ELECTRICAL SYSTEMS

1.1 DEFINITION OF ELECTRICITY

• a form of energy generated by friction, induction or chemical change, having magnetic, chemical and radiant effect. • the motion of free electrons through a solid conductor.

1.2 SOURCES OF ELECTRICITY

STORAGE BATTERIES

GENERATORS

1. GENERAL

STORAGE BATTERIES

• are used to supply emergency lighting circuits for hallways, stairways, exits and to energize police and fire alarm systems and certain types of signal systems.

GENERATORS

for generating electric current

• Alternating Current Generators or Alternators – The bulk of electrical energy utilized today is in the form of alternating current, including energy for power and lighting.• Direct Current Generators – These furnish electrical energy for elevators, escalators, intercommunicating telephone systems, control of signal systems, and clock systems.

1.3 OTHER DYNAMO ELECTRIC MACHINES

MOTORS – for converting electrical energy to mechanical energy.TRANSFORMERS – for converting one voltage to another, from lower to higher or from higher to lowerROTARY CONVERTERS – for changing alternating current to direct current and vice versa.

1.4 TYPES OF CURRENT

ALTERNATING CURRENT – a current which is periodically varying in time rate and in direction. It rises from zero to maximum, falls to zero, reverses its direction and again returns to zero.

DIRECT CURRENT – a current which flows at a constant time rate and in the same direction.

UNIT OF QUANTITY

1.5 UNITS OF ELECTRICITY

COULOMB – a coulomb of electricity comprises approximately 6.25 x 10 18 electrons.AMPERE – An ampere of current represents a rate of flow of one coulomb or 6.25 x 10 18 electrons/second through a given cross section.

UNIT OF ELECTRIC POTENTIAL

VOLT – is the electromotive force or potential difference between two points in an electric field which will move a charge of one coulomb between these points.

UNIT OF RESISTANCE

OHM – The resistance which will allow one ampere of current to flow when one volt is impressed upon it.

UNIT OF ELECTRIC POWER

WATT – the unit of electric power or the rate of doing electrical work.

UNIT OF ENERGY

WATT-HOURS – the unit of energy or the capacity for doing work.

1.6 OHM’S LAW

I (amp) = V (Volts) / R (Ohms)

The current, I, that will flow in a d-c circuit is directly proportional to the voltage ,V, and inversely proportional to the resistance , R, of the circuit.

– is the effective utilization of available energy by reducing peak loads and lowering demand charge. The control devices and systems are referred to as load shedding control, peak demand control, peak load regulation, and power use control.LOAD SCHEDULING AND DUTY-CYCLE CONTROL – the installation’s electric loads are analyzed and scheduled to restrict demand by shifting large loads to off-peak hours and controlled to avoid coincident operation.

DEMAND METERING ALARM – in conjunction with a duty cycle controller, demand is continuously metered and an alarm is set on when a predetermined demand level is exceeded.

1.7 ELECTRIC LOAD CONTROL

AUTOMATIC INSTANTANEOUS DEMAND CONTROL – also called “rate control”, it is an automated version of the demand metering alarm system, where it automatically disconnects or reconnects loads as required.

IDEALCURVE CONTROL – This controller operates by comparing the actual rate of energy usage to the ideal rate, and controls KW demand by controlling the total energy used within a metering interval.

FORECASTING SYSTEMS – are computerized systems which continuously forecast the amount of energy remaining in the demand interval, then examine the status and priority of each of the connected loads and decide on the proper course of action.

WATTMETER

VOLTAGE LEADS

LOAD

WM

CURRENT LEADS

POWER SOURCE

1.8 MEASURING ELECTRIC CONSUMPTION

KWH METERS – To measure energy, the factor of time is introduced, such that; energy = power x time. A-C electric meters are basically small motors, whose speed is proportional to the power being used. The number of rotations is counted on the dials which are calibrated directly in kilowatt-hours.

2. BUILDING ELECTRICAL SYSTEMS

2.1 BRANCH CIRCUITS An electrical circuit may be defined as a complete conducting path carrying current from a source of electricity to and through some electrical device or load and back to the source. The two wire circuit, which is the most elementary of all wiring systems, consists of a live wire carrying the current to the various power consuming devices in the circuit and a neutral or grounded wire which is the return wire carrying the circuit back to the source of supply.

SERIES CIRCUIT

PARALLEL CIRCUIT

SERIES CIRCUIT – is one in which the components are connected in tandem. All separate loads of the circuit carry the same equal current and the total resistance, R, is the sum of the resistances around the circuit.

PARALLEL CIRCUIT (or Multiple Circuit) – is one in which the components or loads are so arranged that the current divides between them. Each outlet has a live wire connected to the current carrying wire of the circuit and also a neutral wire or grounded wire connected to the return wire of the circuit. With this system, the total current flowing through the circuit is the sum of the current flowing through each outlet.

R = R1 + R2 + R3 + R4 + R5

10 ampR 1 R 2

10 amp

ELECSOURCE

CIRCUIT IN SERIES

R 5 R 410 amp10 amp

R 3

ELECTRICAL SOURCE

CIRCUIT IN PARALLEL

3 amp

1 amp1 amp1 amp+

R 1 R 2 R 3

1 R = 1/R1 + 1/R2 + 1/R3

CLASSIFICATIONS OF BRANCH CIRCUITS

General Purpose Branch Circuit - supplies outlets for lighting and appliances, including convenience receptacles.

Appliance Branch Circuit - supplies outlets intended for feeding appliances. Fixed lighting is not supplied.

Individual Branch Circuit - is designed to supply a single specific item, such as a motor load or a unit air-conditioner.

SIZE REQUIRED FOR ITEM FED

15, 20, 30, or 50A A A

LTG AGENERALLY 15, 20A

SINGLE ITEM

Branch CircuitThe portion of an electrical system extending from the final overcurrent device protecting a circuit to the outlets served by the circuit

Distribution PanelA panel for distributing power to other panels or to motors and other heavy power-consuming loads. Controls, distributes and protects a number of similar branch circuits in an electrical system

Low-VoltageOf or pertaining to a circuit in which alternating current below 50 volts is supplied by a step-down transformer form the normal line voltage used in residential systems to control doorbells, intercoms, heating and cooling systems and remote lighting fixtures. Low-voltage circuits do not require a protective raceway

General Purpose CircuitA branch circuit that supplies current in a number of outlets for lighting and appliances

Appliance CircuitA branch circuit that supplies current in one or more outlets specifically intended for appliances

Individual CircuitA branch circuit that supplies current only to a single piece of electrical equipment

GENERAL CIRCUITING GUIDELINES

1. General: Branch circuits shall be sufficient to supply a load of 30 watts per square meter (3 watts per square foot) in buildings excluding porches, garages and basements.

2. In all but the smallest installations, connect lighting, convenience receptacles, and appliances in separate circuits. The Code requires a minimum of 2 - 20 amperes appliance branch circuit to feed all small appliance outlets in the kitchen, pantry, dining and family room.

DIN

E

KIT

Ref

C2

Range

C1

C4

C3

C3

C320 amp

20

am

p

3. Convenience receptacles in an area shall be wired to at least two different circuits so that in case of failure in any one of the circuits, the entire area will not be deprived of power.

