1.147640!section 1 electrical services

Estates and Buildings Division Serving the University Community

Section 1

Electrical Services

DESIGN GUIDE 2010 Edition

Section 1Electrical Services

Estates and Buildings Division DESIGN GUIDE Serving the University Community Expiry date: 31/07/10

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Contents 1.1 HIGH VOLTAGE SYSTEMS 1.1.1 General Description 1.1.2 Sub-Station Construction 1.1.2.1 Equipment to be provided within each sub-station 1.1.3 Design Standards 1.1.4 Transformers 1.1.5 Connection Arrangements 1.1.6 Calculations 1.1.7 Cable 1.1.8 Support & Fixings 1.1.9 Equipment & Locations 1.1.9.1 Ring Main Units 1.1.9.2 General Construction 1.1.10 Connection 1.1.11 Jointing 1.1.12 Protection Settings 1.1.13 Connection to BMS 1.1.14 Isolations 1.1.15 Earthing 1.1.16 Insulating Mat/Gloves 1.1.17 Testing 1.1.18 Handover 1.2 LOW VOLTAGE SYSTEMS 1.2.1 Low Voltage Distribution Panels 1.2.1.1 General Description 1.2.1.2 Connection/Isolation Arrangements 1.2.1.3 Calculations 1.2.1.4 Cable 1.2.1.5 Supports & fixings 1.2.1.6 Jointing 1.2.1.7 Protection settings 1.2.1.8 Connections to BMS 1.2.1.9 Labelling 1.2.1.10 Earthing 1.2.1.11 Metering 1.2.1.12 Record drawings 1.2.1.13 Permits 1.2.1.14 Inspection & Testing 1.2.2 Harmonic Filtering 1.2.2.1 General Description 1.2.2.2 Surveys 1.2.2.3 Connection Arrangements



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1.2.2.4 Cable 1.2.2.5 Containment System 1.2.2.6 Supports & Fixings 1.2.2.7 Equipment & Locations 1.2.2.8 Circuit Protection 1.2.2.9 Connections to BMS 1.2.2.10 Record Drawings 1.2.2.11 Permits 1.2.2.12 Testing, Commissioning & Certification 1.2.2.13 Labelling 1.2.3 Power Factor Correction 1.2.3.1 General Description 1.2.3.2 Surveys / Calculations 1.2.3.3 Connection Arrangements 1.2.3.4 Cable 1.2.3.5 Cable Supports & Fixings 1.2.3.6 Equipment & Locations 1.2.3.7 Circuit Protection 1.2.3.8 Connections to BMS 1.2.3.9 Record Drawings 1.2.3.10 Permits 1.2.3.11 Testing, Commissioning & Certification 1.2.3.12 Labelling 1.2.4 External & Amenity Lighting 1.2.4.1 Extent of Works 1.2.4.2 Drawings 1.2.4.3 Builders Work 1.2.4.4 Electricity Services 1.2.4.5 Earthing & Bonding 1.2.4.6 Cabling 1.2.4.7 Feeder Pillars/Control Boxes 1.2.4.8 Lighting Units 1.2.4.9 Fuse Gear 1.2.4.10 Switching Units 1.2.4.11 Lamp Control Gear 1.2.4.12 Painting 1.2.4.13 Labelling 1.2.4.14 Workmanship & Practice 1.2.4.15 Redundant Materials 1.2.4.16 Manufacturers Recommendations 1.2.4.17 Specifications 1.2.4.18 Notices 1.2.4.19 Testing 1.3 FIRE ALARM 1.3.1 General description 1.3.2 Site Reporting System 1.3.3 Conventional System 1.3.4 Standards 1.3.5 Fire Alarm Control Panel (FACP)



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1.3.5.1 Functional Description 1.3.5.2 Panel Construction 1.3.5.3 Panel Indications 1.3.5.4 Panel Controls 1.3.5.5 Software 1.3.5.6 Configuration 1.3.5.7 Remote Dial-up 1.3.5.8 Remote Terminals 1.3.5.9 Power Supplies 1.3.5.10 Additional System Components 1.3.6 Apollo Detectors & Devices 1.3.7 Hochiki Detectors & Devices 1.4 TELEPHONE 1.4.1 General Description 1.4.2 Cable 1.4.3 Supports & Fixings 1.4.4 Containment System 1.4.5 System Design 1.4.6 Equipment Specific 1.4.6.1 Analogue Equipment 1.4.6.2 VoIP Equipment 1.4.7 Connection Procedure 1.4.8 Record Drawings 1.4.9 Permits 1.4.10 Testing, Commissioning & Certification 1.5 DATA 1.5.1 General Description 1.5.2 Cable 1.5.2.1 UTP copper cabling 1.5.2.2 Single Mode fibre 1.5.2.3 Multimode fibre 1.5.3 Supports & Fixings 1.5.3.1 Cabinets and racking 1.5.3.2 UTP outlets 1.5.3.3 Cable ties 1.5.3.4 Comms Rack Patch Panels (UTP and fibre) 1.5.4 Containment System 1.5.4.1 UTP Copper Cabling Containment 1.5.5 System Design 1.5.6 Equipment Specific 1.5.6.1 Network Routers 1.5.6.2 Network Switches 1.5.6.3 Wireless Networking 1.5.6.4 SFP specifications 1.5.6.5 Media Convertors 1.5.7 Connection Procedure



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1.5.8 Record Drawings 1.5.9 Permits 1.5.10 Testing, Commissioning & Certification



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1.1 HIGH VOLTAGE SYSTEMS 1.1.1 General Description

This document is aimed at providing designers/consultants with the necessary information and Standards to be adopted when undertaking project work at the University of East Anglia. This document is not intended to replace detailed specifications for electrical installation and is not exhaustive. Consultants/designers of electrical installations should use this document to understand the methods and systems to which they need to satisfy when working on projects at the University. By establishing standard installation methods and the equipment to be utilised it is hoped to streamline the specification and designs process. The University operates and maintains a privately owned high voltage (11000v) network which supplies the main Campus with electricity via sub-stations, strategically located around the site. The main Campus has an 11000v intake point supplied by the local D.N.O (EDF) and this is the main artery supplying the Campus. In addition to the DNO supply the University has a Combined Heat and Power station capable of generating 3MVA which feeds into the existing network. The facility to export power back to the National Grid exists when a surplus of energy is being generated. There are a small number of generators which supply essential services which, in turn, maintain supplies during power failures.

