” (feet) Distance “B” (feet)

20 4 5 7 9 12 14 17 20 24 29 35 25 4 7 9 12 14 18 21 25 30 36 43 30 5 8 11 14 17 21 25 30 36 43 52 35 6 9 13 16 20 25 29 35 42 50 61 40 7 11 15 19 23 28 34 40 48 57 69 45 8 12 16 21 26 32 38 45 54 64 78 50 9 13 18 23 29 35 42 50 60 71 87 55 10 15 20 26 32 39 46 55 66 79 95 60 11 16 22 28 35 42 50 60 72 86 104

Deviation Angle 10˚ 15˚ 20˚ 25˚ 30˚ 35˚ 40˚ 45˚ 50˚ 55˚ 60˚

REVISION NO. 0


DATE: 03-07-2013

DESIGN MANUAL

DM 9 PAGE 6 OF 13

Once the deviation angle is determined, locate it on Table 9-3: Conductor Tension for Side Guying Angle Poles to determine the resultant side tension for the conductor size/type used. For example, one 336.4 ACSR conductor at a deviation angle of 30 degrees has a side tension of 1,158 pounds.

The values in Table 9-3: Conductor Tension for Side Guying Angle Poles was obtained using vector formulas with the summation of the “X” component and “Y” component of each conductor based on the deviation angles.

X Component = Tension*Cos(0˚) – Tension*Cos(Deviation Angle) Y Component = Tension*Sin(0˚) – Tension*Sin(Deviation Angle) Resultant Tension = √((X Component)2 + (Y Component)2)

As an example, let’s assume a 1/0 conductor has deviation angle of 60 degrees. The tension to be used can be pulled from Table 9-1: Conductor Dead End Tension. A 1/0 conductor has a dead end tension of 1,415 pounds.

X Component = Tension*Cos(0˚) – Tension*Cos(Deviation Angle) X Component = 1,415*Cos(0˚) – 1,415*Cos(60˚) X Component = 707.5 pounds Y Component = Tension*Sin(0˚) – Tension*Sin(Deviation Angle) Y Component = 1,415*Sin(0˚) – 1,415*Sin(60˚) Y Component = – 1,225.4259 Resultant Tension = √((X Component)2 + (Y Component)2) Resultant Tension = √((707.5)2 + (– 1225.4259)2) Resultant Tension = 1,415 pounds

Table 9-3: Conductor Tension for Side Guying Angle Poles

Conductor Type and Size Deviation Angles (degrees) 10 20 30 40 50 60 70

Tension (pounds) Aluminum Triplex or

Quadruplex 1/0 247 491 732 968 1196 1415 1623 4/0 485 965 1439 1902 2350 2780 3189

ACSR #4 80 159 237 313 387 458 525 #2 122 242 361 477 590 698 801 1/0 187 372 554 732 904 1070 1227 4/0 367 731 1090 1440 1779 2105 2415

336.4 390 777 1158 1531 1892 2238 2567 653.9 471 938 1398 1847 2282 2700 3097


REVISION NO. 0

DATE: 03-07-2013

DESIGN MANUAL

DM 9 PAGE 7 OF 13

B. Determine the angle created by the guy to the pole from Table 9-4: Angle between Guy and Pole, using the height of the guy attachment to ground and the guy lead per Figure 9-2: Determination of Angle from Guy to Pole.

Table 9-4: Angle between Guy and Pole shows rounded values of some typical leads based on 5 degree angle increments. The formula used to obtain these values is Lead = Attachment Height*Tan(Angle).

Figure 9-2: Determination of Angle from Guy to Pole

Table 9-4: Angle between Guy and Pole

Height (feet) (Guy to Ground)

Lead (feet) (Pole to Anchor)

20 4 5 7 9 12 14 17 20 24 29 35 25 4 7 9 12 14 18 21 25 30 36 43 30 5 8 11 14 17 21 25 30 36 43 52 35 6 9 13 16 20 25 29 35 42 50 61 40 7 11 15 19 23 28 34 40 48 57 69 45 8 12 16 21 26 32 38 45 54 64 78 50 9 13 18 23 29 35 42 50 60 71 87 55 10 15 20 26 32 39 46 55 66 79 95 60 11 16 22 28 35 42 50 60 72 86 104 65 11 17 24 30 38 46 55 65 77 93 113 70 12 19 25 33 40 49 59 70 83 100 121 75 13 20 27 35 43 53 63 75 89 107 130 80 14 21 29 37 46 56 67 80 95 114 139 85 15 23 31 40 49 60 71 85 101 121 147 90 16 24 33 42 52 63 76 90 107 129 156

Angle (Guy to Pole)

10˚ 15˚ 20˚ 25˚ 30˚ 35˚ 40˚ 45˚ 50˚ 55˚ 60˚

REVISION NO. 0


DATE: 03-07-2013

DESIGN MANUAL

DM 9 PAGE 8 OF 13

C. Determine the number and size of guy wires required to support the conductor strain from Table 9-5: Maximum Conductor Tension for Guy Wires – Grade “A” Construction and Table 9-6: Maximum Conductor Tension for Guy Wires – Grade “B” Construction. Values of maximum safe conductor tension in this table have been calculated from ultimate conductor tension divided by safety factor of 2 and 1.5 respectively (reference Table 24, G.O. 95). One guy or a combination of guys may be required.

Example: A single 5/16” guy wire installed at an angle of 45 degrees between the pole and the guy is capable of supporting a conductor tension of 2,245 pounds at grade “A” construction.

Table 9-5: Maximum Conductor Tension for Guy Wires – Grade “A” Construction and Table 9-6: Maximum Conductor Tension for Guy Wires – Grade “B” Construction shows rounded values of some typical maximum conductor tensions based on 5 degree angle increments. The formula used to obtain these values is Tension = Level Tension*Sin(Angle).

Table 9-5: Maximum Conductor Tension for Guy Wires – Grade “A” Construction

Angle

(Guy to Pole) Guy Size

5/6” 7/16” 5 277 632

10 551 1259 15 822 1876 20 1086 2480 25 1342 3064 30 1588 3625 35 1821 4158 40 2041 4660 45 2245 5127 50 2432 5554 55 2601 5939 60 2750 6279

Level Overhead Guy

3175* 7250**

* Ultimate conductor tension (6,350 pounds) divided by Safety Factor of 2 (from Table 24, G.O.95). ** Ultimate conductor tension (14,500 pounds) divided by Safety Factor of 2 (from Table 24, G.O.95).


REVISION NO. 0

DATE: 03-07-2013

DESIGN MANUAL

DM 9 PAGE 9 OF 13

Table 9-6: Maximum Conductor Tension for Guy Wires – Grade “B” Construction

Angle (Guy to Pole)

Guy Size 5/6” 7/16”

5 369 843 10 735 1679 15 1096 2502 20 1448 3306 25 1789 4085 30 2117 4833 35 2428 5545 40 2721 6214 45 2993 6835 50 3243 7405 55 3468 7918 60 3666 8372

Level Overhead Guy

4233 9667

* Ultimate conductor tension (6,350 pounds) divided by Safety Factor of 1.5 (from Table 24, G.O.95). ** Ultimate conductor tension (14,500 pounds) divided by Safety Factor of 1.5 (from Table 24, G.O.95).

2.2 Sidewalk Guys

Sidewalk guys are installed where reduced guy lead is required because of obstacles or obstructions, for example, fences, streets, buildings, and so on. In designing sidewalk guys, a minimum clearance of 5 feet behind the curb must be maintained in order to prevent vehicle contact. All locations of sidewalk guy installation must have one guy guard per anchor. The length of strut used for sidewalk guy should not exceed 12 feet. Maximum of 2 guy wires are allowed on any one strut for a sidewalk anchor. The following steps outline how to determine the proper number and size of guy wires to be used:

A. Determine the unbalanced conductor strain on the pole per 2.1.A above.

B. Determine the angle created by the guy to the pole from Table 9-7: Angle between Sidewalk

Guy and Pole, using the height of the guy attachment to strut, and the guy lead (length of strut), per Figure 9-3: Determination of Angle from Sidewalk Guy to Pole. For example, the angle between the guy and the pole for a sidewalk guy wire attached at 35 feet above an 8-foot strut is 13 degrees.