4. General purpose branch circuits shall be rated at 20 amperes wired with No. 12 AWG minimum. Switch legs may be No. 14 AWG if the lighting load permits.

5. Limit the circuit load for lighting and small appliances on 15 amp and 20 amp circuit loads and on 15 and 20 amp overcurrent devices respectively.

2.2 SINGLE PHASE ELECTRICAL SYSTEMS

Two-Wire Single Phase DC or AC

Three-Wire Single Phase DC (EDISON SYSTEM)

Three-Wire Single Phase AC

For homes and small commercial buildings

SWITCH FUSE

220 V

110 V

110 V

A single phase electrical system can either be 2-wire or 3-wire and composes two hot legs and a neutral wire.

2.2 THREE PHASE ELECTRICAL SYSTEMS

Three-Wire Three Phase AC

Four-Wire Three-Phase AC

For industries and large commercial buildings

A-B 220V

B-C 220V

A-C 220V

A B C

A

B

C

220V

N B CA

220V

220V

110V

110V

110V

MOTOR

The Three Phase AC electricity is a Triple Circuit. The lighting and outlet loads are connected between any phase leg and a neutral line. While machineries and other bigger loads are connected to the phase leg only.

2.3 COMPONENTS OF THE BUILDING ELECTRICAL SYSTEM

SubstationAn auxiliary power station where electrical current is converted or where voltage is stepped up or down

ServiceThe supplying of utilities required or demanded by the public

Line DropThe decrease in voltage between two points on a power line, usually caused by resistance or leakage along the line

Service Entrance ConductorThe portion of a service conductor extending from a service drop or service lateral to the service equipment of a building

Watt-Hour MeterA meter for measuring and recording the quantity of electric power consumed with respect to time

Transformer VaultA fire-rated room housing a transformer and auxiliary equipment for a large building

Switchgear RoomContains the service equipment for a large building

Service EquipmentEquipment necessary for controlling, metering and protecting the electric power supply to a builidng

Standby GeneratorFor providing emergency power during a power outage.

Uninterruptible Power SupplyAn emergency system designed to provide pwer automatically and instantaneously

SwitchboardOne or a group of panels on which are mounted switches, overcurrent devices, metering instruments and buses

Unit SubstationA freestanding enclosure housing a disconnect switch, a step-down transformer and switchgear

FeederAny of the conductors extending from the service equipment to various distribution points in a building

Service DropThe overhead portion of service conductors extending from the nearest utility pole to a building

Service LateralThe underground portion of service conductors extending from a main power line or transformer to a building

Lightning RodAny of several conducting rods installed at the top of a structure and grounded to divert lightning away from the structure. Also called air terminal

Lightning ArresterA device for protecting electric equipment from damage by lightning or other high-voltage currents, using spark gaps to carry the current to the ground without passing through the device

Spark GapA space between two terminals or electrodes across which a discharge of electricity may pass at a prescribed voltage

Servcie DropThe overhead portion of service conductors extending from the nearest utility pole to a building

Servcie LateralThe underground portion of service conductors extending from a main power line or transformer to a building

Service Conductors extend from a main power line or transformer to the service equipment of a building

Servcie Entrance ConductorThe portion of a service conductor extending from a service drop or service lateral to the service equipment of a building

Watt-Hour MeterMeasures and records the quantity of electric power consumed with respect to time. Supplied by the public utility, it is always placed ahead of the main disconnect switch so that it cannot be disconnected

For multiple-occupancy buildings, banks of meters are installed so that each unit can be metered independently

Grounding Rod or ElectrodeIs firmly embedded in the earth to establish a ground connection

To panelboards

Direct burial cable may be used for residential service connections

A transformer is used by medium-sized and large buildings to step down from a high supply voltage to the service voltage. To reduce costs, maintenance and noise and heat problems, a transformer may be placed on an outdoor pad. If located within a building, oil-filled transformers require a well-ventilated, fire-rated vault with two exits and located on an exterior wall adjacent to the switchgear room. Dry-type transformers used in small- and medium-sized buildings may be replaced together with a disconnect switch and switchgear in a unit substation

The service switch is the main disconnect for the entire electrical system of a building, except for any emergency power systems.

The service equipment includes a main disconnect switch and secondary switches, fuses and circuit breakers for controlling and protecting the electric power supply to a building. It is located in a switchgear room near the entrance of the service conductors

The main switchboard is a panel on which are mounted switches, overcurrent devices, metering instruments and busbars for controlling, distributing and protecting a number of electric circuits

SERVICE ENTRANCE– the point of delivery of electricity to a building by a public utility company.

MAIN SWITCHBOARD – The service entrance conductors in the form of bus bars terminates in the main switchboard and connects to the distribution panel boards by means of feeder circuits protected by circuit breakers. The main switchboard serves for the control, protection and metering of the main feeders.

FEEDER CIRCUITS – A feeder circuit is a set of conductors which extends from the main switchboard to a distributing center (panel board) with no other circuits connected to it between the source and the distributing center.

SUB-FEEDER CIRCUITS – are line extensions of a feeder, fed through a panel board or cut-out, or from one distributing center to another and having no other circuit connected to it between the two distributing centers. A sub-feeder serves to distribute power from the main feeders to smaller local panel boards, called sub-panel boards.

PANEL BOARDS AND SUB-PANEL BOARDS (also called CUT-OUTS) – These serve to control and protect the sub feeders and branch circuits.

UTILIZATION EQUIPMENT – These are the lighting, power and motor loads and wiring devices which are directly handled and utilized by users.

BRANCH CIRCUITS – These are small capacity conductors which deliver energy to lamps, motors and other loads within the circuit.

Service SwitchThe main disconnect for the entire electrical system of a building except for any emergency power systems

PanelA board on which are mounted the switches, fuses and circuit breakers for controlling and protecting a number of similar branch circuits installed in a cabinet and accessible from the front only. Also called a panelboard.

BusA heavy conductor, usually in the form of a solid copper bar, used for collecting, carrying and distributing large electric currents. Also called a busbar

Grounded ConductorAny conductor of an electrical system intentionally connected to a ground connection

Grounding ElectrodeA conductor, as a metal ground rod, ground plate or cold-water pipe, firmly embedded in the earth to establish a gorund connection

FuseA device containing a strip or wire of fusible metal that melts under the heat produced by excess current thereby interrupting the circuit

Circuit BreakerA switch that automatically interrupts an electric circuit to prevent excess current from damaging apparatus in the circuit or from causing a fire. A circuit breaker may be reclosed and reused without replacement of any components. Also called a breaker.

Ground WireA conductor connecting electric equipment or a circuit to a ground connection. Also called a grounding conductor

2.4 ILLUSTRATING THE COMPONENTS OF THE BUILDING ELECTRICAL SYSTEM

BLOCK DIAGRAMA horizontal single line diagram of the building’s electrical system from the incoming service to the utilization items at the end of the system where the major electrical components are shown as blocks or rectangles.

SINGLE LINE DIAGRAMWhen electrical symbols are used in lieu of the blocks, it is called a “one line” or a “single line diagram”.