1.1.2 Sub-Station Construction

Generally the construction of a new sub-station shall encompass the following:

be suitably dimensioned to allow free movement around transformers;

have two means of escape; have blast doors incorporated in the design; be stand alone construction; have cable ducts installed for HV and LV cables; incorporate gravel traps; be fit for purpose; designed to BS 7430.

1.1.2.1 Equipment to be provided within each sub-station:

Key Cabinet containing safety padlocks. First aid box. Telephone. Mimic diagram of HV network.



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Safety signs - Caution notice. Safety Locks. Log book. Danger & Caution notices. Safety Posters. Network outlet.

1.1.3 Design Standards

The electrical system installed within the University Campus is an 11kv 3-phase 50Hz earthed neutral system. The network must comply with the National Health Service Model Engineering Specification C45 Standard References. The materials, components and completed installations shall conform as applicable with the following Standards, including all amendments, current at the time of tendering. Construction products should comply with European Standards and Technical Specifications (ESTS), generally ISO series, shall be equally acceptable. Switchgear See Technical Index below:

ESI STANDARDS 12-8 Issue 2 1986 The application of the fuse links to 11kV and 6.6

kV/415 V distribution networks. 41-5 Issue 3 1983 Requirements for 12 kV distribution metal

enclosed indoor switchgear. 41-12 Issue 2 1975 Non-extensible ring main equipments. BRITISH STANDARDS BS 159 : 1992 Specification for high-voltage busbars and

busbar connections. BS 923 Guide to high-voltage testing techniques. Part 1 : 1990 General requirements. BS EN 60060-2: 1995 High voltage test techniques measuring systems BS 2692 Fuses for voltages exceeding 1000V a.c. Part 2 : 1956 Expulsion Fuses. Part 3 : 1990 Guide to the determination of short circuit power

factor. (Soon to be replaced by) BS EN 60282-1 : 1996 Current-limiting fuses.



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BS EN 60298 : 1996 Specification for a.c. metal-enclosed switchgear and control gear for rated voltages above 1 kV and up to and including 52 kV.

BS EN 60129 : 1994 Specification for alternating current

disconnectors and earthing switches. BS 5311 : 1996 Specification for high-voltage alternating-current

circuit-breakers. BS 5463 Specification for high-voltage switches. Part 1 : 1991 High-voltage switches for rated voltages above

1kV and less than 52 kV. Part 2 : 1991 Renumbered as BS EN 60265-2. BS 5472 : 1977 (1991) Specification for low-voltage switchgear and

control gear for industrial use. Terminal marking and distinctive number. General rules.

BS 5486 Low-voltage switchgear and control gear

assemblies. Part 11 : 1989 Specification for particular requirements of

fuseboards. BS EN 60255 Electrical relays. BS EN 60255-6 : 1995 Measuring relays and protective equipment. BS EN 60255-21 Vibrating shock, bump and seismic tests on

measuring relays and protection equipment. BS EN 60255-21-1 : 1996 Vibration tests (sinusoidal). BS EN 60255-21-2 : 1996 Shock and bump tests. BS EN 60255-21-3 : 1995 Seismic tests. BS EN 60255-22 Electrical disturbance tests for measuring

relays and protection equipment. EN 60255-22-2 : 1997 Electrostatic discharge tests. EN 60255-23 : 1997 Contact performance. BS EN 60439 Specification for low-voltage switchgear and

controlgear assemblies. BS EN 60439-1 : 1994 Specification for type-tested and partially type-

tested assemblies. BS EN 60439-2 : 1993 Particular requirements for busbar trunking

systems (busways).



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BS EN 60529 : 1992 Specification for degrees of protection provided by enclosures (IP code).

BS 6626 : 1985 Code of practice for the maintenance of electrical

switchgear and control-gear for voltages above 1 kV and up to and including 36 kV.

BS 7430 : 1991 Code of practice for earthing. ELECTRICITY COUNCIL Transformers

ESI STANDARDS 12-8 : 1976 Issue 1 The application of fuse links to 11 kV and 6.6

kV/415 V distribution networks. 35-1 : 1985 Issue 4 Distribution transformers (from 16 kVA to 1000

kVA). BRITISH STANDARDS BS 148 : 1984 Specification for unused mineral insulating oils

for transformers and switchgear. BS 171 Power transformers. Part 1 : 1978 General. Part 2 : 1978 Specification for temperature rise requirements. Part 3 : 1987 Specification for insulation levels and dielectric

tests. BS 2562 : 1979 Specification for cable boxes for transformers

and reactors. BS 2857 : 1976 Specification for nickel-iron transformer and

choke laminations. BS 3535 Isolating transformers and safety isolating

transformers. Part 1 : 1990 General requirements. Replaced by BS EN

60742 : 1996 but remains current for use with BS 3535 : Part 2.

Part 2 : 1990 Specification for transformers for reduced system voltage.

BS 7625 : 1993 Specification for voltage transformers. BS 7626 : 1993 Specification for current transformers. BS 5336 : 1976 Specification. Cores made of ferromagnetic

oxides for use in high flux density transformers.



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BS 5953 Guide on power transformers. Part 1 : 1980 Application of power transformers. BS 7735 : 1994 Guide to loading of oil-emersed power

transformers. GENERAL BS 88 Cartridge fuses for voltages up to and including

1000 V A.C. and 1500 V D.C. Part 1 : 1988 Specification of general requirements. Also

known as BS EN 60269-1 : 1994. Part 2 Specification for fuses by authorised persons

(mainly for industrial application). Section 2.1 : 1988 Supplementary requirements. Also known as BS

EN 60269-2 : 1995. Section 2.2 : 1988 Additional requirements for fuses with fuse-links

for bolted connections. Part 4 : 1988 Specification of supplementary requirements for

fuse-links for the protection of semi conductor devices.

Part 5 : 1988 Specification of supplementary requirements for fuse links for use in a.c. electricity supply networks.