Table 9-7: Angle between Sidewalk Guy and Pole shows typical angles based on 5 foot height increments. The formula used to obtain these values is Angle = atan (Queen Post Length / Attachment Height)

REVISION NO. 0


DATE: 03-07-2013

DESIGN MANUAL

DM 9 PAGE 10 OF 13

Table 9-7: Angle between Sidewalk Guy and Pole

Height (feet) (Guy Attachment to Queen Post)

Length of Queen Post 5 6 7 8 9 10 11 12

10 27 31 35 39 42 45 48 50 15 18 22 25 28 31 34 36 39 20 14 17 19 22 24 27 29 31 25 11 13 16 18 20 22 24 26 30 9 11 13 15 17 18 20 22 35 8 10 11 13 14 16 17 19 40 7 9 10 11 13 14 15 17 45 6 8 9 10 11 13 14 15 50 6 7 8 9 10 11 12 13 55 5 6 7 8 9 10 11 12 60 5 6 7 8 9 9 10 11 65 4 5 6 7 8 9 10 10 70 4 5 6 7 7 8 9 10

Figure 9-3: Determination of Angle from Sidewalk Guy to Pole

C. Determine the number and size of guy wires required to support the conductor strain from Table 9-5: Maximum Conductor Tension for Guy Wires – Grade “A” Construction and Table 9-6: Maximum Conductor Tension for Guy Wires – Grade “B” Construction per 2.1.C above.

2.3 Span Guys

Span guys or arm guys are installed from pole to pole or from cross arm to pole when it is not feasible to install a down guy or sidewalk guy. The following steps outline how to determine the proper number and size of guy wires to be used:


REVISION NO. 0

DATE: 03-07-2013

DESIGN MANUAL

DM 9 PAGE 11 OF 13

A. Determine the unbalanced conductor strain on the pole or cross arm per 2.1.A above.

B. Determine the number and size of guy wires required to support the conductor strain from Table 9-5: Maximum Conductor Tension for Guy Wires – Grade “A” Construction and Table 9-6: Maximum Conductor Tension for Guy Wires – Grade “B” Construction per 2.1.C above. Use the row for “Level (Overhead Guy)”.

C. Usable pole strength or down guy tensions may then be calculated using the conductor dead

end tension.

2.4 Anchors and Rods

Any anchor and rod specified in the guying design must exceed the total working strength of the guy wires attached to them. The maximum working strength of a guy wire is equal to the value listed in Table 9-5: Maximum Conductor Tension for Guy Wires – Grade “A” Construction and Table 9-6: Maximum Conductor Tension for Guy Wires – Grade “B” Construction for a guy wire installed at level position (use the row for “Level (Overhead Guy)”). The working strengths are 3,175 pounds for grade “A” construction and 4,233 pounds for grade “B” construction for a 5/16” guy wire, and 7,250 pounds for grade “A” construction and 9,667 pounds grade “B” construction for a 7/16” guy wire.

APU installs only one type of anchor. Power Installed Screw Anchor is installed with the auger shaft of the line truck. Shear pins on the installation tool are used to determine the holding strength of this anchor. The standard screw anchor used by APU is an 11-5/16” single helix anchor with a 1-3/8” hub, 1” rod, and triple eye nut. It can be used for maximum guy wire tension of up to 18,000 pounds but it is recommended to keep each anchor limited to working load of 11,500 pounds.


3.1 Example 1: Size of Anchor Guy Wire

Given the figure below, a 4/0 aluminum triplex secondary dead end, to be anchor guyed, with a lead of 20 feet the guy attached to the pole 30 feet above the ground (height), find the size of guy required for Grade “B” construction.

REVISION NO. 0


DATE: 03-07-2013

DESIGN MANUAL

DM 9 PAGE 12 OF 13

A. Find in Table 9-1: Conductor Dead End Tension, the tension for 4/0 aluminum triplex conductor.

Answer: 2,780 pounds

B. Next find in Table 9-4: Angle between Guy and Pole, the guy angle most nearly corresponding

to a height of 30 feet and a lead of 20 feet.

Answer: 35 degrees

C. Then find in Table 9-6: Maximum Conductor Tension for Guy Wires – Grade “B” Construction, the required size for guy to hold a conductor tension of (a) 2,780 pounds at a guy angle of (b) 35 degrees using the next larger figure above 2,780 pounds. In this case the next larger figure in the column for a 35 degree angle is 5,545 pounds.

Answer: Since 5/16" can only safely support 2,428 pounds, one 7/16" guy wire with a maximum conductor tension of 5,545 pounds should be used.

3.2 Example 2: Size of Side Anchor Guy Wire

Given the figure below, (4) 336.4 kcmil ACSR distribution conductors with a deviation angle of 30 degrees in the line, find the size of guy to hold the angle pole with a height of 45 feet and a lead of 20 feet, for both Grade “A” and “B” construction.

A. Find in Table 9-3: Conductor Tension for Side Guying Angle Poles, the resultant side pull for (4) 336.4 kcmil ACSR conductors at a deviation angle of 30 degrees. 3*1,158 = 4,632 pounds.

Answer: 4,632 pounds


REVISION NO. 0

DATE: 03-07-2013

DESIGN MANUAL

DM 9 PAGE 13 OF 13

B. Next find in Table 9-4: Angle between Guy and Pole, the guy angle most nearly corresponding to a height of 45 feet and a lead of 20 feet.

Answer: 25 degrees

C. For a Grade A construction, find in Table 9-5: Maximum Conductor Tension for Guy Wires –

Grade “A” Construction, the required size of guy for a resultant pull of (a) 4,632 pounds and a guy angle of (b) 25 degrees, using the next larger tension above 4,632 pounds. In this case, the next tension or combination of tensions in the 25 degree column is 3,064 + 3,064 pounds.

Answer: Use (2) 7/16” guy

D. For Grade B construction, find in Table 9-6: Maximum Conductor Tension for Guy Wires –

Grade “B” Construction, the required size of guy for a resultant pull of (a) 4,632 pounds and a guy angle of (b) 25 degrees, using the next larger tension above 4,632 pounds. In this case, the next tension or combination of tensions in the 25 degree column is 1,789 + 4,085 pounds.

Answer: Use (1) 5/16” guy and (1) 7/16” guy

Section DM 10

FORMULAS

TYPICAL FORMULAS

REVISION NO. 0

DATE: 03-07-2013

DESIGN MANUAL

DM 10 PAGE 1 OF 10

SECTION DM 10: TYPICAL FORMULAS

TABLE OF CONTENTS No. TITLE PAGE 1.0 FORMULA LEGEND 3 2.0 SINGLE PHASE FORMULAS 3 3.0 THREE PHASE FORMULAS 4 4.0 POWER FACTOR 5 4.1 Lagging Power Factor (current lags voltage) 5 4.2 Leading Power Factor (current leads voltage) 5 5.0 FACTORS 6 6.0 VOLTAGE DROP FORMULAS 6 6.1 Single Phase Voltage Drop 6 6.2 Three Phase Voltage Drop 7 7.0 CABLE PULLING FORMULAS 7 8.0 OVERHEAD AND GUYING FORMULAS 8 9.0 SAMPLE CALCULATIONS 9 9.1 Single Phase 9 9.2 Three Phase 10 9.3 Horsepower to kVA 10

REVISION NO. 0

TYPICAL FORMULAS

DATE: 03-07-2013

DESIGN MANUAL

DM 10 PAGE 2 OF 10

TABLES No. TITLE PAGE 10-1 Factors for Secondary Voltages 6 10-2 Factors for Single Phase Primary Voltages 6 10-3 Factors for Three Phase Primary Voltages 6