TRANSFORMERVAULT

HIGH-VOLTAGEPRIMARY FEEDERS2,400, 4,160, 7,200OR 13,200 VOLTS

SECONDARY SERVICECONDUCTORS

MAIN FEEDERS

SWITCHESTRANSFORMERFUSES

120/208 OR120/240 OR227/480 VOLTS

MAINSWITCHBOARD

LARGEMOTOR

DISTRIBUTIONPANELS

MOTORPANELS

LIGHTING/APPLIANCEPANELS

BRANCHCIRCUIT

RECEPTACLESLIGHTING

SMALLMOTORS &CONTROL

RISER DIAGRAMIs a vertical line diagram of the major electrical components of the buildings electrical system presented showing the spatial relations between components.

ELEVATORSPPMR

MACHINEROOM

5A

LP

4A

3A

2A

1A LP

LOBBY

1B

2B

3B

4B

5B

LEFTRISER

5C

4C

3C

2C

1C

ROOF

CENTRAL RISER SHAFT

RIGHT RISER

M.C.C.

MACHINE ROOM

FA

LPSE

FIRE ALARMPANELSTAIR AND EXITPANEL

M METERING

SPARE

2.5 EMERGENCY ELECTRIC SUPPLY SYSTEM

Emergency Systems – provide electric power and illumination essentially for life safety and protection of property during an emergency, such as, electricity for exit lighting, elevators, fire alarm systems, fire pumps and the like.

Standby Systems – provide power to selected loads not directly involved with life safety, such as, water and sewage treatment plants and industrial machines for manufacturing processes.

EMERGENCY POWER EQUIPMENT

Battery Equipment – Central storage batteries are mounted in individual racks and always provided with automatic charging equipment.

Engine-Generator Sets – are machines intended to produce electricity and composed of three components: the machine and its housing (if any), fuel storage tank and the exhaust facilities.

EMERGENCY WIRING SYSTEMS USING THE BATTERY

Small emergency appliance connected direct to a storage battery

Groups of emergency loads connected to central storage battery through automatic device

Emergency equipment loads are entirely separate from normal loads and are generally de-energized. The contactor is activated when it senses power loss.

EMERGENCY WIRING SYSTEMS USING THE GENERATOR

Emergency system handled by a single transfer switch which automatically turns on when it senses power loss at its downstream location.

Emergency system handled by multiple switches

Emergency service totally separated from normal through its own emergency service entrance, coming from different transformers or feeders.

Same as above, but both service entrances supply normal loads and each act as standby for each other.

– are materials which allow the free flow of electrons through them.

Wires – are single insulated conductors No. 8 AWG (American Wire Gauge or smaller; for the English System, it is the B & S Gauge or Browne and Sharpe Gauge. The smallest size of wire permitted is No. 14.Cables – are single insulated conductors No. 6 AWG or larger; or they may be several conductors of any size assembled into a single unit.Bus Bars – large conductors which are not circular in cross section and usually found only to supply the main switch boards.

3. ELECTRICAL MATERIALS AND EQUIPMENT

3.1 CONDUCTORS

CONDUCTOR SIZES – AWG/MCM STANDARD

All conductor sizes from No. 16 to No. 0000 (also designated 4/0) are expressed in AWG. Beyond AWG No. 4/0, a different designation, MCM (or thousand circular mil) is used. In this designation, the smallest MCM size is 250 MCM or ½” and the biggest is 500 MCM. A circular MIL is an artificial area measurement, representing the square of the cable diameter (diam2) when the diameter is expressed in mils (thousands of an inch). Thus a solid conductor ½ inch in diameter is 500 mils in diameter, or 250,000 circular mils in area, (500)2 or 250 MCM; thus;CM/1000 = diam2 = (500)2/1000 = 250,000/1000 = 250 MCMIn the metric system, conductor sizes are given simply as the diameter in millimeters (mm).

CONDUCTOR AMPACITY

Conductor current carrying capacity or ampacity is the maximum operating temperature that its insulation can stand continuously. Heat is generated as a result of the current flowing and the conductor resistance. When conductors are placed in an enclosed conduit, the heat generated is not as easily dissipated as it would be if the conductor were free in the air. Thus, the current rating of a conductor in free air is much higher than that for the same were it in a conduit.

TYPES OF CABLESArmored Cable (Type AC) – a fabricated assembly of insulated conductors enclosed in flexible metal sheath.Metal Clad Cable (Type MC) – a factory assembled cable of one or more conductors each individually insulated and enclosed in a metallic sheath of interlocking tape of a smooth or corrugated tube.Mineral Insulated Cable (Type MI) – a factory assembled conductor/s insulated with a highly compressed refractory mineral insulation enclosed in a liquid and gas tight continuous copper sheath. Non-Metallic Sheathed Cable (Type NM or NMC) – also known by the trade name ROMEX, is a factory assembly of two or more insulated conductors having a moisture resistant, flame retardant, and non-metallic material outer sheath.

Shielded Non-Metallic Sheathed Cable (Type SNM) – a factory assembly of two or more insulated conductors in an extruded core of moisture resistant and flame retardant material covered within an overlapping spiral metal tape.Underground Feeder and Branch

Circuit Cable (Type UF) – a moisture resistant cable used for underground connections including direct burial in the ground as feeder or branch circuit.Service Entrance Cable (Type SE or USE) – a single or multi-conductor assembly provided with or without an overall covering primarily used for service wire.Power and Control Tray Cable (Type TC) – a factory assembled two or more insulated conductors with or without associated bare or covered grounding under a metallic sheath and is used for installation in cable trays, raceways, or where supported by wire.

Flat Cable Assemblies (Type FC) – an assembly of parallel conductors formed integrally with an insulating material web designed specially for field installation in square structural channels.

Flat Conductor Cable (Type FCC) – consists of three or more flat copper conductors placed edge to edge separated and enclosed within a insulating assembly. This type of cable is used for appliance or individual branch circuits installed inside floor surfaces.

Medium Voltage Cable (MV) – a single or multi-conductor solid dielectric insulated cable rated at 2,000 to 35,000 volts. Trade name is Medium Voltage Solid Dielectric.

3.2 INSULATORS

INSULATORS are materials which prevent the flow of electrons through them.

General Wiring

Trade name Type Letter

Maximum Operating Temperature

ApplicationProvisions

Moisture-& heat-resistant rubber

RHW 75O C167O F

Dry and wetLocations

Thermoplastic T 60O C140O F

Dry locations

Moisture-resistant thermoplastic

TW 60O C140O F

Dry and wetLocations

Heat-resistant thermoplastic

THHN 90O C194O F

Dry locations

Moisture-& heat-resistant thermoplastic

THW 75O C167O F

Dry and wetLocations

Moisture-& heat-resistant thermoplastic

THWN 75O C167O F

Dry and wetLocations

Moisture-& heat resistant cross-linked thermosetting polyethelene

XHHW 90O C194O F75O C167O C

Dry locationsWet locations

Silicone-asbestos SA 90O C194O F

Dry locations

Asbestos and Varnished Cambric

AVA 110O C230O F

Dry locations only

TYPES OF INSULATORS

CONDUITS are circular raceways used to enclose wires and cables and are of metal or plastic (PVC).

3.3 CONDUITS

To protect the enclosed conductors from mechanical injury and chemical damage.

To protect people from shock hazards by providing a grounded enclosure.

To provide a system ground path.

To protect the surroundings against fire hazard as a result of overheating or short circuiting of the enclosed conductors.

To support the conductors.