BS 89 (Parts 1-9 : 1990) Direct acting indicating analogue electrical

measuring instruments and their accessories. BS 381C : 1996 Specification for colours for identification, coding

and special purposes. BS 697 : 1986 Specification for rubber gloves for electrical

purposes. BS 801 : 1984 Specification for composition of lead and lead

alloy sheaths of electric cables. BS 921 : 1976 Specification for rubber mats for electrical

purposes. BS 951 : 1986 Specification for clamps for earthing and bonding

purposes. BS 2754 : 1976 Memorandum. Construction of electrical

equipment for protection against electric shock. BS 3693 : 1992 Recommendations for design of scales and

indexes on analogue indicating instruments. BS 3941 : 1975 (1992) Specification for voltage transformers. BS EN 61184 : 1995 Specification for bayonet lamp holders.



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BS 5306 (Parts 1-7) Fire extinguishing installations and equipment on

premises. BS EN 61010-1 : 1993 Safety requirements for electrical equipment

for measurement, control and laboratory use. General requirements.

BS EN 60071 Insulation co-ordination. BS EN 60071-1 : 1996 Terms, definitions, principles and rules. BS EN 60071-2 : 1996 Application guide. BS 5685 Electricity meters. (8 Parts) Parts 1, 2, 3 & 4 are obsolescent. BS 5730 : 1979 Code of practice for maintenance of insulating

oil. BS 6480 : 1988 Specification for impregnated paper-insulated

lead or lead alloy sheathed electric cables of rated voltages up to and including 33000 V.

BS 6626 : 1985 Code of practice for maintenance of electrical

switchgear and controlgear for voltages 1 kV and up to and including 36 kV.

BS 7430 : 1991 Code of practice for earthing. BS 7863 : 1996 Recommendations for colour coding to indicate

the extinguishing media contained in portable fire extinguishers.

Health and Safety at WorkAct1974 Electricity Supply Regulations 1988 (as amended 1992 and 1994) Electricity at Work Regulations 1989 BS 7671: 1992 Requirements for Electrical Installations

1.1.4 Transformers

Transformers shall generally be floor mounted and be naturally ventilated within the enclosure built. Typical arrangement details listed below :

Rating kva 1250 Primary Voltage (No Load) Volts 11000 Secondary Voltage (No Load) Volts 433 Vector Group Dyn11



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Tapping Range/Steps on HV winding +/5% with 2.5% steps Tapping Switch Off Circuit Cooling ONAN Tank Breathing Reference Temperature C 75 Temperature Rise Oil/Winding C 55/65 No Load loss at normal rating Watts 2250 Load loss at normal rating Watts 17250 Impedance at normal rating % 5 Construction Data Total Weight Kg 3670 Insulating Liquid quantity Litres 760 Overall Length mm 1725 Overall Width mm 1725 Overall Height mm 1670 Termination Arrangements

1.1.5 Connection Arrangements

Connection and alterations to the Universitys High Voltage (HV) system are preferred utilising contractors already established on the Estates & Buildings contractors register. No T jointing will be permitted on any part of the HV network. Where joints are necessary these shall be of the in line, resin filled type and conform to current British and European Standards. Cables shall not be crossed or rolled within cable termination boxes unless appropriate screening and stress control arrangements exist or are fitted. All isolations will be carried out under the control of Estates & Buildings Authorised Person (AP) and requests shall be submitted in writing to the Universitys Electrical Design Engineer complete with risk assessments and Method Statements for the proposed works a minimum of 14 working days in advance. See Section 12.9 in Section 12.

1.1.6 Calculations

Requests to add additional load to any part of the existing HV network must be submitted in writing to the Universitys Electrical Design Engineer for approval. The designer/contractor responsible for the works must demonstrate a clear understanding of the electrical infrastructure by providing the following information:



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The total additional load to be applied to the HV network. The total additional load on the secondary of the

transformer. Adjustments required to the protection grading of HV

network. 1.1.7 Cable

All HV cabling shall have a red outer sheath and where buried direct shall have additional protection placed directly above such as plastic marker tiles. Warning tape shall be utilised when back filling along the entire length of the cable. The existing network is a mixture of 95mm sq 3 core copper swa and 185mm 3 core aluminium swa cable. All new installations shall be in copper with cores identified by colour or number. Only cables complying and carrying the appropriate British Standard mark shall be used.

1.1.8 Support & Fixings

HV cabling shall be adequately supported throughout its length where routed within buildings supplying ring main units and transformer supplies. Methods of support proposed shall be discussed prior to installation with the Universitys Electrical Design Engineer for approval. Any works undertaken by a contractor without the relevant sanction will be subject to rejection.

1.1.9 Equipment & Locations 1.1.9.1 Ring Main Units

Manufacturer Schneider RE2C Any new installation shall be pre-wired with the facility to connect on to the Universitys HV monitoring Building Management System (BMS).

1.1.9.2 General Construction

Ring Switch: 630A fault make/load break, spring assisted switches comprising 3 position units offering a main on/off/earth on function. The switch is naturally interlocked to prevent the unit from being switched from the main on to earth on position without first being in the off position. Selection of the main and earth position shall be made through a lever on the facia, which is only allowed to move if the switch is in the off position. Both ring switches shall be equipped with provisional wiring for function automation easing the retro-fitting of motor packs.



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Circuit breaker: The 200A spring assisted circuit breaker comprises a 3 position unit offering a main on/off/earth on function. The circuit breaker is naturally interlocked to prevent the unit from being switched from the main on to the earth on position without having first being in the off position. The selection of the main and earth positions are made through a lever on the facia, which is only allowed to move is the switch is in the off position:

Aux contacts 1NO + 1NC. Earth position selected 1NO. Earth ON 1NO.

Protection & control CB: Self powered IDMT overcurrent and earth fault relay, VIP 300. In accordance with IEC 60255 and BS142 Protection CTs - 200/1A class X. Setting range:

Overcurrent: 20-200A. Earth fault: 2-160A.

1.1.10 Connection

Before any work can commence on any part of the Universitys HV network the contractor must submit a specific Method Statement, Risk assessment and Programme of Works to the UEA Electrical Engineer. The names of the operatives and certification for their specialist area must also be submitted for approval. Contractors/consultants should note that the isolation of a sub-station has a considerable effect on the buildings supported and as such isolations should be scheduled during holiday periods. Minor alterations that do not result in transformers being isolated are less disruptive but will still require a minimum of two weeks notice. Isolations will be carried out by UEA Authorised Personnel only. Following isolation and earthing of a cable the contractor shall take control of only that part of the HV network. This shall be by the Universitys Permit to Work documentation. If the contractor wishes to use their own safety documentation then this will be in addition to the UEA Permit not a replacement of. See Section 12.9 in Section 12. All works will be in accordance with the relevant British Standard and a witnessed pressure test carried on completion of works. A current and valid test certificate shall be provided which lists the recorded tests and readings obtained.



