eds 07-0020 civil requirements for new customer supplies...

Document Number: EDS 07-0020

Version: 5.0

Date: 21/07/2016

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Engineering Design Standard

EDS 07-0020

CIVIL REQUIREMENTS FOR NEW CUSTOMER SUPPLIES AND GENERATION CONNECTIONS

Network(s): EPN, LPN, SPN

Summary: This standard provides guidance on the Civil and Building services requirements for substations and switchrooms constructed by customers and developers to accommodate equipment to be installed or adopted by UK Power Networks.

Author: Uriel Arias Date: 21/07/2016

Approved By: Paul Williams Approved Date: 31/08/2016

This document forms part of the Company’s Integrated Business System and its requirements are mandatory throughout UK Power Networks. Departure from these requirements may only be taken with the written approval of the Director of Asset Management. If you have any queries about this document please contact the author or owner of the current issue.

Applicable To

UK Power Networks External

All UK Power Networks G81 Website

Asset Management Contractors

Capital Programme ICPs/IDNOs

Connections Meter Operators

HSS&TT

Network Operations

UK Power Networks Services

Other

Civil Requirements for New Customer Supplies and Generation Connections


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Date: 21/07/2016

© UK Power Networks 2016 All rights reserved 2 of 19

Revision Record

Version 5.0 Review Date 31/08/2021

Date 21/07/2016 Author Uriel Arias

Why has the document been updated: updated required after receiving construction feedback

What has changed: document updated throughout including; security rate requirements for building fabric and doors clarified; details of trench covers, door stays and floor coating introduced; Minor clarifications.

Document reviewed and review date extended


Date 11/01/2016 Author Uriel Arias

Why has the document been updated: updated required after receiving construction feedback

What has changed: Section 1: clarification on relevance of the standard for Looped and Tee’d connections. Section 2: Security doors specification updated. All associated drawings updated to allow for refinements to brickwork, ducts, pumps, trench layout and small power. Section 9 (Dependent Documents) added.

Review date extended


Date 02/02/2015 Author Mark Dunk

Why has the document been updated – Update and clarification of information

What has changed - Section 1 - Introduction updated to provide greater clarity of the use and application of this document. Section 4 updated to clarify requirement for separate rooms for Customer and UKPN equipment. Section 5.7.1 updated to clarify security rating and heavy duty doors stay requirements.

Document title amended.



Why has the document been updated: Updated to include drawing EDS 07-0020-04

What has changed: Addition of drawing EDS 07-0020-04 and references updated in document.



Original



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Contents

1 Introduction ............................................................................................................. 4

2 Scope ....................................................................................................................... 4

3 Glossary and Abbreviations ................................................................................... 5

4 General Requirements ............................................................................................ 6

4.1 Health and Safety ...................................................................................................... 6

4.2 Environment .............................................................................................................. 6

4.3 Security ..................................................................................................................... 6

4.4 Legislation ................................................................................................................. 6

4.5 Flood Risk ................................................................................................................. 7

4.6 Fire Risk .................................................................................................................... 7

5 External Requirements ........................................................................................... 8

5.1 Location ..................................................................................................................... 8

5.2 Access to Site ............................................................................................................ 8

5.3 Underground Services ............................................................................................... 9

5.4 Drainage .................................................................................................................... 9

5.5 Landscape around the Switch House ...................................................................... 10

5.6 Earthing ................................................................................................................... 10

6 Building Requirements ......................................................................................... 11

6.1 Switchroom ............................................................................................................. 11

6.2 Building Base and Cable Trench ............................................................................. 11

6.3 Building Services ..................................................................................................... 12

7 Elements and Materials ......................................................................................... 13

7.1 Foundations ............................................................................................................ 13

7.2 Walls ....................................................................................................................... 13

7.3 Roof ........................................................................................................................ 13

7.4 Ducts and Sealing System ....................................................................................... 13

7.5 Finishes ................................................................................................................... 14

7.6 Doors ...................................................................................................................... 14

7.7 Vents and Overpressure .......................................................................................... 15

8 List of Drawings .................................................................................................... 16

9 References ............................................................................................................. 17

9.1 UK Power Networks Documents.............................................................................. 17

9.2 External Standards .................................................................................................. 17

10 Dependent Documents.......................................................................................... 18



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1 Introduction

The purpose of this document and the associated drawings is to provide guidance for civil and building services requirements to internal and external designers, ICPs, customers and contractors who need to provide accommodation for UK Power Networks incoming supply and related auxiliary equipment for customer electrical supplies at voltages from 6.6kV to 33kV.