TYPES OF STEEL CONDUITS

Heavy-wall steel conduits called “Rigid Steel Conduits” or RSC with an approximate thickness of 0.117 mm.

“Intermediate Metal Conduit” or IMC with thickness of 0.071 mm.

Thin-wall steel conduits named “Electric Metal Tubing” or EMT.

RSCs and IMCs use the same fitting, called condulets, and are threaded alike at the joints. EMTs are not threaded but use set screw and pressure fitting and are not recommended for embedding in concrete nor permitted in hazardous areas. IMCs yield a larger inside diameter (ID) for easier wire pulling and is lighter than the RSC.Standard length of steel conduits is 3 M or 10 ft.

3.4 RACEWAYS – are channels or wiring accessories so designed for holding wires, cables and bus bars that are either made of metal, plastic, or any insulating medium.

3.5 OUTLETS and RECEPTACLES – An outlet is a point in the wiring system at which current is taken to supply utilization equipment. It refers only to the box. A receptacle is the wiring device in which the utilization equipment (appliance) cord is plugged into.

•Convenience Outlet or Attachment Cap - the complete set-up which establishes connection between the conductor of the flexible cord and the conductors connected permanently to the receptacle.

•Lighting Outlet – is an outlet intended for direct connection to a lamp holder, lighting fixture, or pendant cord terminating in a lamp holder.

•Receptacle Outlet – is an outlet where one or more receptacles are installed.

3.6 SWITCHES – are devices for making, breaking, or changing conditions in an electrical circuit under the conditions of load which they are rated.TYPE OF SWITCH – ACCORDING TO VOLTAGESwitches are rated as 250V, 600V,or 5KV as required. TYPE OF SWITCH – ACCORDING

TO INTENSITY OF USE

1. Normal Duty (ND) – intended for normal use in light and power circuits as in general-purpose switches.

2. Heavy Duty (HD) – intended for frequent interrupting.

3. Light Duty (LD) –intended to connect the loads occasionally, such as service switches.

TYPE OF SWITCH - ACCORDING TO TYPE OF SERVICE

1. Service Switch – intended to disconnect all the electric service in the building except emergency equipment. This may comprise one to six properly rated switches that are assembled into a switchboard.

2. Power Switches –

a) General –purpose switches – are intended for use in general distribution and branch circuits.

b) Disconnecting or isolating switches – are intended for disconnecting or isolating circuits; used for circuits rated at more than 600 volts.

a) General–purpose switches – are single-pole or double-pole switches for the general purpose use of connecting or cutting-off circuits for the control of lamps or other loads from a single point.

b) Three-way switches – are used where it is desired to control lamps from two different points, as in a stairwell.

c) Four-way switches – are used in conjunction with two 3-wire switches where it is desired to control lamps from three or more desired points.

3. Wiring Switches – include all the relatively small switches that are employed in interior wiring installations for the control of branch circuits, individual lamps or appliances.

d) Electrolier or multi-circuit switches – are used for the control of lights in multi-lamp fixtures so that one lamp or set of lamps may be turned on alone or in combination with other lamps.

e) Momentary contact switches – are used where it is desired to connect or cut-off a circuit for only a short duration. The switch is provided with a spring so that it will return to its original position as soon as the handle or button is released.

f) Dimmer switches – a rheostat[1] or similar device for regulating the intensity of an electric light without appreciably affecting spatial distribution. Also called a dimmer.Wiring switches may either be the flush type, surface type or the pendant type.

TYPE OF SWITCH - ACCORDING TO OPERATION MECHANISM

Wiring switches may also be classified according to the operating mechanism as:

1. Rotary switch2. Push-button switch3. Toggle or tumbler switch

TYPE OF SWITCH - ACCORDING TO NUMBER OF POLES AND THROWS

1. Poles – that part of the switch which is used for making or breaking of a connection and which is electrically insulated from other contact making or breaking parts.

2. Throws - a single throw switch is one which will make a closed circuit only when the switch is thrown in one position. A double throw switch will make a closed circuit when thrown in either of two positions.

SPECIAL SWITCHES

1. Time Controlled Switches – This device comprises a precision low speed miniature drive motor (timer) to which some type of electric contact-making device is connected.

2. Remote Control (RC) Switches – A contactor[1], or more specifically, a relay[2], that latches after being operated wireless from a distance.

3.Air Switch – a switch in which the interruption of a circuit occurs in air.

4. Knife Switch – a form of air switch in which a hinged copper blade

is placed between two contact clips.

5. Float Switch – a switch controlled by a conductor floating in a liquid.

6. Mercury Switch – an especially quiet switch that opens and closes an electric circuit by shifting a sealed glass tube of mercury so as to uncover or cover the contacts.

7. Key Switch – a switch operated only by inserting a key or a card. Also called a card switch.

8. Automatic Transfer Switch (ATS) – This device, an essential part of an emergency or standby service, is basically a double throw switch, generally 3-pole, so arranged that on failure of normal power, emergency service is automatically supplied.

3.7 WALL PLATES OR FACEPLATES - These are coverings for switches and wall outlets usually made of metal or of phenollic compound (Bakelite).

3.8 OVER-CURRENT CIRCUIT PROTECTIVE DEVICES – are devices whose sole purpose is to protect insulation, wiring, switches and other apparatus from overheating or burning, due to overloads, to faults or to short circuits, by automatically cutting off the circuit.

FUSE – is a device consisting of an alloy link of wire with a low melting temperature which is inserted in the circuit, in such a way, that all current which passes through the circuit, must also pass through this metal.

CIRCUIT BREAKERS– is an over-current protective device designed to function as a switch, or it can be manually tripped and thus act as a circuit switch. It breaks a circuit with an automatic tripping device without injury to itself.

GROUND FAULT CIRCUIT INTERRUPTERS (GFCI or GFI) – is an over current protective device that will provide ground fault protection as well as function as an ordinary circuit breaker.

PANELBOARDS – popularly known as “panel” or “electrical panel”, it is simply the box wherein the protective devises are housed from which the circuits and bus bars terminate.

SWITCHBOARDS – are free standing assemblies of switches, fuses, and/or circuit breakers whose function normally is to provide switching and feeder protection to a number of circuits connected to a main source.

UNIT SUBSTATIONS – (Transfer Load Centers) an assembly of primary switch-fuse-breaker, step-down transformer, meters, controls, bus bars and secondary switchboard. It is used to supply power from a primary voltage line to any large facility.

4.1 WIRING METHODSKNOB AND TUBE WIRING – an obsolete wiring system consisting of single insulated conductors secured to and supported on porcelain knobs and tubes. When wires run through walls, they are inserted into a nonmetallic fire-resistant tubing called a loom.RIGID METAL CONDUIT WIRING – is the best and most expensive among the usual type of wiring. Its advantages are:1. it is fireproof;2. moisture proof;3. it is mechanically strong so that nails cannot be driven through it and it is not readily deformed by blows;4. it resists the normal action of cement when embedded in concrete or masonry.