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1.1.11 Jointing

No T jointing will be permitted on any part of the HV network. Where joints are necessary these shall be of the in line type and conform to current British and European Standards. The joints should also be resin filled and their position plotted on the Universitys CAD system.

1.1.12 Protection Settings

When a new sub-station is added into the existing HV network, or a transformer is replaced, a discrimination study must be undertaken in order to update the protection settings for the site. This must be handed to the UEA site engineer for approval and verification.

1.1.13 Connection to BMS

It is proposed that following the upgrade of the last three remaining oil filled ring main units the HV network will be connected and controlled via a BMS. This may form part of the existing TREND system or could possibly be a stand alone network. Proposals for new sub-stations must cater for this in their design and in providing all necessary infrastructure required to integrate into the Universitys system.

1.1.14 Isolations

Isolations will be carried out by UEA Authorised Personnel only. Following isolation and earthing of a cable the contractor shall take control of only that part of the HV network. This shall be by the Universitys Permit to Work documentation. All works will be in accordance with the relevant British Standard and a witnessed pressure test carried on completion of works. A current and valid test certificate shall be provided which lists the recorded tests, readings and the duration.

1.1.15 Earthing

The earthing system provided at any sub-station must attain an ohmic reading of less than 1 when isolated from the main network. How this is achieved is subject to discussions with the UEA Electrical Engineer. A connection can then be made, following an acceptable test, to the star point of the supply transformer providing a system neutral earth. Sub-station earthing must comply with BS7430. See Technical index.



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A minimum of two earth legs are to be installed which will form connection to the earthing mat/stake system. This is to facilitate routine testing/adjustments on a live network without the need for isolating the sub-station. Within each sub-station an earth bar shall be installed 450mm above finished floor level and supported off the wall by isolators. The earth bar shall be a hard drawn copper bar and of sufficient size to accommodate:

HV switch frame. LV switch frame. Transformer frame earth. LV Generator frame earth. Transformer neutral earth. LV Generator neutral earth.

1.1.16 Insulating Mat/Gloves

Rubber matting shall be provided and conform to BS 921. These shall be adequately sized and located to provide authorised personnel from making contact with a non-insulating floor with either or both feet.

1.1.17 Testing

A full visual inspection of plant installed shall be carried out prior to any testing in order to make sure equipment is in a serviceable condition. This will form part of the procedure for testing , inspecting and setting into place. Testing and commissioning shall be as detailed in National Health Services Model Engineering Specification C45

1.1.18 Handover

Prior to handover all test documentation shall be presented to the Universitys Electrical Engineer for verification/comments. All drawings, plans and files shall be complete and presented as stated in the contract documents. See Section 18.

1.2 LOW VOLTAGE SYSTEMS 1.2.1 Low Voltage Distribution Panels 1.2.1.1 General Description



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The University operates and maintains a privately owned high voltage (11000v) network which supplies the main Campus with electricity via sub-stations strategically located around the site. The main Campus has an 11000v intake point supplied by the local D.N.O (EDF) and this is the main artery supplying the Campus. In addition to the DNO supply the University has a Combined Heat and Power station capable of generating 3MVA which feeds into the existing network. The facility to export power back to the National Grid exists when a surplus of energy is being generated. There are a small number of generators which supply essential services which maintain supplies during power failures. NOTE: When designing alterations to existing services careful consideration must be give to establishing whether or not dual supplies are present in the form of a generator backed services. A large proportion of the University is served by the original main low voltage distribution panels (1960s design and construction ) which places restrictions on capacity and load placed upon them. The form rating is poor on some of the older panels so caution should be exercised should it be necessary to remove any panel covers. Access to low voltage switch rooms is restricted to persons deemed competent within these areas and familiar with The Electricity at Work Regulations 1989, BS7671 and Health and Safety at Work Act 1974. Access for the purpose of feasibility/load studies is by prior arrangement via a member of the projects office. Simply arriving on site expecting keys to be made available will result in a lengthy delay or may require the visit to be rescheduled.

1.2.1.2 Connection/Isolation Arrangements

Single Phase loads not exceeding 3kw Please refer to Electrical Isolations & Permit section for procedures For single loads not exceeding 3kw and being supplied from an existing circuit or dedicated radial circuit, an electrical isolation Permit will not be required. This is providing the new load is being connected via an existing fused connection unit or other double pole isolation device. For all other connections an electrical isolation Permit must be obtained prior to any works within a distribution board/panel taking place.



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Existing distribution shall be left with spare capacity so consideration must be given to the possibility of replacing a distribution board to facilitate future demands. Distribution boards no longer complying with current legislation will also require replacement in order to provide valid certification. Any persons undertaking this type of work must be competent when working or operating low voltage electrical equipment and comply with the Universitys Health & Safety rules, i.e. provide adequate and appropriate risk assessments and Method Statements for the proposed works. See Section 12. The new circuit shall be clearly labelled within the distribution board and cross referenced at the load end of the supply. On completion of works the contractor shall submit a current and valid certificate complying with the requirements of the current edition of the Requirements for Electrical Installations BS 7671: The format of the certification shall be either NICEIC or ECA. Certification is to be submitted to the Universitys Electrical Design Engineer for approval.

For loads in excess of 3kw the following shall apply; that prior to any connection/isolation the following information shall be submitted to the Project Manager:

Accurate evaluation of anticipated load. The date when connection is required. Single or three phase load. Type of load to be connected. The location of the new load. Origin of service distribution board load to be taken from.