The equipment footprint and the support designs shown in the standard drawings have been produced for use with specific equipment types. The designs may be modified or adapted where necessary to suit switchgear of other types and manufacturer, provided that the switchgear to be installed is of a type approved for use by UK Power Networks. All works designed for adoption by UK Power Networks, under the provisions of ENA ER G81 ‘Framework for Competition in Connections’ will need to have written approval from UK Power Networks representative for the project prior to commencement of construction.

Developers, local authorities and other stakeholders’ specific requirements may dictate deviations from the generic design proposed in this document; in all cases, it is essential that the guidance outlined in this document is properly embedded in the final design. In reading this document, specific reference must be made to EDS 08-0051 ‘Customer Supplies 6.6kV-33kV Notes of Guidance of New Demand and Generation Connections’.

2 Scope

This standard defines to the process to be followed for the construction of buildings and housings accommodating:

Supply-side equipment required for customer demand;

Generation connections at voltages between 6.6kV and 33kV teed to networks owned by UK Power Networks.

Refer to EDS 07-0105 ‘Grid and Primary Civil Design Standards’ suite of documents for projects where the connection agreement specifies UK Power Networks are to adopt and/or are responsible for the maintenance/repair of the building and structural assets or when a ‘looped’ network connection is required.



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3 Glossary and Abbreviations

Term Definition

AONB Areas of Outstanding Natural Beauty

CDM regulations Construction (Design and Management) Regulations

EA Environment Agency

GRP Glass Reinforced Plastic

ICP Independent Connections Provider

Looped connection Connections where the switchgear is in “the middle of the network”, so

anything that affects the switchgear will not only have an impact on the

immediate customer but to the thousands of customers directly or

indirectly connected to that network

RTU Remote Terminal Unit

SCADA Supervisory Control And Data Acquisition

SSSI Sites of Special Scientific Interest

Teed Connection Connections where the switchgear is ‘at the end of the network”, so

anything that affects the switchgear will have an impact on the immediate

customer only.

U Value Measure of Thermal Conductivity

UK Power Networks UK Power Networks (Operations) Ltd consists of three electricity

distribution networks:

Eastern Power Networks plc (EPN).

London Power Network plc (LPN).

South Eastern Power Networks plc (SPN).



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4 General Requirements

4.1 Health and Safety

In accordance with the Construction (Design and Management) Regulations, safe construction, access, maintenance, operation and demolition of the structure in addition to the installation and removal/replacement of all plant shall be considered during the design process. Furthermore maintenance requirements should be planned to ensure that future building upkeep will be minimal.

A site specific risk assessment must be completed for all elements of the substation. This should be included as part of the CDM H&S documentation to be retained on site by the developer. When the project is complete the Substation H&S folder must be handed over with all risks updated.

4.2 Environment

UK Power Networks is committed to protect the natural and built environment, including wildlife, water and historic features. It is the Developer’s responsibility, as part of the design process to assess environmental issues and to consider any potential impact to historic structures or ecologically sensitive areas, including Scheduled Ancient Monuments, Sites of Special Scientific Interest (SSSI), Areas of Outstanding Natural Beauty (AONB), Nature Reserves and Protected Areas for Birds. The Company reserves the right to request any proof of approval applicable from third parties, for instance from the Environment Agency, authorizing the works where the substation will be located.

4.3 Security

Site security is imperative to safeguard the building and its equipment from damages, theft, and vandalism; also to safeguard against unauthorised access to high voltage equipment. In order to ensure that adequate security is planned for and designed in, it is important to liaise with UK Power Networks Security representatives early in the design of the substation, so to assess the degree and specification of security equipment required after the energization and handover of the assets back to UK Power Networks. Subject to site confirmation, SR2 is the minimum Security Rate expected for switch house’s fabric and elements (e.g. doors, overpressure vents, walls etc.).