4. WIRING SYSTEMS

FLEXIBLE METAL CONDUIT WIRING – Its installation is much easier and quicker than that of rigid metal conduits. Unlike the rigid conduits which come in short lengths of 10 ft. (3 M), flexible metal conduit wiring comes in length of 25 ft – 250 ft (8 M – 83 M) depending on the size of the conduit.ARMORED CABLE WIRING (BX WIRING) – consists of rubber or thermoplastic covered wire protected from injury to a certain extent from dampness by one or two layers of flexible steel armor.SURFACE METAL RACEWAY WIRING – the wires are supported on a thin sheet steel casing. The raceway is installed exposed, being mounted on the walls or ceiling. Metal raceways must be continuous from outlet to outlet or junction box, designed especially for use with metal raceways.

FLAT CABLE ASSEMBLIES – a field installed rigidly mounted square structural channel (1 – 5/8” standard) designed to carry 2 to 4 conductors (No. 10 AWG) and will act as light duty (branch circuit) plug-in busways.

LIGHTING TRACK – a factory-assembled channel with conductors for one to four circuits permanently installed in the track that will act as light duty (branch circuit) plug-in busways.

CABLE TRAY / OPEN RACEWAY – is a continuous open support for approved cables. When used as a general wiring system, the cables must be self-protected, jacketed types, type TC.

FLOOR RACEWAYS – The NEC recognizes three types of floor raceways:

1. Underfloor Ducts (UF) installed beneath or flush with the floor. These underfloor ducts usually requires a triple duct system for power, telephone and signal cabling.

2. Cellular Metal Floor Raceway – Found usually in office landscaping, it is an integrated structural/electrical system in a cellular metal floor.

3. Precast Cellular Concrete – made of concrete cells fed from header ducts, which are normally installed in concrete fill above the hollow core structural slab or fed from the ceiling void below. The cells can be used for air distribution and for piping.

CEILING RACEWAY SYSTEMS – under-the-ceiling raceways composed of header ducts and distribution ducts separate for power and telephone cabling. They permit very rapid changes in layouts at low cost and are therefore particularly desirable in stores where frequent display transformations necessitate corresponding electrical facility adjustments.

PRE-WIRED CEILING DISTRIBUTION SYSTEMS – are ceiling raceways that are pre-wired in the factory and plugged in where required.

FEEDER

BRANCH CIRCUIT-CEILING/WALL

BRANCH CIRCUIT-FLOOR

3&4 WIRES CIRCUIT NO.MARK INDICATES 2 WIRES

CROSSING WIRES

CONNECTING WIRES

LIGHTING OUTLET CEILING

RECESSED CEILING OUTLETDASH INDICATES SHAPE OFFIXTURE

LIGHTING OUTLET WALL

FLUORESCENT LAMP

L LAMP HOLDER

PSLAMP HOLDER WITH PULL SWITCH

C

D

CLOCK OUTLET

DROP CORD OUTLET

F FAN OUTLET

R RADIO OUTLET

FLOOR OUTLET

CONVENIENCE OUTLET SPLIT-WIRED

DUPLEX CONVENIENCE OUTLET

WEATHER PROOF OUTLETWP

SOUTLET AND SWITCH

RRANGE OUTLET

SPECIAL PURPOSE OUTLET

refREFRIGERATOR OUTLET

PUSH BUTTON

BELL

BUZZER

CHIMECH

ANNUNCIATOR

LIGHTING PANEL

POWER PANEL

FUSE

WH WATT-HOUR METER

T TRANSFORMER

J JUNCTION BOX

GROUND

ELECTRICAL SYMBOLS

LIGHTING LAYOUT PLAN

POWER LAYOUT PLAN

ELECTRICAL REGULATIONSBY PD 1096

1. General Locational Requirements in Towns, Subdivisions, Human Settlements, Industrial Estates and the like.

Overhead transmission and/or distribution lines/systems including transformers, poles, towers and the like shall be located and installed following the latest standards of design, construction and maintenance but so as not to cause visual pollution and in the interest of public safety, convenience, good viewing and aesthetics, these may be located along alleys or back streets.

2.Location of Poles and Clearances of Power Lines along Public Roads.

2.1 All poles erected on public roads shall be covered by Approved Pole

Location (APL) plan from the Municipal Engineer.

2.2 Poles and transformer supports shall be located not more than

500mm inside from the road right-of-way or property line, and

shall not obstruct the sidewalk, pedestrian path and/or the road

drainage canal or structure, existing or proposed.

≤ 500 mm

Property line

Pole

2.3 Primary lines shall have a minimum vertical clearance of 10 m from the crown of the pavement when crossing the highway and 7.5 m from the top of the shoulder or sidewalk when installed along the side of the highway or street in a highly urbanized area.

≥10 m≥7.5 m

2.4 Secondary, neutral and service lines shall have a minimum vertical clearance of 7.5 m from the crown of the road pavement when crossing the highway and from the top of the shoulder or sidewalk when installed along the side of the highway or street in highly urbanized area.

2.5 Clearances of Supporting Structures such as Poles, Towers and

others and their guys and braces measured from the nearest

parts of the objects concerned:A. From Fire Hydrants, not less than 5 m.B. From the Street Corners, where hydrants

are located at street corners, poles and towers

shall not be set so far from the corners as to

make necessary the use of flying taps which are inaccessible from the poles.

C. From Curbs, not less than 150 mm measured from

the curb away from the roadway.

≥5 m≥150 mm

3. Attachments on and Clearances from Buildings

3.1 Attachments for support of power lines and cables, transformers and other

equipment and/or communications lines installed on buildings shall be

covered by an Approved Attachment Plan from the local Building Official.

3.2 Where buildings exceed 15 m in height, overhead lines shall be arranged

where practicable so that a clear space or zone at least 2 m wide will be

left, either adjacent to the building or beginning not over 2.5 m from the

building, to facilitate the raising of ladders where necessary for fire

fighting. 2 - 2.5 m

Pole≥ 15 m

4. Open Supply Conductors Attached to Buildings

Where the permanent attachment of open supply conductors of any class to buildings is necessary for an entrance such conductors shall meet the following requirements:

4.1 Conductors of more than 300 volts to ground shall not be carried along or

near the surface of the buildings unless they are guarded or made

inaccessible.

4.2 To promote safety to the general public and to employees not authorized

to approach conductors and other current-carrying parts of electric supply

lines, such parts shall be arranged so as to provide adequate clearance

from the ground or other space generally accessible, or shall be provided

with guards so as to isolate them effectively from accidental contact by

such persons.

4.3 Undergrounded metal-sheathed service cables, service conduits, metal

fixtures and similar noncurrent-carrying parts, if located in urban districts

and where liable to become charged to more than 300 volts to ground,

shall be isolated or guarded so as not to be exposed to accidental contact

by unauthorized persons. As an alternative to isolation or guarding,

noncurrent-carrying parts shall be solidly or effectively grounded.

4.4 Clearance of wires from building surface shall be not less than those required Table II.

4.5 Supports over buildings. Service-drop conductors passing over a roof shall be securely supported by substantial structures. Where practicable, such supports shall be independent of the building.

Voltage of Supply Conductors

Horizontal Clearance in

Meters

Vertical Clearance in Meters

300 to 8,700 volts 1.0 2.5

8,700 to 15,000 volts

2.5 2.5

15,000 to 50,000 volts

3.0 3.0

> 50,000 volts 3.0 + 10 mm per Kv in excess

3.0 + 10 mm per Kv in excess

5. Conductors Passing By or Over Buildings

5.1 Minimum Clearances. Unguarded or accessible supply conductors carrying voltages in excess of 300 volts may be run either beside or over buildings. The vertical or horizontal clearance to any building or its attachments (balconies, platforms, etc.) shall be as listed below. The horizontal clearance governs above the roof level to the point where the diagonal equals the vertical clearance requirement. This rule should not be interpreted as restricting the installation of a trolley contact conductor over the approximate center line of the track it serves.