It is important to consider the effect the additional loads will have on the existing electrical infrastructure. Consultants/designers must undertake and submit valid feasibility studies to support their recommendations when introducing additional electrical loads. These should be submitted and discussed with the Universitys Electrical Engineer prior to any work commencing on site. If this process is omitted and subsequent problems arise, any additional cost in rectifying the situation will rest firmly with the consultants/designers of the installation. Isolations to facilitate connection of an electrical load need careful planning as a large proportion of the building is research orientated. This places additional constraints on contractors when isolations are required. Typically this type of interruption will be arranged over weekend periods, or out of normal working hours, to minimise disruption to users bases on the area where the connection is to be made.



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Consideration must also be given to other services which use an electrical supply to maintain services such as:

CCTV. Site wide IT networks. Fume cupboard extract. Localised IT Network. Fire alarm panels. Intruder alarm panels. Wi Fi IT systems. University BMS.

This list is not exhaustive but designed to give an idea of the disruption that must be avoided when isolating sub-mains to buildings or distribution boards. The Estates department have two account managers who can help when dealing with such matters:

Trevor Smith. Corinne Ashwell.

If contact is made at an early stage a co-ordinated approach can be made when isolations are required. The UEA operate a Permit to Work system for electrical works and contractors must comply with this without fail. See Section 12.9 in Section 12. Any persons undertaking this type of work must be competent when working or operating low voltage electrical equipment and comply with the Universitys Health & Safety rules, i.e provide adequate and appropriate risk assessments and Method Statements for the proposed works. See Section 12. On completion of works the contractor shall submit a current and valid certificate complying with the requirements of the current edition of the Requirements for Electrical Installations BS 7671: The format of the certification shall be either NICEIC or ECA. Certification is to be submitted to the Universitys Electrical Design Engineer for approval.

1.2.1.3 Calculations

Submissions for new sub-mains shall include the following as a minimum :

Load to be connected in kw. Earth fault loop impedance Zs. Type of cable to be used. Single or Three phase supply. Installation reference method Table 4A1 BS 7671.



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Circuit protection proposed. Anticipated volt drop. Size of cpc and earthing arrangement.

The above information will demonstrate that the consultant/designer has made reasonable efforts to establish the current demands on the electrical infrastructure prior to any proposal to add additional load. Following the completion of the installation this information will be checked against the original submission. On completion of works the contractor shall submit a current and valid certificate complying with the requirements of the current edition of the Requirements for Electrical Installations BS 7671: The format of the certification shall be either NICEIC or ECA. Certification is to be submitted to the Universitys Electrical Design Engineer for approval.

1.2.1.4 Cable

Generally power cables shall be LSF or LSHF ( Low Smoke Halogen Free ) and be BASEC ( British Approvals Service for Cables ) approved. Different services will need to comply with the relevant British Standard i.e., Automatic Fire Detection Systems BS 5839-1 All cables will be delivered to site with each coil having its seal intact and bearing the name of the manufacturer, classification, size, description of cable, length and grade. Cables in conduit or trunking: Minimum size of conductor shall be 1.5mm copper , coloured throughout the whole length in accordance with the I.E.E. regulations. PVC insulation 450/750 voltgrade, to BS 6004. Cables having insulation of butyl rubber to BS 6007, silicone rubber to BS 6007 and other heat resistant cabling to the appropriate BS Standard fit for purpose. Flexible cables: Flexible cables shall not be installed with conductor size smaller than 0.75mm and be rated at 300/500v unless specified. Cabling to many of the Universitys systems will be via Standard approved cables as detailed above. There will however be some systems that require more resilient supply cables such as the Fire detection system and Disabled Refuge systems amongst others. Listing all types of service and cables is not the purpose of this document. The important thing to remember is that during



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the design this must be established in collaboration with the Project Managers to make sure the correct cabling is installed. Listed below is a indication of the number of different services in operation at the university. This list is not exhaustive and research areas will have other special requirements:

High Voltage network. Low voltage distribution cables. Uninterruptible Power Supplies UPS. Generators. Building Management System BMS. CCTV. Access Control system. Intruder Alarm System. Fire alarm. Disabled Refuge systems. Disabled toilet communication system. Intercom systems. Induction loop systems. Electrical metering systems. Exterior lighting cables.

1.2.1.5 Supports & Fixings

Where cables are not directly supported by the use of cable cleats cable tray, a basket or ladder conforming to BS 61537 shall be utilised. These type of cable support system should be selected to carry the weight of the installed cables and where routed outside should have a protective cover to protect from the effects of UV from sun light. Cable support systems shall be manufactured from mild steel and be galvanised to reduce corrosion. Cables shall be securely fixed in place utilising either plastic or metal ties. Clamps may be required to prevent movement on larger cables in the event of short circuits. Cable routed in ceiling voids, risers and along corridors will need adequate support and fixing. Contractors found to be laying cables across suspended ceiling without containment or support will be made to correct the defective work and risk being removed from the approved contractors register. Cables supporting life protection systems such as fire alarms, disabled refuge systems and intercom systems will need to conform to enhanced fixing requirements.

1.2.1.6 Jointing

Jointing of cables will only be permitted when there is no other economic option and will not be tolerated on new installations.



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On completion of works the contractor shall submit a current and valid certificate complying with the requirements of the current edition of the Requirements for Electrical Installations BS 7671: The format of the certification shall be either NICEIC or ECA. Certification is to be submitted to the Universitys Electrical Design Engineer for approval. NOTE: No T jointing is permitted in any service cable On small duty cabling jointing will be by way of: a) Crimped compression joints utilising insulated lugs covered with heat shrink to prevent contact with live conductors. Alternatively; b) Suitably sized terminal box incorporating din rail mounted insulated through joints. The terminals and cable shall be numbered should disconnection be required in the future for testing purposes. On larger duty Low Voltage cables: a) Purpose made through jointing systems, suitable for underground, filled with cold pouring resin compounds shall be used. These joints shall be made following the manufacturers recommendations and comply with the appropriate BS Standard. c) Suitably sized and adequately fixed metal enclosure provided with din rail mounted and insulated terminals. Alternatively the connection can be via crimped and shrouded jointing.

1.2.1.7 Protection Settings

The design of any new service or circuit shall as part of the feasibility process must allow for discrimination with other devices connected either upstream or downstream of the new load/circuit. Installations incorporating interlocks and Moulded Case Circuit Bracers shall have the trip settings: (examples based on Schneider MCCBs) Micro logic 2.0 and 5.0 Ir long time threshold and tripping delay Isd short time pick up and tripping delay tr



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Tsd Ns 100 250A Ir over load protection threshold Im short circuit protection pick up labelled on the outside of the cubicle door to enable the information to be read without isolating the panel or circuit when required. This information should also be documented in the O&M manual and any circuit charts provided.