4.4 Legislation

The substation design must comply with the following:

Construction (Design Management) regulations;

Health, Safety and Environmental legislation;

European and British standards;

The ‘Building Regulations’, Part L2A

The ‘Town and Country Planning Act’

The above list is given as a reference set of documents and is not meant to be a comprehensive list. Other pieces of legislation or Standards may apply depending on the site conditions.



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4.5 Flood Risk

The National Planning Policy Framework (NPPF) and the online resource called ‘Planning Practice Guidance – Flood Risk and Coastal Change’ are the official references that regulate the assessment of flood risks and the appropriate mitigation planning process. The NPPF sets tests to protect people and property from flooding which in principle are designed to discourage the development of land in flood zones. If found that the proposed site is likely to be affected by flooding issues, ideally an alternative site should be sourced. In real terms, however, this cannot always be achieved and it therefore becomes essential that flood mitigation measures are put in place.

The floor level of the switchroom should be constructed at a level of 300mm above the 1 in 100 river flood level or the 1 in 200 year tidal flood level, whichever is higher. A flood risk assessment shall be carried out, and substations should not normally be constructed in areas which may be subject to flooding with a greater risk than 1 in 100 year river flood level or 1 in 200 year tidal flood level. Where there is no other option but to construct in an area known to have a higher flood risk than that quoted above, the guidelines in UK Power Networks document EDS 07-0106 ‘Substation Flood Protection’ shall be followed.

4.6 Fire Risk

Substation buildings must be designed to prevent the propagation of fire, in particular from an electrical failure from internal switchgear or from power cable faults. For building designs (e.g. GRP housings) where the mounting of equipment to the walls makes use of ply back boards, the adverse effects of these to the fire rating should be considered.

It is important that means of escape are allowed to exit from the building; a maximum 12m travel distance to the nearest door affording an escape route must be incorporated. Further means of escape shall be provided where site-specific risk assessment dictates so or where otherwise deemed as necessary by UK Power Networks for the safe operation of the substation. Escape routes shall give access to a safe external area or to a protected zone giving access to a safe external area. Escape route passages shall have a minimum clearance width of 750mm and all doors being part of the escape route must have a minimum clear opening of 750mm wide by 2000mm high. Pedestrian safety barriers may be necessary when the escape route leads to vehicular traffic route. These barriers may need considerations for temporary removal to facilitate access to site of maintenance teams or the delivery of equipment. The switch house shall be included in the fire risk-assessment for the general project. The minimum acceptable fire resistance for the building/enclosure will be of one hour, but more may be required subject to the fire risk assessment; the fire rate extent must include below floor trenches and ducts passing between rooms (if any), such that spread of fire is prevented. For a switch house within 4m of occupied buildings, the fire rate must be four hours. Fixed or portable fire-extinguishing equipment shall not be fitted in switch houses. The switch house Fire Risk Assessment and the Fire Plan are to be developed in conjunction with the local Fire Brigade representative wherever possible or through the use of a competent, specialist fire safety contractor.

In the event that the Local Fire Authority requires the fitting of an automatic fire suppression system to the building, where part of the system is fitted in the UK Power Networks switchroom, it shall be:

Suitable for high voltage electrical hazards;

Fitted with external lockable isolation adjacent to the switchroom entry door;

Designed by a fire suppression system specialist employed by the customer;

Approved by the UK Power Networks Designer.



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5 External Requirements

5.1 Location

The building or housing for UK Power Networks owned or adopted equipment, wherever possible, shall be a free-standing structure constructed at a boundary location. Semi-detached buildings attached to a main structure or customer’s switchroom, but not integrated into the main building, may also be acceptable provided that access is not restricted.

If no other alternative is available, e.g. due to space or planning restrictions, a switchroom at ground level, which is integrated into the larger building, may possibly be used providing that there is adequate and unrestricted access and is subject to agreement by the UK Power Networks project representative.