TYPICAL FORMULAS

REVISION NO. 0

DATE: 03-07-2013

DESIGN MANUAL

DM 10 PAGE 3 OF 10

DM 10: TYPICAL FORMULAS 1.0 FORMULA LEGEND atan = Arc Tangent cos = Cosine I = Current in Amperes V = Voltage in Volts

PF = Power Factor W = Watts kW = Kilo Watts VA = Volt Amperes

kVA = Kilo Volt Amperes kVar = Kilo Vars

HP = Horsepower eff = Efficiency 1.732 = Square Root of 3 2.0 SINGLE PHASE FORMULAS

I = W / (V*PF) = (kW*1,000) / (V*PF) = (kW*1,000) / V = (HP*746) / (V*PF*eff)

V = W / (I*PF) = (kW*1,000) / (I*PF) = (kW*1,000) / I = (HP*746) / (I*PF*eff)

W = V*I*PF

kW = (V*I*PF) / 1,000 = kVA*PF = (HP*746) / (1,000*eff)

VA = V*I

kVA = (V*I) / 1,000 = kW / PF = (HP*746) / (1,000*PF*eff)

PF = W / VA = kW / kVA

HP = (V*I*PF*eff) / 746 Notes:

1. Eff = Efficiency. Assume 90% if actual value is not known

REVISION NO. 0

TYPICAL FORMULAS

DATE: 03-07-2013

DESIGN MANUAL

DM 10 PAGE 4 OF 10

3.0 THREE PHASE FORMULAS

I = W / (V*PF*1.732) = (kW*1,000) / (V*PF*1.732) = (kW*1,000) / (V*1.732) = (HP*746) / (V*PF*eff*1.732)

V = W / (I*PF*1.732) = (kW*1,000) / (I*PF*1.732) = (kW*1,000) / (I*1.732) = (HP*746) / (I*PF*eff*1.732)

W = V*I*PF*1.732

kW = (V*I*PF*1.732) / 1,000 = kVA*PF = (HP*746) / (1,000*eff)

VA = V*I*1.732

kVA = (V*I*1.732) / 1,000 = kW / PF = (HP*746) / (1,000*PF*eff)

PF = W / VA = kW / kVA

HP = (V*I*PF*eff*1.732) / 746 Notes:

1. Eff = Efficiency. Assume 90% if actual value is not known

TYPICAL FORMULAS

REVISION NO. 0

DATE: 03-07-2013

DESIGN MANUAL

DM 10 PAGE 5 OF 10

4.0 POWER FACTOR Power Factor must be considered in the determination of transformer and cable size. The term “Power Factor” represents the ration of true power (applied power) to the apparent power (amount that would actually be available for application if voltage and current were in phase with each other). Graphically, the relationships between true power, apparent power, and reactive power are as follows:

4.1 Lagging Power Factor (current lags voltage)

4.2 Leading Power Factor (current leads voltage)

The power factor angle is the angle of lag or lead between the current and voltage. A lagging current is produced by serving loads involving magnetizing of motor fields. A leading current is produced by serving loads which have capacitance such as capacitors or cable. Loads which are of resistive nature such as heating and incandescent lighting have currents which are in phase with the voltage and will not produce a lagging or leading current. True power and apparent power will be the same when the load is all resistive.

REVISION NO. 0

TYPICAL FORMULAS

DATE: 03-07-2013

DESIGN MANUAL

DM 10 PAGE 6 OF 10

5.0 FACTORS The following is a list of factors that can be used to compute amperage of kVA or MVA. These values were obtained using the formulas under Section 2: SINGLE PHASE FORMULAS and Section 3: THREE PHASE FORMULAS.

Table 10-1: Factors for Secondary Voltages

Voltage Factor 120V 1Ø 8.33 Amps per kVA 240V 1Ø 4.17 Amps per kVA 277V 1Ø 3.61 Amps per kVA 208V 3Ø 2.78 Amps per kVA 240V 3Ø 2.41 Amps per kVA 480V 3Ø 1.20 Amps per kVA

Table 10-2: Factors for Single Phase Primary Voltages

Nominal Voltage Typical System Voltage Factor

6.9kV 7.2kV 1Ø 139 Amps per MVA 12kV 12.47 1Ø 80 Amps per MVA

Table 10-3: Factors for Three Phase Primary Voltages

Nominal Voltage Typical System Voltage Factor

12kV 12.47 3Ø 46 Amps per MVA 6.0 VOLTAGE DROP FORMULAS See Section Dm 6: Voltage Drop, Flicker, and Short Circuit Duty for a detailed discussion on this topic.

6.1 Single Phase Voltage Drop VD = (2*L*R*I) / 1,000 %VD = (VD / VS)*100 Where: VD = Voltage Drop %VD = Percentage of Voltage Drop VS = Source Voltage L = One way length of circuit feeder R = Resistance factor per NEC Chapter 9, Table 8, in ohm/kft I = Load current in Amperes

TYPICAL FORMULAS

REVISION NO. 0

DATE: 03-07-2013

DESIGN MANUAL

DM 10 PAGE 7 OF 10

6.2 Three Phase Voltage Drop VD = (2*L*R*I*(√3 / 2)) / 1,000 or (√3*L*R*I) / 1,000 %VD = (VD / VS)*100 Where: VD = Voltage Drop %VD = Percentage of Voltage Drop VS = Source Voltage L = One way length of circuit feeder R = Resistance factor per NEC Chapter 9, Table 8, in ohm/kft I = Load current in Amperes 7.0 CABLE PULLING FORMULAS See Section Dm 7: Cable Pulling and Splicing for a detailed discussion on this topic.

A. The maximum stresses must not be exceeded when pulling a cable:

1. The maximum tension shall not exceed 0.008 times CM (Circular Mil) area when pulled with a pulling eye attached to the copper or aluminum conductors.

Tm = 0.008*N*CM Where: Tm = maximum tension in pounds N = number of cable in run CM = circular mil area of each conductor

B. The pulling tension in a given horizontal conduit section may be calculated from the following:

1. For a straight section, the pulling tension is equal to the length of the conduit run multiplied

by the weight per foot of the cable and the coefficient of friction, thus:

T = L*W*F Where: T = total pulling tension L = length of conduit run in feet W = weight of cable in pounds per foot f = coefficient of friction

REVISION NO. 0

TYPICAL FORMULAS

DATE: 03-07-2013

DESIGN MANUAL

DM 10 PAGE 8 OF 10

2. For conduits having curved sections, the following formula applies:

Tout = Tin efa Where: Tout = tension out of the curved section Tin = tension into the curved section e = 2.718 (naperian logarithm base) f = coefficient of friction a = angle of the curved section in radians

8.0 OVERHEAD AND GUYING FORMULAS See Section Dm 8: Overhead Systems for a detailed discussion on this topic. Total Horizontal Load = Conductor Size*Load per Foot*Number of Conductors*Span*Height Above Ground Maximum Span = Usable Pole Strength / Total Horizontal Load per Foot of Span Moments from Wind on Pole = P*(HOP)2*(C+2c) / 72*π Where: P = Wind Pressure, 8 pounds wind load HOP = Height of Pole Above Ground C = Ground Line Circumference c = Top Circumference Wind Pole Moment = 0.000264*(Afs)*C3

Where: Afs = Average Fiber Stress for Douglas Fir, 8,000 pounds C = Ground Line Circumference Void Moment = 0.000264*(Afs)*(C – 2π(S t))3

Where: Afs = Average Fiber Stress for Douglas Fir, 8,000 pounds C = Ground Line Circumference St = Shell Thickness, 1 inch Safety Factor = (Wood Pole Moment – Void Moment) / Moments from Wind on (Conductor + Pole)