1.2.1.8 Connections to BMS See Section 4.2 in Section 4. 1.2.1.9 Labelling

Labels shall be provided on all items of equipment with a reference indicating the distribution board and way servicing the equipment. Labels shall be mounted on fixed portions of equipment and not on a withdrawable or interchangeable section. White Traffolyte material shall be used for labels, suitably sized with black lettering for general information and red lettering for warning labels. Labels shall be fixed to equipment using brass nuts and bolts securely fastened and clearly visible when facing apparatus. Bonding conductors shall be labelled at the main earth terminal bar and labelled SAFETY ELECTRICAL CONNECTION DO NOT REMOVE. Luminaire switches and socket outlets shall be labelled indicating the distribution board and way serviced by. This applies to all switches and all socket outlets installed. Dymo tape labelling shall be used for labelling accessories using black lettering on a clear backing. A common sense approach should be taken when positioning the label on to the switch or socket outlet. Radial circuits and sub-mains cabling shall have both ends of the cable run clearly identified by the use of cable identification tags securely strapped utilising nylon cable tie or equivalent. Identification tags shall be installed in a clearly visible location at each end of the supply cable.



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Hand written information is not acceptable and contractors should refrain from this practice.

1.2.1.10 Earthing

Relevant British Standards are as follows: BS 7430: 1998 Code of practice for earthing. BS EN 62305 series of standards on Protection against Lightning BS 7671: 2001 Requirements for Electrical Installations I.E.E. wiring regulations sixteenth edition The earthing system shall be in accordance with I.E.E. Requirements for Electrical Installations and comprise a separate neutral and protective conductor throughout. The main equipotential bonding conductor shall connect to the main earthing terminal, all incoming main metallic piped services and lightning protection systems. The metallic sheath of telecommunication systems is to be similarly bonded only with the permission of the operator. The extraneous conductive parts of all other separate services particular to the building also to be connected to the main earthing terminal: including heating pipes, air conditioning, medical gases, compressed air and vacuum systems and exposed metallic parts of the building fabric including metallic ceiling grids. Where necessary extraneous conductive parts of exposed metalwork shall be connected to circuit protective earth conductors by local supplementary bonding to maintain an equipotential zone. Earthing of data and telecommunications can give rise to higher than normal currents within the protective conductor and these specialist areas are covered in more depth in section 607 of IEE wiring regulations. Contractors should be aware of these areas when installing services to IT areas and satisfy the requirements of the regulations in full. The University has two main IT areas where a concentration of equipment reclassifies these areas as special locations and as such requires earthing techniques over and above that described above. Working within these areas will require additional measures and these should be discussed with the site Electrical Design Engineer.

1.2.1.11 Metering



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With new legislation coming into force in 2008 metering of supplies other than the main feed to a building will become more common. Any new meters proposed shall have a pulsed output to facilitate connection to the Universitys Trend Building Management System. See Section 4.2 in Section 4. Metering shall be capable of displaying as a minimum:

Voltage. Current. Frequency. Active, reactive & apparent power. Power factor. Power quality measurements. Data recording. Communication RS 485. Modbus protocol.

Site Standard electrical equipment is Merlin Gerin Power Meter Series 800 series. www.schneider-electric.com Contractors shall make due allowance for all interconnection necessary in connecting new metering onto the existing BMS.

1.2.1.12 Record Drawings

On completion of all projects where existing services are altered or modified the contractor shall be responsible for updating drawings showing new service routes, sizes of cables, reference labelling etc. When adjustments are made to services such as fire alarm systems the contractor shall be responsible for supplying new zone charts to fixing them in place.

As installed drawings shall be provided detailing all relevant information in the format detailed in the Universitys AutoCAD Standards. See Section 18.

1.2.1.13 Permits

The University operates a Permit to Work scheme when working on or around electrical systems. In addition to the Electrical Permit system it may be necessary to obtain other Permits to complete a project such as Confined Space, Hot Works, Roof Access etc. Before a Permit can be issued the



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contractor/consultant must submit risk assessments and Method Statements relevant to the job/survey to be carried out. In general an electrical Permit to Work will be required when:

Isolating a sub-main from a Low Voltage switch room. Working within a Low Voltage switch room. Isolating a distribution board. Access into any High Voltage switch room. Working on the High Voltage network.

Minor adjustments to electrical systems where double pole isolation is existing will generally not require a Permit to work. The contractor must still provide the appropriate risk assessments and Method Statements to the Project Administrator prior to any work commencing. The issue of a University Permit to Work does not remove any obligations under the Health & Safety at Work Act 1974 and regulations pertinent to the Electricity at Work Regulations 1989 that are placed upon the contractor. In addition to the Universitys Estates Permits to work additional Permits may be required when working in laboratories. This will need to be evaluated by the Project Administrator before work commences. Should a contractor or consultant be observed in practices likely to endanger themselves or others they will be stopped immediately and asked to attend an interview to discuss their conduct. This may ultimately result in the removal from the Universitys register.

See Section 12.9 in Section 12 See Section 12.7 in Section 12

1.2.1.14 Inspection & Testing

Periodic Inspection & Testing Following a periodic inspection, a periodic inspection report must be issued and should include the following:

The extent of the installation covered by the report. Agreed limitations of the inspection. The purpose for which the report has been requested (following fire or flood, licensing application or at the end of a recommended period). Observations and recommendations should be

categorised using the code numbering system : (1) Requires urgent attention.



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(2) Requires improvement. (3) Requires further investigation. (4) Does not comply with BS 7671.

A summary of the inspection detailing the condition of the installation with regard to safety.

A schedule of inspection and test results. The format of certification shall be either NICEIC or ECA: National InspectionCouncil for Electrical Installation Contracting. Electrical Contractors Association. Following completion of a new installation On completion of works the contractor shall submit a current and valid certificate complying with the requirements of the current edition of the Requirements for Electrical Installations BS 7671. The procedure shall be to visually inspect the installation and follow the order of test as listed in Guidance note 3 BS 7671. The contractor shall notify the client of the test date giving two clear working days to allow the test to be witnessed. Should any part of the installation fail, a re-test of the entire installation shall be carried out following corrective action. Test instruments shall be calibrated and all test leads shall be fused and fit for purpose.