Locations above or below ground level shall not normally be considered, regardless of building configuration, for reasons of maintaining safety and control over operation, UK Power Networks and Customer/Developer equipment must be located in separate rooms with their own separate access. No customer owned equipment shall be installed in the chamber used to accommodate equipment owned by, or to be adopted by, UK Power Networks with the exception of the cables connecting to the customer’s installation.

The building should be located externally to the solar/wind generation compound and subject to the site layout, served via a dedicated access.

5.2 Access to Site

The switch house shall be accessible to UK Power Networks staff at all times from the public highway and be fitted with standard locks (Locken or current compatible) which will be supplied and installed by UK Power Networks, when the supply is energised. Where the switch house is accessed via a gate in an external boundary, an approved proprietary dual locking system must be installed (e.g. Tayhope or similar approved). Coded access is not permitted. It is essential that all designs allow unrestricted access for equipment and UK Power Networks’ or their agents’ personnel.

Once commissioned, the switch house shall only be accessible to persons who hold the necessary authorisation under UK Power Networks Distribution Safety Rules. This will not normally include the customer’s staff.

Designs shall cater for equipment delivery using a Large Goods Vehicle with a lorry mounted crane, and have a minimum width of 3.5m and a clear height of 4m with an unloading area directly outside the switch house double doors.

The access shall be designed to accept a minimum axle weight of 11 tonnes and an adequate turning bay if access is possible from one direction only. Access to replace faulty equipment, should the need arise, must be maintained at all times. Refer to EDS 07-0021 ‘Substation Temporary Access Road’ for details of the unmade access road specifications for distribution generation projects.



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5.3 Underground Services

Due to the extent of services located within a site, like drainage, cables, earth mat, building services and multicores, it is imperative that the setting out of all underground services are recorded as installed.

Where possible, services shall be routed away from areas that may be used for heavy equipment delivery. If this is not possible, suitable protection shall be provided. Cable routes shall be located to avoid the undermining of the sub-base to the site roads when excavated.

The substation design must be such that sprinkler systems, water, gas, drainage or third party service cables, pipes and heating/ventilation ducts do not cross through or below the switch house.

5.4 Drainage

Substations shall be adequately drained for the anticipated normal environment with precautions to prevent ingress of moisture. External ground/access road levels shall be designed such that there is no detrimental build-up of surface water in the proximity of the enclosure. Rain water from the switch house roof shall be collected into its own system and directed into a soakaway as far removed from the switch house (minimum 5m from any building) if the ground infiltration test allows for this. Alternatively, direct connection into nearby ditch watercourse or shallow swale should be implemented. A system of land drainage may be installed adjacent to the building at an invert level below cable entry level and connected into the site surface water drainage system. Surface water drainage shall include the roof and in some cases the road surface water. The substation drainage design must ensure that the pipework detailed is properly sized and levelled for flow rates with the pipes running un-surcharged at self-cleaning non-scouring velocities. The surface water drainage systems must be designed for storm conditions to a return period of 100 years or greater, subject to site conditions. As it is not always possible to seal cable entry ducts such that they are 100% water-tight and seepage can cause pooling or standing water which can contribute to the corrosion of contacts within the switchgear leading to operational malfunction, it is necessary to install a pump to remove this water from the cable trench; this should be a 230v, stainless steel frame pump with float switch activated with a capacity to discharge 110 litres per minute at 2-3 metre head.



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5.5 Landscape around the Switch House

A 1200mm wide pedestrian paved footpath should be laid from the roadway to the main doors of the switch house. A 600mm wide pedestrian footpath should be also laid between all doors, including the metering room.

Areas to receive 600x600x50mm precast paving slabs to be on a combined minimum 125mm overall thickness of sand-cement bed on compacted imported DTp Type 1 clean graded stone sub-base.

Reinforced concrete landing slabs to be cast in-situ to all doors; front double door slab to be on minimum of 300mm compacted DTp type 1. All slabs to suit with of door-sets plus width for hand rails as necessary; hand rails should not obstruct the escape route.

5.6 Earthing

EDS 06-0019 ‘Customer EHV and HV Connections (including Generation) Earthing Design and Construction Guidelines’ provides guidance on the design and construction of earthing systems for customer demand and generation connections.