TYPICAL FORMULAS

REVISION NO. 0

DATE: 03-07-2013

DESIGN MANUAL

DM 10 PAGE 9 OF 10

See Section Dm 9: Guying Poles in Overhead Systems for a detailed discussion on this topic. Deviation Angle = atan (B / A) X Component = Tension*Cos(0˚) – Tension*Cos(Deviation Angle) Y Component = Tension*Sin(0˚) – Tension*Sin(Deviation Angle) Resultant Tension = √((X Component)2 + (Y Component)2) Lead = Attachment Height*Tan(Angle) Tension = Level Tension*Sin(Angle) Angle = atan (Queen Post Length / Attachment Height) 9.0 SAMPLE CALCULATIONS

9.1 Single Phase

A. Determine the full load secondary amps for 75kVA, 120/240V, 1Ø transformer.

Using Formula: I = (kVA*1,000) / V = (75*1,000) / 240 = 312.5 A

Using Factor: I = kVA*Factor = 75*4.17 = 312.5 A

B. Determine the kVA for 160 Amps at 240V, 1Ø.

Using Formula: kVA = (V*I) / 1,000 = (160*240) / 1,000 = 38.4 kVA

Using Factor: kVA = I / Factor = 160 / 4.17 = 38.4kVA

C. Determine the full load primary amps for a 6.9kV single phase radial with 225kVA of transformation.

Using Formula: I = (kVA*1,000) / V = (225*1,000) / 7,200 = 31.25 A

Using Factor: I = MVA*Factor = .225*139 = 31.25 A

REVISION NO. 0

TYPICAL FORMULAS

DATE: 03-07-2013

DESIGN MANUAL

DM 10 PAGE 10 OF 10

9.2 Three Phase

A. Determine the full load secondary amps for 225kVA, 120/208V, 3Ø transformer.

Using Formula: I = (kVA*1,000) / (V*1.732) = (225*1,000) / (208*1.732) = 624.56 A

Using Factor: I = kVA*Factor = 225*2.78 = 624.56 A

B. Determine the full load primary amps for a 2,500kVA, 12KV, 3Ø transformer.

Using Formula: I = (kVA*1,000) / (V*1.732) = (2,500*1,000) / (12,470*1.732) = 115.75 A

Using Factor: I = MVA*Factor = 2,500*46 = 115.75 A

C. Determine the kVA for 60 Amps at 12kV, 3Ø

Using Formula: kVA = (V*I*1.732) / 1,000 = (12,470*60*1.732) / 1,000 = 1,295.88 kVA

Using Factor: kVA = I / Factor = 60 / 46 = 12.9588 MVA

9.3 Horsepower to kVA

A. Determine the kVA and amps for a 200HP motor served at 480V, 3Ø with a given power factor of 92%. Assume efficiency at 90%.

Using Formula: kVA = (HP*746) / (1,000*PF*eff) = (200*746) / (1,000*0.92*0.90)

kVA = 180.19 kVA

Using Formula: I = (HP*746) / (V*PF*eff*1.732) = (200*746) / (480*0.92*0.90*1.732) I = 216.75 A

Section DM 11

UNDERGROUND STRUCTURE AND

EQUIPMENT APPLICATION GUIDELINES

UNDERGROUND STRUCTURE AND EQUIPMENT APPLICATION GUIDELINES

REVISION NO. 1

DATE: 03-29-2021

DESIGN MANUAL

DM 11 PAGE 1 OF 18

SECTION DM 11: UNDERGROUND STRUCTURE AND EQUIPMENT APPLICATION GUIDELINES

TABLE OF CONTENTS No. TITLE PAGE 1.0 SCOPE 3 2.0 DESIGN CRITERIA 3 2.1 Structure Type 3 2.2 Structure Location 3 3.0 STRUCTURE APPLICATION GUIDELINES 4 4.0 EQUIPMENT APPLICATION GUIDELINES 7

REVISION NO. 1


DATE: 03-29-2021

DESIGN MANUAL

DM 11 PAGE 2 OF 18

TABLES No. TITLE PAGE 11-1 Secondary/Service and Street Light Pull Boxes 4 11-2 Primary Splice Boxes 5 11-3 Padmount Equipment Structures 5 11-4 Subsurface Equipment Structures 6 11-5 Distribution Vaults with Cable and Equipment Requirements 6

FIGURES No. TITLE PAGE 11-1 SDS Switch Applications - Looped Feed 7 11-2 SDS Switch Applications - Radial Feed 8 11-3 Padmount Switch Applications – PMH-9 9 11-4 Padmount Switch Applications – PMH-10 10 11-5 Padmount Switch Applications – PMH-11 11 11-6 Padmount Switch Applications – PMH-12 12 11-7 Padmount Switch Applications – PMH-13 13 11-8 Padmount Switch Applications – PMV-9 14 11-9 Padmount Switch Applications – PMV-10 15 11-10 Subsurface Switch Applications – UDS-9 & UDS-10 16 11-11 Subsurface Switch Applications – UDS-11 & UDS-12 17


REVISION NO. 1

DATE: 03-29-2021

DESIGN MANUAL

DM 11 PAGE 3 OF 18

DM 11: UNDERGROUND STRUCTURE AND EQUIPMENT APPLICATION GUIDELINES 1.0 SCOPE This section provides the criteria to be used in selecting the proper size structure and equipment that will adequately accommodate new installations and also to help determine equipment that may be installed in existing structures. Tables are provided that identify typical applications and the maximum equipment/cable recommended for each structure type and size. 2.0 DESIGN CRITERIA Structures should be installed to accommodate anticipated growth and system needs for the next ten years.

2.1 Structure Type

Tub-type structures are standard for vaults, manholes, surface operable enclosures, and padmounted switch structures used for feeder and commercial/Industrial systems.

Padmounted or surface operable equipment and structures should be utilized where conditions permit. Vaults should normally be used to house switches in full traffic areas only.

2.2 Structure Location

The preferred location for structures is in non-traffic areas with adequate truck access which is typically around 16 feet per truck for any transportation, operation, and maintenance that may be needed. Truck access may have to be doubled if the equipment is heavier than typical equipment such as 2,500 kVA padmount transformers where trucks will have to stay within a certain safe working distance from the transformer pad to lift the transformers. The second choice would be in light traffic areas (parking lot or areas not subject to truck traffic). Full traffic locations are least desirable.

In all cases, consideration must be given to the following when determining structure locations:

A. Clearance from other utilities’ substructures.

B. Traffic patterns and traffic control requirements.

C. Visibility for vehicles when using padmounted equipment.

D. Aesthetics in relation to development plans.

E. Governmental restrictions and regulations.

REVISION NO. 1


DATE: 03-29-2021

DESIGN MANUAL

DM 11 PAGE 4 OF 18

3.0 STRUCTURE APPLICATION GUIDELINES Structures selected should be the smallest/least expensive structures that will accommodate the anticipated ten year need for cable/equipment. Tables 11-1 through 11-5 may be used to determine the maximum cable/equipment that may be installed in various structure types and sizes. These tables are based on requirements for working space, cable shaping, and equipment mounting. The tables should be followed when planning new structure installations or adding cable/equipment to existing structures. Unusual circumstances may warrant deviating from the tables. Existing structures with more cable/equipment than allowed by the tables should not be rebuilt merely because they do not meet the new guidelines. Specific circumstances may justify deviating from the tables.

Table 11-1: Secondary/Service and Street Light Pull Boxes

Dimensions (W X L X D)

Material Typical Applications Maximum Conduit Runs

Maximum Cable Size

13” X 24” X 15” Plastic Residential/Street Light 4 Runs in Conduit

350

13” X 24” X 18” Concrete/Fiberglass Reinforced Residential/Street Light 4 Runs in

Conduit 350

17” X 30” X 18” Concrete/Fiberglass Reinforced Residential/Commercial 6 Runs in

Conduit 350

Notes:

1. Secondary/Service pull boxes are intended to be used for 120/240 volt single phase cables only.

2. A run refers to any set of cables that enters the structure from any direction.

3. Fiberglass Reinforced pull boxes may be used in driveways or parking lots, on private

property, that are not subject to truck traffic.