1.2.2 Harmonic Filtering 1.2.2.1 General Description

What are harmonics and what cause harmonics?

Harmonics are currents or voltages with frequencies that are integer multiples of the fundamental power frequency being 50Hz. For example, if the fundamental power frequency is 50 Hz, then the 2nd harmonic is 100 Hz, the 3rd is 150 Hz, etc. In modern test equipment today harmonics can be measured up to the 63rd harmonic. When harmonic frequencies are prevalent, electrical power panels and transformers become mechanically resonant to the magnetic fields generated by higher frequency harmonics. When this happens, the power panel or transformer vibrates and emits a buzzing sound for the different harmonic frequencies. Harmonic frequencies from the 3rd to the 25th are the most common range of frequencies measured in electrical distribution systems.



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Additionally, harmonics are caused by and are the by-product of modern electronic equipment such as personal computers, laser printers, fax machines, telephone systems, stereos, radios, TVs, adjustable speed drives and variable frequency drives, battery chargers, UPS, and any other equipment powered by switched-mode power supply (SMPS) equipment.

Electronic SMPS equipment is also referred to as non-linear loads. This type of non-linear loads or SMPS equipment generates the very harmonics theyre sensitive to and that originate right within your building or facility. SMPS equipment typically forms a large portion of the electrical non-linear load in most electrical distribution systems. There are basically two types of non-linear loads: single-phase and three-phase. Single-phase, non-linear loads are prevalent in modern office buildings while three-phase non-linear loads are widespread in factories and industrial plants.

In todays environment, all computer systems use SMPS that convert AC voltage to regulated low voltage DC for internal electronics. These non-linear power supplies draw current in high amplitude short pulses. These current pulses create significant distortion in the electrical current and voltage wave shape. This is referred to as a harmonic distortion and is measured in Total Harmonic Distortion (THD). The distortion travels back into the power source and can effect other equipment connected to the same source.

What problems do harmonics create?

In an electrical distribution system harmonics create:

1. large load currents in the neutral wires of a 3 phase system. Theoretically the neutral current can be up to the sum of all 3 phases therefore causing overheating of the neutral wires. Since only the phase wires are protected by circuit breakers of fuses, this can result in a potential fire hazard, 2. overheating of electrical supply transformers which shortens the life of a transformer and will eventually destroy it. When a transformer fails, the cost of lost productivity during the emergency repair far exceeds the replacement cost of the transformer itself, 3. poor power factor conditions with a power factor less than 0.9., 4. resonance that produces over-current surges (this resulting in destroyed capacitors and their fuses and damaged surge suppressors which will cause an electrical system shutdown) and 5. false tripping of circuit breakers.

How do harmonics affect my site or facility?



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These problems affect the entire site or facility in a number of different ways:

1. Voltage distortion and voltage drop cause the equipment connected to the circuit to draw more current to maintain the power rating (watts) of the unit. The bigger the current draw from the unit, the more it produces excess heat within the unit that was not factored for by its original design. In turn, the excessive heat causes premature component level failures within the unit. Additionally, you will experience computers locking up and other operational malfunctions that are unexplainable. The excessive heat produced can directly contribute to downtime. Therefore, downtime is identified as any event that incurs or contributes to lost productivity, lost revenues, lost savings, and more importantly lost time. 2. Telecommunications cabling is commonly run right next to power cables. If harmonics are above normal tolerances (more than 5% THD) as outlined in G5/4 then high frequency harmonics can be induced into phone lines and data cabling. The end result is noisy phone lines and unexplained data loss or data corruption.

How can we wire electrical distribution systems for harmonics?

These are recommended ways to wire for the harmful effects that harmonics cause. However, these recommendations only keep the electrical distribution systems safe. These wiring recommendations do not eliminate or cancel high levels of harmonics.

1. Use double-size neutral wires or separate neutrals for each phase. 2. Specify a separate full-size insulated earth conductor rather than relying on the conduit alone as a return ground path.

How can we treat harmonics?

In order to ensure the highest "Power Quality" for buildings it is necessary to treat harmonics. Harmonic treatment can be performed by two methods: filtering or cancellation. A harmonic filter consists of a capacitor bank and an induction coil. The filter is designed or tuned to the predetermined non-linear load and to filter a predetermined harmonic frequency range. Usually this frequency range only accounts for one harmonic frequency. This application is mostly used when specified for a UPS or variable frequency drive motor in a manufacturing plant.

Harmonic cancellation is performed with harmonic canceling transformers also known as phase-shifting transformers. A harmonic canceling transformer is a relatively new power quality



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product for mitigating harmonic problems in electrical distribution systems. This type of transformer has patented built-in electromagnetics technology designed to remove high neutral current and the most harmful harmonics from the 3rd through 21st. The technique used in these transformers is call "low zero phase sequencing and phase shifting". These transformers can be used to treat existing harmonics in buildings. This same application can be designed into new construction to prevent future harmonics problems.

1.2.2.2 Surveys

It is important when considering harmonic filtering, as a means of improving power quality, to undertake a detailed study of the electrical installation over a minimum period of seven days.

The installation of data logging equipment may require exterior paneling to be removed to facilitate ct clamps to be installed. Should this be necessary then an electrical Permit will be required along with risk assessments and Method Statements.

See Section 12.9 in Section 12

This will help to establish the correct type of unit that will be required such as Tuned or Active filtering. A minimum of one weeks data should be logged in order to make an accurate evaluation.

1.2.2.3 Connection Arrangements

For loads in excess of 3kw the following shall apply Prior to any connection/isolation the following information shall be submitted to the Project Manager. Information required prior to a connection being authorised:

Accurate evaluation of anticipated load. The date when connection is required. Single or three phase load. Type of load to be connected. The location of the new load. Origin of service distribution board load to be taken from.