The earthing system for a 33kV substation shall be designed in accordance with EDS 06-0013 ‘Grid and Primary Substation Earthing Design’ and shall be constructed in accordance with ECS 06-0022 ‘Grid and Primary Earthing Constuction’.

The earthing system for a 20kV, 11kV or 6.6kV substation shall be designed in accordance with EDS 06-0014 ‘Secondary Substation Earthing Design’ and shall be constructed in accordance with ECS 06-0023 ‘Secondary Distribution Network Earthing Construction Standard’.

All substation earthing designs shall be approved by UK Power Networks before construction. The customer shall provide a comprehensive earthing report with supporting calculations and associated earthing drawings to enable the design to be assessed. Refer to EDS 06-0019 for further information.

All earthing passing though ducts that require sealing to be solid, sheathed, and not bare stranded.



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6 Building Requirements

6.1 Switchroom

All UK Power Network’s buildings or housings shall provide a robust, window-less, vandal-resistant and stable environment for the switchgear and ensure that equipment is not damaged by any environmental cause such as condensation, dust or other pollutants. There must be sufficient space for operator safety and all necessary auxiliary and operational equipment, including steps, where these are required to access operational equipment.

All designs will need to take account of the switchgear manufacturer’s requirements for overpressure venting and have a minimum floor to ceiling height of 3150mm, this may need to be increased depending upon the switchgear manufacturer’s requirements.

The straightness tolerance of the Unistrut foundation channels, which are provided by the customer, will be in the range of 1mm over a metre of channel length. The switchgear manufacturer’s installation instructions shall be consulted to confirm the required accuracy tolerance for fixing the switchgear.

6.2 Building Base and Cable Trench

The cable trench for substations with below ground cable entries shall be reinforced concrete of sufficient density and water tightness to prevent dampness on the internal surfaces. The depth of the cable trench will depend on the bending radius of the cables used, typically the depth of the cable trench falls in the range between 1350 to 1500mm; however it may be necessary to increase it to suit other bending radius or cable connection to switchgear.

Safe access provisions into the cable trench must be assessed for trench depths greater than 380mm, for instance inclusion of hand rail or access steps; access to the underside of the gear should be such that awkward working spaces are prevented when live cables are in place.

The switchgear cable entry arrangements for the main and auxiliary cables need careful consideration to permit safe and practicable termination of all cables.

The requirement for external duct entries into the switchroom shall ensure that adequate provision is made for all incoming and outgoing circuits including control and communications cables and earth connections. The cable access arrangements shall allow a minimum bending radius of 1m for all 6.6, 11 and 33kV cables.

Trench covers to be anti-slip top solid GRP, flame retardant on galvanised mild still frame and to be sized to be easily lifted, without binding against adjacent covers and individually located. The width of the each GRP board shall not exceed the width of the single switchgear panel in front of it (generally 500mm) and the individual weight of the GRP panel shall be limited to 18Kg. All trench covers shall have a 120x40mm hand-hole at each end.

All ICP or customer’s drawings will need to be approved in writing by the UK Power Networks designer before any construction work is commenced.



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6.3 Building Services

Switchrooms designed for the installation of indoor extensible switchgear at 33kV, 20kV, 11kV, or 6.6kV or its controlling equipment, must have a controlled environment designed to prevent condensation forming in or around the equipment. In practice this will require the installation of heating and de-humidification with automatic control systems and alarm systems to be linked to the UK Power Networks SCADA system.

Switchrooms or housings used for outdoor ring main unit type equipment will not require heating or de-humidification equipment.

It should be noted that UK Power Networks will not adopt metal clad 6.6kV to 33kV distribution substation equipment installed in an outdoor environment.

The HV/EHV Switchgear and the equipment detailed in Appendices A1 or A2 will be required within the switch room; it is important to make the necessary provisions of wall/floor space for the final equipment schedule agreed by UK Power Networks and by the switchgear manufacturer.

Suitable external provisions will need to be incorporated in the design to house metering equipment at no more than 5m away from the switch house. For standard details about Small Power, Lighting and Conduit/Trunking systems and refer to EDS 07-0119 ‘Electrical Services for Grid, Primary and Secondary Substations’.