4. For 13" X 24" residential pull boxes, two runs of 350 kcmil cable may be used. All other cable runs shall be 4/0 or smaller.

5. For 17" X 30" pull boxes, three runs of 350 kcmil cable may be used. All other cable runs

shall be 4/0 or smaller.


REVISION NO. 1

DATE: 03-29-2021

DESIGN MANUAL

DM 11 PAGE 5 OF 18

Table 11-2: Primary Splice Boxes

Dimensions (W X L X D)

Material Typical Applications Maximum Conduit Runs

Maximum Cable Runs

24” X 36” X 30” Concrete Residential/Commercial 6.9kV or 12 kV (1) 3-4/0 Cable 30” X 48” X 30” Concrete Residential/Commercial 6.9kV or 12 kV (2) 3-4/0 Cable

Notes:

1. A run refers to any set of cables that enter the vault from any direction

2. These splice boxes are intended to be used for primary cable only. For secondary cable

only, use Table 11-1: Secondary/Service and Street Light Pull Boxes.

3. Parkway and light traffic pull boxes are available in all sizes.

4. Intercept pull boxes are available in all sizes.

Table 11-3: Padmount Equipment Structures

Structure Applicable Equipment Padmount Transformers

48” x 54” Pad (Concrete/Polymer) 25-167 kVA, 1Ø, 3 Wire Transformer 6’ X 8’ or 6’ X 8’-6” Pad with 4’ X 7’ Cable Box 75-150 kVA, 3Ø, 4 Wire Transformer

8’ X 10’ Pad with 5’ X 8’-6” Cable Box 300-2,500 kVA, 3Ø, 4 Wire Transformer 10’ X 12’ Pad with 5’ X 8’-6” Cable Box 2,500-3,750 kVA, 3Ø, 4 Wire Transformer

Switches 34” x 40” Pad 6.9 kV, 1Ø Fuse Cabinet

4’ X 4’-6” Pad with 2’ X 3’ Cable Box 12 kV, 3Ø PMH-3 or PMH-4 Switch 6’ X 9’-6” Pad with 5’ X 8’-6” Cable Box 12 kV, 3Ø PMH-9 to PMH-13 Switch

5’ X 10’-6” X 7’ Vault (Tub Type) 12 kV, 3Ø PMH-9 to PMH-13 Switch 8’ X 10’ X 7’ Vault PMV Switch

Capacitor 72” X 94” Pad or 80” X 96” Field Poured Padmount Capacitor

Notes:

1. The 5’ X 10’-6” X 7’ Vault (Tub Type) is the preferred structure type in installing PMH-9 to

PMH-13 padmount switches.

REVISION NO. 1


DATE: 03-29-2021

DESIGN MANUAL

DM 11 PAGE 6 OF 18

Table 11-4: Subsurface Equipment Structures

Structure Applicable Equipment Submersible Transformers

42” Internal Diameter x 6’ Concrete 25-100 kVA, 1Ø, 3 Wire Transformer 38” Internal Diameter x 6’ Plastic 25-100 kVA, 1Ø, 3 Wire Transformer

Switches 4’ X 4’ Concrete Vault 12 kV Junctions

5’ X 5’ Vault with 18” Neck Extension 200A Solid Dielectric 3-Way Switch (SDS) 8’ X 14’ X 9’-4” (1) 600A Solid Dielectric 4-Way Switch (UDS) 8’ X 20’ X 9’-4” (2) 600A Solid Dielectric 4-Way Switch (UDS)

Notes:

1. The 38” internal diameter x 6’ plastic transformer holeliner shall be used in landscape areas

only. The 42” internal diameter x 6’ concrete transformer holeliner is the preferred structure type in installing submersible transformers.

2. A 5’ X 5’ concrete vault with 12” and 6” neck extensions (total of 18 inches of neck extension)

is the required structure for a 200A solid dielectric 3-way switch.

Table 11-5: Distribution Vaults with Conduit and Equipment Requirements

Vault Size Maximum Number of 6” Conduits

Maximum Number of 4” Conduits

Maximum Number of UDS Switches

4’ X 7’ X 6’-6” (see Note 1)

4 4 0

5’ X 8’-6” X 6’-6” (see Note 1)

4 4 0

8’ X 10’ X 7’-6” (see Note 1)

4 4 0

8’ X 14’ X 9’-4” (see Note 2)

8 4 1

8’ X 20’ X 9’-4” (see Note 2)

8 4 2

Notes:

1. Only half of the number of conduits specified shall be used at any given time, the rest are

intended as spare conduits. No more than one circuit allowed in the same vault.

2. If the designer is installing (1) UDS switch and foresees a need of more than (1) switch with-in 10 years, the 8’ X 20’ X 9’-4” vault should be considered over the 8’ X 14’ X 9’-4” vault.


REVISION NO. 1

DATE: 03-29-2021

DESIGN MANUAL

DM 11 PAGE 7 OF 18

4.0 EQUIPMENT APPLICATION GUIDELINES

Figure 11-1: SDS Switch Applications - Looped Feed

Notes:

1. Applicable vault is 5’ X 5’ concrete vault with 12” and 6” neck extensions (total of 18 inches

of neck extension) per CU1600-15B (Parkway Style w/ hinged cover) or CU1600-15C (Traffic Rated w/ manhole cover).

2. An SDS switch may be used to loop more than 2 padmount transformers. A looped feed

should be used if the subsystem feeds multiple customers or if the subsystem feeds Critical Infrastructure such as water wells, police stations and fire stations. The connected kVA should not exceed 200 primary Amps or approximately 4,250 kVA connected kVA.

3. An SDS may be placed within the 10’ easement in front of the transformer pad.

4. When designing, the two piece parkway hinged cover opening should be parallel to the

conduits for ease of pulling cable.

5. SGS switches are no longer utilized in new construction, and are only considered in maintenance applications. Utilize SDS for new construction applications.

REVISION NO. 1


DATE: 03-29-2021

DESIGN MANUAL

DM 11 PAGE 8 OF 18

Figure 11-2: SDS Switch Applications - Radial Feed

Notes:

1. Applicable vault is 5’ X 5’ concrete vault with 12” and 6” neck extensions (total of 18 inches of neck extension) per CU1600-15B (Parkway Style w/ hinged cover) or CU1600-15C (Traffic Rated w/ manhole cover).

2. An SDS switch may be used to radial feed 2 padmount transformers from a riser or a switch.

A radial feed may be used if the subsystem feeds single or dual customers. The connected kVA should not exceed 200 primary Amps or approximately 4,250 kVA connected kVA.

3. An SDS may be placed within the 10’ easement in front of the transformer pad.

4. When designing, the two piece parkway hinged cover opening should be parallel to the

conduits for ease of pulling cable.

5. SGS switches are no longer utilized in new construction, and are only considered in maintenance applications. Utilize SDS for new construction applications.


REVISION NO. 1

DATE: 03-29-2021

DESIGN MANUAL

DM 11 PAGE 9 OF 18

Figure 11-3: Padmount Switch Applications – PMH-9

Notes:

1. Applicable vault is 5’ X 10’-6” X 7’ vault (tub type) per CU1600-3J or 6’ X 9’-6” pad with 5’ X 8’-6” cable box per CU1600-1A and CU1600-3D.

2. A PMH-9 switch is used to feed up to (2) 200 Amp switched positions of either a

commercial/industrial subsystem or residential subsystem.

3. SDS switches may be fed from a 200 Amp switch position in a PMH-9 switch.

4. 5’ X 10’-6” X 7’ vault (tub type) is the preferred structure type over the 6’ X 9’-6” pad with 5’ X 8’-6” cable box in installing PMH-9 to PMH-13 padmount switches because of less vaults that need to be installed.