5.2 Guarding of Supply Conductors/Supply of Conductors of 300 volts or more shall be properly guarded by grounded conduit, barriers, or otherwise, under the following conditions:

1. Where the clearances set forth in Table II above cannot be obtained.

2. Where such supply conductors are placed near enough to windows, verandas, fire escapes, or other ordinarily accessible places within the reach of persons.

5.3 Where the required clearances cannot be obtained, supply conductors shall be of Grounded Metallic Shield, Jacketed Primary Cables grouped or bundled and supported by grounded messenger wires.

V-

≥V

Clearance of line conductors from -

Communication LInes Supply LInes

In general On jointly used poles

In general (0 to 8700 volts)

On jointly used poles (0 to 8700 volts)

Exceeding 8700 volts, add for each 1000 volts of excess

Vertical and lateral conductors of the same circuit

75 mm 75 mm 75 mm 75 mm 6.25 mm

Vertical and lateral conductors of other circuits

75 mm 75 mm 150 mm 150 mm 10 mm

Span and guy wires attached to same pole: general

75 mm 150 mm 150 mm 150 mm 10 mm

Span and guy wires attached to same pole: when parallel to line

75 mm 150 mm 300 mm 300 mm 10 mm

Lightning protection wires parallel to line: surfaces of cross arms

75 mm 75 mm 75 mm 75 mm 5 mm

Lightning protection wires parallel to line: surfaces of poles

75 mm 125 mm 75 mm 125 mm 5 mm

6. Clearance of Service Drops

6.1 Service drop conductors shall not be readily accessible and when not in

excess of 600 volts, shall conform to the following:

a. Clearances over roof. Conductors shall have a clearance of not less

than 2.5m from the highest point of roofs over which they pass with

the following exceptions:≥ 2.5 mHighest point

Service Drop Conductor< 600 volts

Exception No. 1. Where the voltage between conductors does not exceed 300 volts and the roof has a slope of not less than 100mm in 300mm, the clearance may not be less than 1m.

≥1 mHighest point

Service Drop Conductor≤300 volts

Slope ≥ 1:3

Exception No. 2. Service drop conductors of 300 volts or less which do not pass over other than a maximum of 1.2m of the overhang portion of the roof for the purpose of terminating at a through-the-roof service raceway or approved support may be maintained at a minimum of 500mm from any portion of the roof over which they pass.

≤ 1.2 mHighest point

Service Drop Conductor≤ 300 volts

≥500mm

6.2 Clearance from the Ground. Conductors shall have a clearance of not less than 3m from the ground or from any platform or projection from which they might be reached.

conductor

platform≥ 3 m

6.3 Clearance from Building Openings. Conductors shall have a horizontal clearance of not less than 1m from windows, doors, porches, fire escapes, or similar locations and shall be run at least 500mm above the top level of a window or opening.

window

≥ 500mm

≥ 1 m

6.4 Service Drop of communication lines, when crossing a street, shall have a clearance of not less than 5.5 m from the crown of the street or sidewalk over which it passes.

≥ 5.50 m ≥5.50 m

Service drop of communication line

Service Drop of communication lines shall have a minimum clearance of 3m above ground at its point of attachment to the building or pedestal.

≥3m protector

≥3m

6.5 No parts of swimming and wading pools shall be placed under existing service drop conductors or any other over-head wiring; nor shall such wiring be installed above the following:

a. Swimming and wading pools and the area extending 3m outward horizontally from the inside of the walls of the pool.

b. Diving Structuresc. Observation stands, towers or platforms

Swimming pool

Service drop conductor

≥ 3 m

7. Wiring Methods

Service entrance conductors extending along the exterior or entering buildings or other structures shall be installed in rigid steel conduit or asbestos cement conduit or concrete encased plastic conduit from point of service drop to meter socket and from meter socket to the disconnecting equipment. However, where the service entrance conductors are protected by approved fuses or breakers at their outer ends (immediately after the service drop or lateral) they may be installed in any of the recognized wiring methods.

7.1 Abandoned Lines and/or portions of lines no longer required to provide

shall be removed.

7.2 Power or communication poles, lines, service drops and other line

equipment shall be free from any attachment for antennas, signs,

streamers and the like.

7.3 Metallic sheaths or jackets of overhead power or communication cables

shall be grounded at a point as close as possible to ground level whenever such cables change from overhead to underground installations.

8. Transformers

8.1 Oil-insulated Transformers Installed Outdoors. Combustible material,

combustible buildings and parts of buildings, fire escapes, door and

window openings shall be safeguarded from fires originating in oil-

insulated transformers installed on, attached to, or adjacent to a building

or combustible material. Space separations, fire-resistant barriers and

enclosures which confine the oil of a ruptured transformer tank are

recognized safeguards. One or more of these safeguards shall be applied

according to the degree of hazard involved in cases where the transformer

installation presents a fire hazard. Oil enclosures may consist of fire-

resistant dikes, curbed areas or basins, or trenches filled with coarse,

crushed stone. Oil enclosures shall be provided with trapped drains in

cases where the exposure and the quantity of oil involved are such that

removal of oil is important.

Trench allaround

Exterior Oil-insulatedTransformer

8.2 Dry-Type Transformers Installed Indoors. Transformers rated 112-1/2 KVA or less shall have separation of at least 300mm from combustible material unless separated there from by a fire-resistant heat-insulating barrier or unless of a rating not exceeding 600 volts and completely enclosed except for ventilating openings.

Dry-type transformer112-1/2 Kva or less

≥ 300mm

Combustible Wall

8.3 Askarel-Insulated Transformers Installed Indoors. Askarel-insulated transformers rated in excess of 25 KVA shall be furnished with a pressure relief vent. Where installed in a poorly ventilated place they shall be furnished with a means for absorbing any gases generated by arcing inside the case, or the pressure relief vent shall be connected to a chimney or flue which will carry such gases outside the building. Askarel-insulated transformers rated more than 35,000 volts shall be installed in a vault.

Transformers of more than 112-1/2 KVA rating shall be installed in a transformer room of fire-resistant construction unless they are constructed with Class B (80ºC rise) or Class H (150ºC rise) insulation, and are separated from combustible material not less than 1.85m horizontally and 3.7m vertically or are separated there from by a fire-resistant heat-insulating barrier.

Transformers rated more than 35,000 volts shall be installed in a vault.

Dry-type transformer112-1/2 Kva or less

≥ 1.85 m

CombustibleWall

Combustible ceiling

≥ 3.70 m

vault

Transformer morethan 35,000 volts

8.4 Oil-Insulated Transformers Installed Indoors. Oil-insulated transformers shall be installed in a vault constructed as specified in this Section except as follows:

1. NOT OVER 112-1/2KVA TOTAL CAPACITY. The provisions for transformer vaults specified in Section 9.3 of this Rule apply except that the vault may be constructed of reinforced concrete not less than 100mm thick.