It is important to consider the effect the additional loads will have on the existing electrical infrastructure. Consultants/designers must undertake and submit valid feasibility studies to support their recommendations when introducing additional electrical loads. These should be submitted and discussed with the Universitys Electrical Engineer prior to any work commencing on site. If this process is omitted and subsequent problems



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arise, any additional cost in rectifying the situation will rest firmly with the consultants/designers of the installation. Isolations to facilitate connection of an electrical load need careful planning as a large proportion of the building are research orientated. This places additional constraints on contractors when isolations are required. Typically this type of interruption will be arranged over weekend periods or out of normal working hours to minimise disruption to users bases on the area where the connection is to be made. Consideration must also be given to other services which use an electrical supply to maintain services such as:

CCTV. Site wide IT networks. Fume cupboard extract. Localised IT Network. Fire alarm panels. Intruder alarm panels. Wi Fi IT systems. University BMS.

This list is not exhaustive but designed to give an idea of the disruption that must be avoided when isolating sub-mains to buildings or distribution boards. The Estates department have two account managers who can help when dealing with such matters.

Trevor Smith. Corinne Ashwell.

If contact is made at an early stage a co-ordinated approach can be made when isolations are required. The UEA operate a Permit to Work system for electrical works and contractors must comply with this without fail. See Section 12.9 in Section 12.

Any persons undertaking this type of work must be competent when working or operating low voltage electrical equipment and comply with the Universitys Health & Safety rules i.e., provide adequate and appropriate risk assessments and Method Statements for the proposed works. See Section 12 On completion of works the contractor shall submit a current and valid certificate complying with the requirements of the current edition of the Requirements for Electrical Installations BS 7671: The format of the certification shall be either NICEIC or ECA. Certification to be submitted to the Universitys Electrical Design Engineer for approval.



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1.2.2.4 Cable

Generally power cables shall be LSF or LSHF ( Low Smoke Halogen Free ) and be BASEC ( British Approvals Service for Cables ) approved. Different services will need to comply with the relevant British Standard i.e., Automatic Fire Detection Systems BS 5839-1. All cables will be delivered to site with each coil having its seal intact and bearing the name of the manufacturer, classification, size, description of cable, length and grade.

1.2.2.5 Containment System Cables in conduit or trunking: Minimum size of conductor shall be 1.5mm copper, coloured throughout the whole length in accordance with the I.E.E. regulations. PVC insulation 450/750 voltgrade, to BS 6004. Cables having insulation of butyl rubber to BS 6007, silicone rubber to BS 6007 and other heat resistant cabling to the appropriate BS Standard fit for purpose. Flexible cables: Flexible cables shall not be installed with conductor size smaller than 0.75mm and be rated at 300/500v unless specified. Cabling to many of the Universitys systems will be via Standard approved cables as detailed above. There will, however, be some systems that require more resilient supply cables such as the Fire detection system and Disabled Refuge systems amongst others. Listing all types of service and cables is not the purpose of this document. The important thing to remember is that during the design this must be established in collaboration with the Project Managers to make sure the correct cabling is installed. Listed below is an indication of the number of different services in operation at the University. This list is not exhaustive and research areas will have other special requirements:

High Voltage network. Low voltage distribution cables. Uninterruptible Power Supplies UPS. Generators. Building Management System BMS. CCTV. Access Control system. Intruder Alarm system. Fire alarm. Disabled Refuge systems.



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Disabled toilet communication system. Intercom systems. Induction loop systems. Electrical metering systems. Exterior lighting cables.

1.2.2.6 Supports & Fixings

Where cables are not directly supported by the use of cable cleats, a cable tray, basket or ladder conforming to BS 61537 shall be utilised. This type of cable support system should be selected to carry the weight of the installed cables and where routed outside should have a protective cover to protect from the effects of UV from sun light. Cable support systems shall be manufactured from mild steel and be galvanised to reduce corrosion. Cables shall be securely fixed in place utilising either plastic or metal ties. Clamps may be required to prevent movement on larger cables in the event of short circuits. Cable routed in ceiling voids, risers and along corridors will need adequate support and fixing. Contractors found to be laying cables across suspended ceiling without containment or support will be made to correct the defective work and risk being removed from the approved contractors register. Cables supporting life protection systems such as fire alarms, disabled refuge systems and intercom systems will need to conform to enhanced fixing requirements.

1.2.2.7 Equipment & Locations

Following the selection of a suitable unit, the contractor/consultant will need to establish the most appropriate location in which to site the equipment. To a certain extent the location of the unit will be determined by the load producing the harmonics. Consideration should be given for access for installation and access for maintenance.

1.2.2.8 Circuit Protection

Installation shall conform to the current edition of BS 7671. A means of isolation shall be provided local to the equipment installed and be clearly labelled to identify its purpose. Circuit protection settings must allow for discrimination with other devices fed from a panel board way and verification must be carried out before the circuit is energised.

1.2.2.9 Connections to BMS

See Section 4.2 in Section 4



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1.2.2.10 Record Drawings

On completion of all projects where existing services are altered or modified the contractor shall be responsible for updating drawing showing new service routes, sizes of cables, reference labelling etc. When adjustments are made to services such as fire alarm systems the contractor shall be responsible for supplying new zone charts to fixing them in place.

As installed drawings shall be provided detailing all relevant information in the format detailed in the Universitys AutoCAD Standards. See Section 18.

1.2.2.11 Permits

The University operates a Permit to Work scheme when working on or around electrical systems. In addition to the Electrical Permit system it may be necessary to obtain other Permits to complete a project such as Confined Space, Hot Works, Roof Access etc. Before a Permit can be issued the contractor/consultant must submit risk assessments and Method Statements relevant to the job/survey to be carried out. In general an electrical Permit to Work will be required when:

Isolating a sub-main from a Low Voltage switch room. Working within a Low Voltage switch room. Isolating a distribution board. Access into any High Voltage switch room. Working on the High Voltage network.

Minor adjustments to electrical systems where double pole isolation is existing will generally not require a Permit to work. The contractor must still provide the appropriate risk assessments and Method Statements to the Project Administrator prior to any work commencing. The issue of a University Permit to Work does not remove any obligations under the Health & Safety at Work Act 1974 and regulations pertinent to the Electricity at Work Regulations 1989 that are placed upon the contractor. In addition to the Universitys Estates Permits to work additional Permits may be required when working in laboratories. This will


Estates and Buildings Division DESIGN GUIDE

1.147640!section 1 electrical services

Documents

general description

general construction

electrical services

university community

functional description

containment system

design standards

panel construction