5. PMH switches are the preferred switch types over UDS due to ease of switching and

maintenance.

6. Contact Protection and System Planning Groups to determine switch positions to be automated. Automation of PMH switches shall be accomplished per CU 2100-03.

REVISION NO. 1


DATE: 03-29-2021

DESIGN MANUAL

DM 11 PAGE 10 OF 18


Notes:


2. A PMH-10 switch is used mainly for the main feeder with (4) 600 Amp switch positions. It is

mainly used to sectionalize the main feeder (more commonly at street intersections) or to tie one or more circuits together. A PMH-10 may be used if the designer anticipates that there is no need to feed a commercial/industrial subsystem or residential subsystem.

3. 5’ X 10’-6” X 7’ vault (tub type) is the preferred structure type over the 6’ X 9’-6” pad with 5’

X 8’-6” cable box in installing PMH-9 to PMH-13 padmount switches because of less vaults that need to be installed.


maintenance.



REVISION NO. 1

DATE: 03-29-2021

DESIGN MANUAL

DM 11 PAGE 11 OF 18


Notes:


2. A PMH-11 switch is used to feed up to (1) 200 Amp switched position of either a





maintenance.


REVISION NO. 1


DATE: 03-29-2021

DESIGN MANUAL

DM 11 PAGE 12 OF 18


Notes:


2. A PMH-12 switch is used to feed up to (3) 200 Amp switched positions of either a





maintenance.



REVISION NO. 1

DATE: 03-29-2021

DESIGN MANUAL

DM 11 PAGE 13 OF 18


Notes:


2. A PMH-13 or Automatic Transfer Switch (ATS) is used mainly for a customer that requires

a back-up circuit with automatic switching between the Preferred Circuit and the Back-up Circuit in case there is a problem with the preferred circuit.

3. 5’ X 10’-6” X 7’ vault (tub type) is the preferred structure type over the 6’ X 9’-6” pad with 5’

X 8’-6” cable box in installing PMH-9 to PMH-13 padmount switches because of less vaults that need to be installed.


maintenance.


REVISION NO. 1


DATE: 03-29-2021

DESIGN MANUAL

DM 11 PAGE 14 OF 18

Figure 11-8: Padmount Switch Applications – PMV-9

Notes:

1. Applicable vault 8’ X 10’ X 7’ vault per CU1600-3J.

2. A PMV-9 switch is used to feed up to (2) 200 Amp switched positions of either a commercial/industrial subsystem or residential subsystem.

3. SDS switches may be fed from a 200 Amp switch position in a PMV-9 switch.

4. PMV switches are no longer utilized in new construction, and are only considered in

maintenance applications. UDS is the preferred switch for new construction applications.

5. Contact Protection and System Planning Groups to determine switch positions to be automated. Automation of PMV switches shall be accomplished per CU 2100-3.


REVISION NO. 1

DATE: 03-29-2021

DESIGN MANUAL

DM 11 PAGE 15 OF 18

Figure 11-9: Padmount Switch Applications – PMV-10

Notes:

1. Applicable vault 8’ X 10’ X 7’ vault per CU1600-3J.

2. A PMV-10 switch is used mainly for the main feeder with (4) 600 Amp switch positions. It is mainly used to sectionalize the main feeder (more commonly at street intersections) or to tie one or more circuits together. A PMV-10 may be used if the designer anticipates that there is no need to feed a commercial/industrial subsystem or residential subsystem.

3. PMV switches are no longer utilized in new construction, and are only considered in

maintenance applications. UDS is the preferred switch for new construction applications.

4. Contact Protection and System Planning Groups to determine switch positions to be automated. Automation of PMV switches shall be accomplished per CU 2100-03.

REVISION NO. 1


DATE: 03-29-2021

DESIGN MANUAL

DM 11 PAGE 16 OF 18

Figure 11-10: Subsurface Switch Applications – UDS-9 & UDS-10

Notes:

1. Applicable vault 8’ X 14’ X 9’-4” vault per CU1600-3F or 8’ X 20’ X 9’-4” per CU1600-3H.

2. A UDS-9 switch is used to feed up to (2) 200 Amp switched positions of either a


3. A UDS-10 switch is used mainly for the main feeder with (4) 600 Amp switch positions. It is mainly used to sectionalize the main feeder (more commonly at street intersections) or to tie one or more circuits together.

4. SDS switches may be fed from a 200 Amp switch position in a UDS-9 switch.

5. UDS switches are the least preferred switch over the PMC due to switching and

maintenance.


REVISION NO. 1

DATE: 03-29-2021

DESIGN MANUAL

DM 11 PAGE 17 OF 18

6. Contact Protection and System Planning Groups to determine switch positions to be automated. Automation of UDS switches shall be accomplished per CU 2100.

Figure 11-11: Subsurface Switch Applications – UDS-11 & UDS-12

Notes:

1. Applicable vault 8’ X 14’ X 9’-4” vault per CU1600-3F or 8’ X 20’ X 9’-4” per CU1600-3H.

2. A UDS-11 switch is used mainly for the main feeder with (3) 600 Amp switch positions and can feed up to (1) 200 Amp switched position of either a commercial/industrial or residential subsystem. It is mainly used to sectionalize the main feeder (more commonly at street intersections) or to tie one or more circuits together. A UDS-10 may be used if the designer anticipates that there is no need to feed a commercial/industrial subsystem or residential subsystem.

3. A UDS-12 switch is used to feed up to (3) 200 Amp switched positions of either

commercial/industrial or residential subsystems and (1) 600 Amp main switched position. It is mainly used to pick up load.

4. UDS switches are the least preferred switch over the PMC due to switching and

maintenance.

REVISION NO. 1


DATE: 03-29-2021

DESIGN MANUAL

DM 11 PAGE 18 OF 18

5. Contact Protection and System Planning Groups to determine switch positions to be automated. Automation of UDS switches shall be accomplished per CU 2100.

Section DM 12

FORMS

FORMS

REVISION NO. 1

DATE: 03-29-2021

DESIGN MANUAL

DM 12 PAGE 1 OF 11

SECTION DM 12: FORMS

TABLE OF CONTENTS No. TITLE PAGE 12-1 Form 12-1 DPA Request 2 12-2 Form 12-2 Request for Fuse Calculation 3 12-3 Form 12-3 General Services & Master Agreement Authorization 4 12-4 Form 12-4 Master Agreement Advertise Letter 6 12-5 Form 12-5 Master Agreement Proposal 7 12-6 Form 12-6 Master Agreement Award Letter 9 12-7 Form 12-7 Master Agreement Completion Letter 10 12-8 Form 12-8 Master Agreement Conflict of Interest 11

REVISION NO. 1

FORMS

DATE: 03-29-2021

DESIGN MANUAL

DM 12 PAGE 2 OF 11

Form 12-1: DPA Request Distribution Power Analysis (DPA) Request Form is used when System Planning Study is required such as new commercial risers, new circuits, or significant load that can impact the overall distribution system.

FORMS

REVISION NO. 1

DATE: 03-29-2021

DESIGN MANUAL

DM 12 PAGE 3 OF 11

Form 12-2: Request for Fuse Calculation Request for Fuse Calculation Form is used if a subsystem is required to be fused at the feeder interface. A DPA analysis is also required to determine the available primary fault current.

REVISION NO. 1

FORMS

DATE: 03-29-2021

DESIGN MANUAL

DM 12 PAGE 4 OF 11

Form 12-3: General Services & Master Agreement Authorization General Services & Master Agreement Authorization Form is required for preliminary approval of a project. It is used to ensure that there is sufficient budget to complete the project under the Capital Improvement Program’s unit.