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7 Elements and Materials

The external appearance of the building and the type of construction used shall be designed and constructed by the customer, or their appointed contractors, and will need to comply with any Local Authority Planning and Construction Regulations; all planning and building consents are to be obtained by the customer.

7.1 Foundations

The concrete base, floor slab and walls are to be constructed to the customer’s design and will be subject to UK Power Networks approval.

All concrete is to be grade C32/40 with a minimum content of 300kg/m3 of Sulphate Resisting Cement to BS12, and maximum water/cement ratio of 0.6. The maximum aggregate size is not to exceed 20mm. A Visqueen 1200 gauge membrane (or equivalent) is to be provided beneath the floor slab, laid on 25mm of sand blinding, on a minimum 150mm thick, well compacted, sub-base.

Reinforcement bar layouts are to be designed by the Structural Engineer employed by the customer. The reinforcement mesh is to be supported with proprietary chairs with a minimum cover of 50mm. The mesh is not to be trodden into the concrete surface.

7.2 Walls

For all installations at 20kV and above and for 6.6/11kV installations where indoor extensible switchgear is used, the switch house must provide a regulated indoor environment. The external walls of the building shall achieve a U value of 0.35W/m2K and, where practicable, all walls must be suitable to allow the secure fixing of wall mounted equipment and associated cabling.

The wall details are to be designed by a Structural Engineer employed by the customer, and may be subject to approval by the Local Planning Authority and/or building control. The building/housing will use typically a brick/block cavity wall system. Alternative construction types will be considered providing that the correct environment is established to ensure that the equipment installed is not damaged or put at risk in any way by environmental conditions.

7.3 Roof

The roof construction is to achieve a U value of 0.25 W/m2K. The details of roof construction are to be designed by a Structural Engineer employed by the customer, and may be subject to approval by the Local Planning Authority and/or building control.

Whichever the roof shape, the design should allow for adequate drains (including rain down pipes), seals and if necessary means to release the overpressure generation by the blast of one of the switchgear panel.

7.4 Ducts and Sealing System

All duct and cable entries to the switchroom shall be sealed after cable installation using an approved duct sealing system to prevent water ingress into the building.

It is important to choose the duct seal system according to the shape of the conductor going through the each duct. To prevent water leaking into the building, the use of bare braided conductors through ducts is not accepted. A proprietary water-resistant duct seal system should be used at cable pits and basements (e.g. CSD RISE, or similar approved).



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7.5 Finishes

Internal lining and structural surfaces shall be non-flammable material of limited combustibility such the spread of flame over their surfaces can be resisted.

With the exception of external doors, fabric finishes internal to the switchgear room shall meet the requirements of National Building Regulations for low surface spread of flame and low fire propagation index (e.g. Class O). The fire protection to steel frames shall not be fireboard that could be displaced in the event of a disruptive failure.

Concrete floors will be finished with a water base two pack epoxy coat (e.g. BS 3000SG by Remmers or similar approved).

7.6 Doors

7.6.1 General Requirements for All Doors

All doors are to be certified to minimum grade of SR2 in accordance with the latest issue of the Loss Prevention Board LPS 1175 specification. SR4 rated doors may be required where a high risk of unauthorised entry is known; In general door specifications shall be as follows:

Colour: BS 14C39 green or as required for the local colour scheme required by planning regulations;

Locking arrangements: suitable to accept Locken system or similar in use with either Europrofile or Scandinavian lock barrels -subject to UK Power Networks stock availability;

Heavy duty doors stays (HD7000 or similar approved) to hold the door open at 90 degrees during normal operational conditions of the site;

Hinges: each door leaf is to be hung on a minimum of three heavy-duty stainless steel hinges. Hinges are to incorporate 'dog bolts' or equivalent means of protection;

Security strip to the leading edge of the doors: mask the gap between the doors or between the door and frame. Door sets shall be fitted with a suitable weather seal strip;

Earthing: steel doors shall be connected in accordance with the relevant earthing standard, see Section 5.1.7;

No smoking signs: supply and fix ‘No Smoking’ sign in accordance with SI 2007/923, refer to section 13.4 in Code of Practice for no smoking signs requirement;

Finish: door to be protected with powder coat or other high performance paint finish;

Door thresholds: not to exceed 12mm;

Signage: purposed-made sacrificial plates for signage fixing are required to prevent on-site drilling on door structure, thus damaging the protecting coat.