2. NOT OVER 600 VOLTS. A vault is not required provided suitable arrangements are made where necessary to prevent a transformer oil fire igniting other materials, and the total transformer capacity in one location does not exceed 10 KVA in a section of the building classified as combustible, or 75 KVA where the surrounding structures is classified as fire-resistant construction.

> 100mm thick reinforced concrete vault

oil insulated transformer< 112-1/2 KVa

8.5 Guarding. Transformers shall be guarded as follows:

1. MECHANICAL PROTECTION. Appropriate provisions shall be made to minimize the possibility of damage to transformers from external causes where the transformers are located exposed to physical damage.

2. CASE OR ENCLOSURE. Dry-type transformers shall be provided with a non-combustible moisture resistant case or enclosure which will provide reasonable protection against accidental insertion of foreign objects.

3. EXPOSED LIVE PARTS. The transformer installation shall conform with the provisions for guarding of live parts in PEC Rule 1056.

4. VOLTAGE WARNING. The operating voltage of exposed live parts of transformer installations shall be indicated by signs or visible markings on the equipment or structures.

3. FURNACE TRANSFORMERS. Electric furnace transformers of a total rating not exceeding 75 KVA may be installed without a vault in a building or room of fire-resistant construction provided suitable arrangements are made to prevent a transformer oil fire spreading to other combustible material.

4. DETACHED BUILDING. Transformers may be installed in a building which does not conform with the provisions specified in this Code for transformer vault, provided neither the building nor its contents present fire hazard to any other building or property, and provided the building is used only in supplying electric service and the interior is accessible only to qualified persons.

9. Provisions for Transformer Vaults

9.1 New Building. New buildings requiring an expected load demand of 200KVA or above shall be provided with a transformer vault, except

that transformers may be mounted on poles or structures within the

property if enough space is available, provided that all clearances required can

be obtained and no troublesome contamination on insulators, bushings,

etc. can cause hazards and malfunctioning of the equipment.150 mm for R.C

200 mm for Brick300 mm for Load bearing CHB

200 Kva or moreWall:20 mm thick plaster2-1/2 hours fire rating

Floor:100mm thick 2-1/2 hours fire rating

9.2 Location. Transformer and transformer vaults shall be readily accessible to qualified personnel for inspection and maintenance. Vaults shall be located where they can be ventilated to the outside air without using flues or ducts wherever such an arrangement is practicable.9.3 Walls, Roof and Floor. The walls and roofs of vaults shall consist of reinforced concrete not less than 150mm thick, masonry or brick not less than 200mm thick, or 300mm load bearing hollow concrete blocks. The inside wall and roof surface of vaults constructed of hollow concrete blocks shall have a coating of cement or gypsum plaster not less than 20mm thick. The vault shall have a concrete floor not less than 100mm thick. Building walls and floor which meet these requirements may serve for the floor, roof and one or more walls of the vaults. Other forms of fire-resistive construction are also acceptable provided they have adequate structural strength for the conditions and a minimum fire resistance of two and one half hours according to the approved Fire Test Standard. The quality of the material used in the construction of the vault shall be of the grade approved by the Building Official having jurisdiction.

9.4 Doorways. Any doorway leading from the vault into the building shall be protected as follows:

1. TYPE OF DOOR. Each doorway shall be provided with a tight-fitting door of a type approved for openings in such locations by the authority enforcing this Code.

2. SILLS. A door sill or curb of sufficient height to confine within the vault, the oil from the largest transformer shall be provided and in no case shall the height be less than 100mm.

3. LOCKS. Entrance doors shall be equipped with locks, and doors shall be kept locked, access being allowed only to qualified persons. Locks and latches shall be so arranged that the door may be readily and quickly opened from the inside.

10.Ventilation. Ventilation shall be adequate to prevent a transformer temperature

in excess of the prescribed values.

1. LOCATION. Ventilation openings shall be located as far away as

possible from doors, windows, fire escapes and combustible material.

2. ARRANGEMENT. Vaults ventilated by natural circulation of air may have

roughly half of the total area of openings required or ventilation in one or more

openings near the floor and the remainder in one or more openings in the roof or in the sidewalls near the roof; or all of the area required for ventilation may be provided in one or more openings in or near the roof.

3. SIZE. In the case of vaults ventilated to an outdoor area without using ducts or flues the combined net area of all ventilating openings after deducting the area occupied by screens, grating, or louvers, shall be not less than 0.006 sqmm per KVA of transformer capacity in service, except that the net area shall be not less than 0.1 sqm for any capacity under 50 KVA.

4. COVERING. Ventilation openings shall be covered with durable gratings, screens, or louvers, according to the treatment requirement required in order to avoid unsafe conditions.

5. DAMPERS. Where automatic dampers are used in the ventilation openings of vaults containing oil-insulated transformers, the actuating device should be made to function at a temperature resulting from fire and not a temperature which might prevail as a result of an overheated transformer or bank of transformers. Automatic dampers should be designed and constructed to minimize the possibility of accidental closing.

6. DUCTS. Ventilating ducts shall be constructed of fire resistant material.

7. DRAINAGE. Where practicable, vaults containing more than 100KVA transformer capacity shall be provided with a drain or other means which will carry off any accumulation of oil or water in the vaults unless local conditions make this impracticable.

8. WATER PIPES AND ACCESSORIES. Any pipe or duct system foreign to

the electrical installation should not enter or pass through a transformer vault. Where the presence of such foreign system cannot be avoided, appurtenances thereto which require maintenance at regular intervals shall not be located inside the vault. Arrangements shall be made where necessary to avoid possible trouble from compensation, leaks and breaks in such foreign system. Piping or other facilities provided for fire protection or for water-cooled transformers are not deemed to be foreign to the electrical installation.

11.Capacitors.

1. Application. This section applies to installation of capacitors on electric

circuits in or on buildings. Exception No. 1. Capacitors that are components of other

apparatus shall conform to the requirements for such apparatus. Exception No. 2. Capacitors in hazardous locations shall comply

with additional requirements in PEC Section 400-415.

2. Location. An installation of capacitors in which any single unit contains

more than three gallons of combustible liquid shall be in a vault conforming

to part C of PEC Section 319.

3. Mechanical Protection. Capacitors shall be protected from physical damage

by location or by suitable fences, barriers or other enclosures.

4. Cases and Supports. Capacitors shall be protected from physical damage by

location or by suitable fences, barriers or other enclosures.

5. Transformers Used with Capacitors. Transformers which are components of

capacitor installations and are used for the purpose of connecting the

capacitor to a power circuit shall be installed in accordance with PEC Section

319. The KVA rating shall not be less than 135 per cent of the capacitor

rating in Kva.

12.Emergency Systems

1. The provisions of this Section shall apply to the installation, operation and maintenance of circuits, systems and equipment intended to supply illumination and power in the event of failure of the normal supply or in the event of accident to elements of a system supplying power and illumination essential for safety to life and proper where such systems or circuits are required by the Fire Code, or by any government agency having jurisdiction.

Emergency systems are generally installed in places of assembly where artificial illumination is required, such as buildings subject to occupancy by large numbers of persons, hotels, theaters, sports arenas, hospitals and similar institutions. Emergency systems provide power for such functions as refrigeration, operation of mechanical breathing apparatus, ventilation essential to maintain life, illumination and power for hospital room, fire alarm systems, fire pumps, industrial processes where current interruption would produce serious hazards, public address systems and other similar functions.