FORMS

REVISION NO. 1

DATE: 03-29-2021

DESIGN MANUAL

DM 12 PAGE 5 OF 11

REVISION NO. 1

FORMS

DATE: 03-29-2021

DESIGN MANUAL

DM 12 PAGE 6 OF 11

Form 12-4: Master Agreement Advertising Letter Master Agreement Advertising Letter is used as a invitation to request bids from prequalified High-Voltage Contractors for Master Agreement Construction Projects. The latest list of prequalified contractors and consultants can be found on the Designer Homepage.

FORMS

REVISION NO. 1

DATE: 03-29-2021

DESIGN MANUAL

DM 12 PAGE 7 OF 11

Form 12-5: Master Agreement Proposal Master Agreement Proposal Form is used by the pre-qualified contractor submitting their bid for a Master Agreement Project.

REVISION NO. 1

FORMS

DATE: 03-29-2021

DESIGN MANUAL

DM 12 PAGE 8 OF 11

FORMS

REVISION NO. 1

DATE: 03-29-2021

DESIGN MANUAL

DM 12 PAGE 9 OF 11

Form 12-6: Master Agreement Award Letter Master Agreement Award Letter is used to formally award the construction contract to the lowest responsible prequalified contractor.

REVISION NO. 1

FORMS

DATE: 03-29-2021

DESIGN MANUAL

DM 12 PAGE 10 OF 11

Form 12-8: Master Agreement Completion Letter Master Agreement Completion Letter is used to formally provide notification when the project has been completed.

FORMS

REVISION NO. 1

DATE: 03-29-2021

DESIGN MANUAL

DM 12 PAGE 11 OF 11

Form 12-9: Master Agreement Conflict of Interest Master Agreement Conflict of Interest Form is required to be executed by the prequalified contractor prior to awarding the project contract.

Section DM 13

GLOSSARY

GLOSSARY

REVISION NO. 0

DATE: 03-07-2013

DESIGN MANUAL

DM 13 PAGE 1 OF 9

SECTION DM 13: GLOSSARY A Access Right The right of an owner to have ingress and egress to and from his property. ACSR Aluminum Cable Steel Reinforced. Added Facilities Added Facilities may include, but are not limited to, all types of equipment

normally installed by the City in the development of its electrical transmission and distribution systems and facilities or equipment related to the City’s provision of service to a customer or a customer’s receipt or utilization of City’s electrical energy. Added facilities also include the differential costs for equipment for electrical transmission and distribution systems designed by the City which, in the City’s sole opinion, is in excess of equipment required for City’s standard serving system.

Alternating Current (AC) A current with a magnitude that oscillates above and below zero (reverses

direction) in a periodic manner. Ampere (A) The standard unit for measuring electric current. One ampere represents a charge

flow of one coulomb per second. AWG American Wire Gage. B Balance Refers to the degree with which each circuit phase carries equal amounts of

current. Balanced Current A circuit in which there are substantially equal current, either AC or DC, in all main

wires. Balanced Voltage A circuit in which there is substantially equal voltages, either AC or DC, between

main wires and between each main wire and neutral, if one exists. Bundle A circuit phase consisting of more than one conductor. Each conductor of the

phase is referred to as a subconductor. BURD Buried Underground Residential Distribution. C Charge The quantity of electrons or ions that is stored on a conductor, analogous to a

quantity of water stored in a vessel. To store electrical charges in a device.

REVISION NO. 0

GLOSSARY

DATE: 03-07-2013

DESIGN MANUAL

DM 13 PAGE 2 OF 9

CIC Conductor in Conduit. Flexible underground conduit containing current carrying

conductor. Circuit A circuit refers to any set of primary cables passing through the structure, and is

the same as two primary cable runs. A circuit may be pulled straight through or connected with permanent straight splices, T-splices, or a switch.

Circuit Ties Circuit ties are those points on the feeder where an adjacent feeder can be

paralleled through a switch position. These ties enable load transfers during routine and emergency operating conditions.

Climbing Space The space reserved along the surface of a climbable pole or structure to permit

linemen ready access to equipment and conductors on the pole or structure. Climbing space shall be maintained from the ground level.

Commercial/Industrial (C/I) Commercial/Industrial. Refers to a customer classification. Concentric A series of small wires at ground potential designed to carry neutral current,

helically wound over the surface of underground insulated phase conductors. Condemnation The exercise of the power of eminent domain; that is, taking of private property for

public use. Conductor A substance capable of passing electric current. Good conductors are generally

made of metal, although other substances, such as the earth or the human body, can be relatively good conductors.

Contiguous In actual or close contact; touching; adjacent; near. Coulomb (C) The standard unit for measuring electric charge. One coulomb contains 6.24 x

1018 elemental charges. Current The flow of electric charge. Measured in “rms” amps for magnetic field

calculations. Customer Demand The peak demand that a customer is expected to reach during a 12-month period. D Demand Factor The ratio of peak demand to connected load, expressed as a percentage. Distribution Power delivery system below 35,000 Volts (35 kV).

GLOSSARY

REVISION NO. 0

DATE: 03-07-2013

DESIGN MANUAL

DM 13 PAGE 3 OF 9

Duty (Also: Short-Circuit Duty) The amount of electric energy at a particular location under a short-circuit condition.

E Easement A right or interest in the land of another which entitles the easement holder thereof

to some use, privilege, or benefit (such as to place pole lines, roads, thereon or travel over) out of or over said land.

Electric Field Field resulting from presence of voltage. Measured in volts per meter (V/m).

Electric fields can be shielded by conducting material. Electric fields are not the primary focus of the design guidelines.

Electrolier An ornamental amp post with the necessary internal channels and openings for

wiring and external attachments for bracket and luminaire. Electromagnetic Field A condition of space containing both electric and magnetic fields. Eminent Domain The right or power of the government or take private property for public use on

making just compensation. Encroachment Trespass; the building of a structure or improvements, partly or wholly on the

property of another. Energy The capacity for doing work or producing heat. Enterprise A separate business or other individual activity carried on by a customer. The term

does not apply to associations or combinations of customers. EUSERC Electric Utility Service Equipment Requirements Committee – The purpose of the

organization is to promote uniform electric service requirements among the member utilities, publish existing utility service requirements for electric service equipment and provide direction for development of future metering technology.

F Feeder The arterial portion of circuitry which forms the 12 kV network interconnecting

circuits and substations. Ferroresonance An electrical condition that sometimes occurs when the capacitive reactance of the

underground cables is approximately equal to the inductive reactance of the transformer. Due to switching or a fuse operation, these reactances can become connected in series. Since they tend to cancel each other, large amounts of current will flow with extremely high voltages developing across the cable and transformer.

REVISION NO. 0

GLOSSARY

DATE: 03-07-2013

DESIGN MANUAL

DM 13 PAGE 4 OF 9

FI Fault Indicator. This is a device utilized for the analysis of circuit interruptions on overhead and underground distribution circuits.

Fiberglass Reinforced Plastic Used in the construction of handholes. Franchise Permission to install electrical facilities along public streets or thoroughfares. Frequency The number of cycles per second (Hertz) of an alternating current or voltage. The

frequency of power equipment in the United Stated is 60 Hertz. In many other countries, a frequency of 50 Hertz is used.

G G.O. 128 CPUC General Order 128, is the State of California Rules for Underground Electric

Line Construction. G.O. 95 CPUC General Order 95, is the State of California Rules for Overhead Electric

Line Construction. Gauss (G) A common unit for measuring magnetic fields. Getaway That portion of a feeder beginning at the substation and continuing to the first

overhead structure or the first underground switch position. No load should be connected to the getaway section of feeders.

Guy A tension member (solid wire or stranded wires) used to counter an otherwise

unbalanced force on a pole, crossarm, or other overhead line structure. H Heavy Loading The strength requirements specified in G.O.95 for poles and conductors as

affected by wind, ice, and temperature, in areas where the elevation exceeds 3,000 feet above sea level.

Hertz (Hz) Measurement of frequency of an alternating electric source in cycles per second. I Impedance The quality of a substance or device which resist the flow of current. Even good

conductors have a certain amount of impedance. For the non-specialist, impedance and resistance may be thought to express a similar phenomenon, but there are technical differences between these two terms.