Note that the Contractor should supply unique locks until the site is commissioned, after which the Contractor will replace with standard Operational Cylinders or Locken electronic barrels, supplied by UK Power Networks.



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7.6.2 Double Door Specific Requirements

Furniture: two dead locks with internal thumb knob stain finish (no thumb wheels). Key-ring anti-scratch escutcheons. Double panic bar with top and bottom shoot bolts. Internal and external pull handles (without lock).;

Structural opening: 3000H x 1810W [mm]; door height may vary according to the requirements of different manufacturers; a transom and hinged over-panel is to be allowed where the delivery height exceeds that of the standard opening. The door should be tall enough to accommodate the panel, transit packaging and delivery method;

Hinges should allow door leaves to open 180 degrees. Doors to be fitted with stainless steel ‘hook and staple’ or similar approved arrangement to hold the door open safely when leaves fully open.

7.6.3 Escape Door Specific Requirements

Furniture: panic bar with top and bottom shoot bolts and pull handle. No external handle or lock barrel to be fitted;

Structural opening: 2250H x 910W [mm].

Door stays: HD7000 or similar approved door restraints to holding the doors open at 90 degrees are to be fitted at the head of the door leaf.

7.6.4 Metering Room Door Specific Requirements

Furniture: mortice sashlock, with round section external lever handle and escutcheon and Europrofile/Scandinavian cylinder with internal thumb-turn to suit metering operator lock barrel;

Structural opening: 2250H x 910W [mm];

Door stays: door restraints to holding the doors open at 90 degrees are to be fitted at the head of the door leaf.

7.7 Vents and Overpressure

All designs will need to take account of the switchgear manufacturer’s requirements for overpressure venting and have a minimum floor to ceiling height of 3150mm, this may need to be increased depending on the switchgear used in the project. The overpressure vents should not undermine the wall’s Thermal Conductivity and the building security and fire rates.

For reference, SHX integral system by AFP Tech has been used by UK Power Networks (alternative manufacturer’s may be considered). In addition to the vents, a Heavy Duty Security Grille should be fitted on the outside face to maintain the building security rating. Overpressure vents must be designed as to prevent the free flow of air when in the static position.

For guidance on overpressure relief refer to the following documents:

Switch house over pressure relief system, EDS 07-0001 ‘Substation Overpressure Relief System’;

Substation overpressure and security doors, EOP 07-0029 ‘Substation Overpressure and Security Doors;

Substation overpressure, EDS 07-0111 ‘Switchroom Overpressure’.



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8 List of Drawings

A number of generic footprint drawings have been produced to assist customers and ICPs with the design of switchroom chambers. These have been produced for the indicative layout of specific types of switchgear and will need to be modified, or otherwise adapted, to accommodate other manufacturers and types, particularly with regard to fixings, supports, and switchgear main and auxiliary cable entry arrangements.

UK Power Networks drawing Number EDS 07-0102-16 may be used as the basis for housing a ring main unit at 6.6 or 11kV, with the addition of 230v electrical supplies, control cables and metering.

Drawing Number Subject

EDS 07-0020-01 33kV Metering Switch-house Using Siemens NXPLUS – Single Circuit

EDS 07-0020-02 33kV Metering Switch-house Using Siemens NXPLUS – 3 Panel Loop

EDS 07-0020-03 11kV Metering Switch-house Using Schneider Genie Evo – 3 Panel Loop

EDS 07-0020-04 Standard Brick Enclosure for Customer RMU with Metering Panel

EDS 07-0020-05 Satellite Dish Steelwork and Concrete Base Details

EDS 07-0020-05 Door Schedule for Metering Switch-house

EDS 07-0102-16 GRP Enclosure & Plinth Design for Metered RMU



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9 References

9.1 UK Power Networks Documents

EAS 06-0011 Earthing Materials

ECS 06 0022 Grid and Primary Earthing Construction

ECS 06 0023 Secondary Distribution Network Earthing Construction

EDS 06-0013 Grid and Primary Substation Earthing Design

EDS 06-0014 Secondary Substation Earthing Design

EDS 06-0017 Customer LV Installation Earthing Design

EDS 06-0019 Customer EHV and HV connections (including generation) earthing design and construction guidelines