2. All requirements of this Section shall apply to emergency systems.

3. All equipment for use on emergency systems shall be properly approved.

4. Tests and Maintenance

a. The authority having jurisdiction shall conduct or witness a test on the complete system upon completion of installation, and periodically afterwards.

b. Systems shall be tested periodically in accordance with a schedule acceptable to the authority having jurisdiction to assure that they are maintained in proper operating condition.

c. Where the battery systems or unit equipment are involved, including batteries used for starting or ignition in auxiliary engines, the authority having jurisdiction shall require periodic maintenance.

d. A written record shall be kept of such tests and maintenance.

5. Emergency systems shall have adequate capacity and rating for the emergency operation of all equipment connected to the system.

6. Current supply shall be such that in the event of failure of the normal supply to or within the building or group of buildings concerned, emergency lighting or emergency power, will be immediately available. The supply system for emergency purposes may be composed one or more of the types of systems covered in Section 12.7 to Section 12.10 of this Rule. Unit equipment in accordance with Section 12.21 shall satisfy the applicable requirements of this Section.

Consideration must be given to the type of service to be rendered; whether for short duration, as for exit lights of a theater, or for long duration, as for supplying emergency power and lighting during long periods of current failure from trouble either inside or outside the buildings, as in the case of a hospital.

Assignment of degree of reliability of the recognized emergency supply system depends upon the careful evaluation of the variables of each particular installation.

7. A storage battery of suitable rating and capacity shall supply, by means of a service installed according to Section 200 of the PEC and maintained at not more than 90 per cent of system voltage, the total load of the circuits supplying emergency lighting and emergency power for a period of at least ½ hour.

8. A generator set driven by some form of prime mover, with sufficient capacity and proper rating to supply circuits carrying emergency lighting or lighting and power, equipped with suitable means for automatically starting the prime mover on failure of the normal service shall be provided. For hospitals, the transition-time from instant of failure of the normal power source to the emergency generator source shall not exceed ten seconds. (See Section 12.4)

9. There shall be two services, each in accordance with Section 200 of the PEC, widely separated electrically and physically to minimize the possibility of simultaneous interruption of power supply arising from an occurrence within the building or group of buildings served.

10.Connections on the line side of the main service shall be sufficiently separated from said main service to prevent simultaneous interruption of supply through an occurrence within the building or group of buildings served.

11. The requirements of Section 12.5 and Section 12.6 also apply to installations where the entire electrical load on a service or sub-service is arranged to be supplied from a second source. Current supply from a standby power plant shall satisfy the requirements of availability in Section 12.6.

12.Audible and visual signal devices shall be provided, where practicable, for the following purposes:

a. To give warning of dearrangement of the emergency or auxiliary source.

b. To indicate that the battery or generator set is carrying a load.

c. To indicate when a battery charger is properly functioning.

13. Only appliances and lamps specified as required for emergency use shall be supplied by emergency lighting circuits.

14. Emergency illumination shall be provided for all required exit lights and all other lights specified as necessary for sufficient illumination.Emergency lighting systems should be so designed and installed that the failure of any individual lighting element, such as the burning out of a light bulb, shall not leave any area in total darkness.

15.Branch circuits intended to supply emergency lighting shall be so installed as to provide service immediately when the normal supply for lighting is interrupted. Such installations shall provide either one of the following:

a. An emergency lighting supply, independent of the general lighting

system with provisions for automatically transferring to the emergency

lights by means of devices approved for the purpose upon the event of

failure of the general lighting system supply.

b. Two or more separate and complete systems with independent power

supply, each system providing sufficient current for emergency lighting

purposes. Unless both systems are used for regular lighting purposes

and are both lighted, means shall be provided for automatically

energizing either system upon failure of the other. Either or both

systems may be part of the general lighting system of the protected

occupancy if circuits supplying lights for emergency illumination are

installed in accordance with other Section of this Rule.

16. For branch circuits which supply equipment classed as emergency, there shall be an emergency supply source to which the load will be transferred automatically and immediately upon the failure of the normal supply.

17.Emergency circuit wiring shall be kept entirely independent of all other wiring and equipment and shall not enter the same raceway, box or cabinet with other wiring except:

a. In transfer switches, orb. In exit or emergency lighting fixtures supplied from two (2)

sources.

18. The switches installed in emergency lighting circuits shall be so arranged that only authorized persons have control of emergency lighting, except:

a. Where two or more single throw switches are connected in parallel to

control a single circuit, at least one of those switches shall be accessible

only to authorized persons.b. Additional switches which act only to put emergency lights

into operation but not to disconnect them may be permitted.

Switches connected in series and three- and four-way switches shall not be allowed.

19. All manual switches for controlling emergency circuits shall be located at the most accessible place to authorized persons responsible for their actuation. In places of assembly, such as theaters, a switch for controlling emergency lighting systems shall be located in the lobby or at a place conveniently accessible there from.In no case shall a control switch for emergency lighting in a theater for motion picture projection be placed in the projection booth or on the stage. However, where multiple switches are provided, one such switch may be installed in such locations and so arranged that it can energize but not disconnect for the circuit.

20. Lights on the exterior of the building which are not required for illumination

when there is sufficient daylight may be controlled by an automatic light

actuated device approved for the purpose.

21. In hospital corridors, switching arrangements to transfer corridor lighting in

patient areas of hospitals from overhead fixtures to fixtures designed to provide

night lighting maybe permitted, provided that the switching system is so

designed that switches can only select between two sets of fixtures but cannot

extinguish both sets at the same time.

22.The branch circuits over current devices in emergency circuits shall be

accessible to authorized persons only.

23. Where permitted by the authority having jurisdiction, in lieu of other methods specified elsewhere in this Section, individual unit equipment for emergency illumination shall consist of:

a. Batteryb. Battery charging means, when a storage battery is usedc. One or more lamps, andd. A relaying device arranged to energize the lamps

automatically upon failure of the normal supply to the building

The batteries shall be of suitable rating and capacity to supply and maintain, at not less than 90 per cent of rated lamp voltage, the total lamp load associated with the unit for a period of at least ½ hour. Storage batteries, whether of the acid or alkali type, shall be designed and constructed to meet the requirements of emergency service. Lead-acid type storage batteries shall have transparent jars.

Unit equipment shall be permanently fixed in place and shall have all wiring to each unit installed in accordance with the requirements of any of the wiring methods discussed in Chapter II of the PEC. They shall not be connected by flexible cord. The supply circuit between the unit equipment and the service, the feeders or the branch circuit wiring shall be installed as required by Section 12.17. Emergency illumination fixtures which obtain power from a unit equipment which are not part of the unit equipment shall be wired to the unit equipment as required by Rule 5257 of the PEC and in accordance with the one of the wiring methods described in Chapter II of the PEC.

13.Effectivity

1. All primary and secondary supply lines already existing shall comply with the provisions of this Rule within two (2) years from the effectivity of this Rule.2. Transformers to be installed on, attached to, or in buildings shall comply with the requirements of this Rule. Transformer installations already existing shall comply with the requirements within two (2) years from the effectivity of this Rule.3. Non-compliance with the provisions of this Rule shall be subject to the penal provisions in Section 213 of PD 1096.

THANK YOU