Insulation A substance that conducts current poorly.

GLOSSARY

REVISION NO. 0

DATE: 03-07-2013

DESIGN MANUAL

DM 13 PAGE 5 OF 9

J K Kcmil 1,000 circular mills, size of conductors, cross-sectional area. Kilo (k) Prefix indicating one thousand. KVA KiloVolt Amps, a measure of electrical power. L Light Loading The strength requirements specified in G.O.95 for poles and conductors as

affected by wind, ice, and temperature, in areas where the elevation above sea level is 3,000 feet or less.

Load Break Elbow A pre-molded 200 Amp rated primary cable termination that can be operated

energized. Load Factor The ratio of the average monthly demand divided by the monthly peak demand

expressed as a percentage. Luminaire An illumination device containing a light source. M Magnetic Field A region of influence around a moving charge or current. The intensity is

measured by the magnetic flux density B, in milliGauss (mG). Magnetic fields are not readily shielded by the ground, buildings, and so on.

Master Plan The master plan identifies (within the City of Anaheim) the required plans for

circuitry and substations, based on ultimate or forecast land use. Mega (M) Prefix meaning one million. Micro (μ) Prefix indicating one one-millionth. Milli (m) Prefix indicating one one-thousandth. Minimum Trip The minimum current (amperes) that will cause the feeder circuit breaker at the

substation to open. Multi Family Dwellings Dwelling, such as apartment buildings with more than two walls (floors and ceilings

included) in common with other dwelling units.

REVISION NO. 0

GLOSSARY

DATE: 03-07-2013

DESIGN MANUAL

DM 13 PAGE 6 OF 9

Multiplex A section of conductors consisting of two (duplex), three (triplex), or four (quadraplex) individual insulated conductors twisted around each other. These are generally used as service or secondary wiring.

N Neutral Current or conductor carrying current returning to the source. Neutrals are at

ground potential and not considered a “phase” of the circuit. Earth may be a neutral path back to the source.

Normal Operating Conditions The state of system operation when all components of the system are energized

and operating properly, and no temporary or emergency conditions exist. O&M Operation and Maintenance Policy and Procedures Manual. O Occupied Space Rooms, buildings, playgrounds, and other areas where people may spend

extended periods of time. Open Wire (open-wire) Secondary voltage conductors on separate insulators and not twisted together. Operating Convenience This means the utilization, under certain circumstances, of facilities or practices

not normally employed, which contribute to the overall efficiency of the City’s operation. It does not refer to customer convenience nor to the use of facilities or practices required to comply with applicable laws, ordinances, rules or regulations, or similar requirements of public authorities.

Overhead (OH) Overhead refers to electrical overhead conductors and equipment mounted on

poles. P Padmount Equipment (transformers, switches, etc.) which sits on the ground on concrete like

“pads” fed by underground conductors. Peak Load The maximum load expected on the circuit or subsystem being considered. Phase Electric current, voltage, or conductors carrying electricity greater than ground

potential. Each “phase” of a circuit will have unique electrical values at any point in time, compared with other “phases” of the same circuit.

Phase Conductors One of the three sets of current-carrying wires in a three-phase AC power line.

GLOSSARY

REVISION NO. 0

DATE: 03-07-2013

DESIGN MANUAL

DM 13 PAGE 7 OF 9

Phased/Phasing The physical positioning of each phase of the circuit(s) on a pole line with respect to each other

Photocontroller A small device containing a light sensitive cell and a switch to turn the lights on

when light decreases to a predetermined level, turning them off in the morning when the light increases to a certain level.

PME Padmounted Elbow Connected. Designates a dead-front (elbow connected) air

insulated switch. PMH Padmounted Housing. Designates a live front air insulated switch. Power Factor (PF) The ratio of true power (kW) divided by apparent power (kVA) expressed as a

percentage. Primary Signifies voltage or conductors carrying voltage greater than 600 volts on the

distribution system. Also refers to the “high side” voltage on a transformer. Q R Right of Way (ROW) The right of passage over another person’s land. Right of Way is an easement.

Through usage at the City of Anaheim, the term has come to mean any right (fee, license or easement) secured to permit the construction, maintenance, reconstruction or removal of one’s facilities on someone else’s property.

Rules The rules promulgated by the California Public Utility Commission (CPUC) which

are applicable to design and installation of a distribution system being considered. S Safety Factor The minimum allowable ratio of ultimate strength of materials to the maximum

working stresses as defined in G.O.95. Secondary Voltage or conductors carrying voltage less than 600 volts on the distribution

system. Also refers to the “low side” voltage on a transformer. Service Point The service point is where the utility enters the customer’s property. Service Termination The Service Termination is the location where the utility’s conductors attach to the

terminals of the customer’s service equipment or splice to the customer’s service entrance conductors, regardless of the location of meters or transformers.

REVISION NO. 0

GLOSSARY

DATE: 03-07-2013

DESIGN MANUAL

DM 13 PAGE 8 OF 9

Services Conductors carrying power to customer meter panel, generally at secondary voltages less than 600 Volts.

SF6 SF6 (sulfur hexafluoride) is an excellent gaseous dielectric for high voltage power

switches. It is a gas that is nontoxic, nonflammable, colorless, and odorless. The gas will cause suffocation if inhaled directly from a cylinder or if concentrated in an enclosed area without proper ventilation.

Shielding A substance or device that possibly reduces electric or magnetic fields. Short Circuit An abnormal connection (including an arc), of relatively low impedance, between

two points of different potentials. Single Family Residences Dwelling units (such as single family homes, condominiums, and townhomes) with

no more than two walls (floors and ceilings included) in common with other dwelling units.

Subsystems Three-phase and/or single-phase laterals serving C/I developments and/or

residential developments. Subsystems will generally be 200 Amp systems utilizing #2, 1/0 or 4/0 cable, and 200-amp-rated equipment.

Subtransmission Power delivery system at voltages between 35,000 and 75,000 volts (35 kV – 75

kV). Swing The movement of conductor, or amount of movement, due to wind blowing on the

conductor. T Transmission Power delivery system above 75,000 Volts (75 kV). Transmission System An interconnected group of electric transmission lines and associated equipment

which transfer electric energy, in bulk, between points of supply and points of delivery.

Transposed Line A line in which the phase of conductors of the circuit have interchanged

conductors on the structure between successive lengths of line so as to minimize electrical unbalances.

U Unbalance A condition in a three phase system where unequal amounts of current carried on

each phase of the circuit. Uncorrected Power Factor The power factor of the load on a circuit if there were no capacitors on line.

GLOSSARY

REVISION NO. 0

DATE: 03-07-2013

DESIGN MANUAL

DM 13 PAGE 9 OF 9

Underbuild The lower voltage circuit(s) constructed beneath a higher voltage circuit on the same pole line.

Underground (UG) Underground refers to electrical underground conductors and surface and below

ground equipment. Usable Pole Strength Indicates the maximum bending moment that may be applied to a pole (due to

wind loading and conductor strain) for a given wind area without exceeding the safety factor for the specified grade of construction. Grade “A” construction requires a safety factor of 4:1 and Grade “B” requires a safety factor of 3:1.

V Var/Watt Ratio The ratio of vars to watts represents the uncorrected power factor of the customer

load on a circuit/substation. VFI Vacuum Fault Interrupter. Designates apparatus containing switches and/or

vacuum interrupters used for protecting and switching large transformers. The switches and vacuum bottles can be oil insulated or SF6 insulated.

Volt (V) The standard unit for measuring voltage. Voltage The electrical force which propels current in a conductor. Volts per Meter (V/m) A standard unit for measuring the strength of an electric field. W Working Space The space extending laterally from the climbing space, reserved for working

below, above, and between conductor levels. X Y Z

electrical engineering design manual

Documents