EDS 07-0101 Security Specification for UK Power Networks Operational Sites

EDS 07-0105 Grid and Primary Standard Civil Designs

EDS 07-0106 Substation Flood Protection

EDS 07-0119 Electrical Services for Grid, Primary and Secondary Substations

EDS 08-0051 Customer Supplies between 6.6 and 33kV – Notes of Guidance for New Demand and Generation Connections

EDS 08-0109 11/6.6kV Secondary Distribution Network Design

EDS 08-0113 Guidance for the Application of ENA Engineering Recommendation G88 and G81 Inset Networks (IDNOs and other Licensed DNOs)

EDS 08-0141 HV Customer Supplies

EDS 08-0142 Planning Requirements for Secondary Distribution Substations

EDS 08-0145 EHV Design

9.2 External Standards

BS 7671 Wiring Regulations

CDM 2015 The Construction (Design and Management) Regulations 2015

ENA E Rep2 Guidance on Security of Substations

ENA ER G81 Framework documents in 7 parts for competition in connection



Version: 5.0

Date: 21/07/2016


10 Dependent Documents

This document is referenced in the following documents, any of which may be affected by updates:

EDS 07-0021 Substation Unmade Access Road

EDS 08-0051 Customer Supplies between 6.6 and 33kV – Notes of Guidance for New Demand and Generation Connections

EDS 08-0141 HV Customer Supplies

EDS 08-0145 EHV Design

EDS 08-0148 Appendices to ENA ER G81

EDS 08-0150 London 33kV Distribution Network Design and Customer Supplies



Version: 5.0

Date: 21/07/2016


Appendix A - Appendices

A.1 Facilities Required for Indoor Extensible Switchgear

Facility Description

Test and tools storage

Lockable box or cupboard fixed to the wall for test bushings, test attachments, test devices and operational tools or handles as recommended by the equipment manufacturer

Platform to access high-level equipment

Fixed platform steps to UK Power Networks specification where access is required to high level operational equipment such as relays. Operational equipment should not normally be fitted more than 1.5m above floor level

Lighting Adequate lighting with a minimum of 500 lux maintained luminance with a uniform factor of 0.8 across the front and rear elevation for the whole the switchgear

Power Supplies Reliable Power Supplies for equipment and battery charging

SCADA equipment

SCADA equipment will be provided and installed by UK Power Networks where needed. Sufficient wall or floor space to allow the fitting of: tripping battery, SCADA RTU, SCADA battery (this may be integrated with the RTU) and pilot interface wall boxes for incoming and customer interface pilot terminations

Satellite dish aerial

External wall space may be required to fit a satellite dish aerial (may require planning permission). Where the wall construction of the Switch house is unsuitable for the fixing and support of the satellite dish the installation details on drawing EDS 07-0020-05 shall be used

A.2 Facilities Required for Ring Main Unit Switchgear

Facility Description

Test and tools storage

Lockable cabinet fixed to the wall or floor for test bushings, test attachments and operational tools, if not integral to the switchgear, as recommended by the equipment manufacturer

Platform to access high-level equipment

Fixed platform steps to UK Power Networks specification where access is required to high level operational equipment such as relays. Operational equipment should not normally be fitted more than 1.5m above floor level

Lighting Lighting for access

Power Supplies Reliable Power Supplies for equipment and battery charging

SCADA equipment

SCADA equipment will be provided and installed by UK Power Networks where needed. Sufficient space to allow the fitting of: tripping battery, SCADA RTU, SCADA Battery (this may be integrated with the RTU in some cases), and pilot interface wall boxes for incoming and customer interface pilot terminations

Satellite dish aerial

External wall space may be required to fit a satellite dish aerial (this may require planning permission). Where the wall construction of the switch house is unsuitable for the fixing and support of the satellite dish the installation details on drawing EDS 07-0020-05 shall be used