Electricity Specification 215
Issue 2
August 2009
New Connections of up to 1,500kVA
Capacity
Contents
1
Scope
2
General
3
Connection Arrangements
4
Equipment Records
5
Documentation
6
Documents Referenced
7
Keywords
Appendices A & B
Approved for issue by the
Technical Policy Panel
© 2010 Electricity North West Limited.
All Rights Reserved
The copyright of this document, which contains information of a
proprietary nature, is vested in Electricity North West Limited. The
contents of this document may not be used for purposes other than that for
which it has been supplied and may not be reproduced, either wholly or in
part, in any way whatsoever. It may not be used by, or its contents
divulged to, any other person whatsoever without the prior written
permission of Electricity North West Limited.
Electricity North West Limited. Registered in England & Wales. Registered No. 2366949. Registered Office: 304 Bridgewater Place, Birchwood Park, Warrington, WA3 6XG
Amendment Summary
Amendment
No.
Date
0
31/03/03
Brief Description and Amending Action
Issue 1
First Issue.
Prepared by:
1
27/07/07
P. Leather.
Authorised by: Paul Whittaker
Policy & Standards Manager
Issue 1
Reference to ES397 and requirement for customer to provide substation LV
supply added.
Prepared by: Peter Leather
0
26/08/09
Approved by the Technical Policy Panel and signed on its behalf by Simon
Rushton:
Issue 2
Company names changed. HV cable restricted to 95 and 300mm2.
Prepared by: Peter Leather
Approved by the Technical Policy Panel and signed on its behalf by Simon
Rushton:
1
31/03/10
Issue 2
New subsection 3.14 added on “Second Connection for Emergency Purposes”.
Prepared by: Peter Leather
Approved by the Technical Policy Panel and signed on its behalf by Simon
Rushton:
2
02/03/11
Issue 2
Fuse ratings, metering ct ratios and connection arrangements tabulated in new
Appendix B.
Prepared by: Peter Leather
Approved by the Technical Policy Panel and signed on its behalf by
Paul Whittaker:
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NEW CONNECTIONS OF UP TO 1,500KVA CAPACITY
1.
SCOPE
This Specification details the requirements for new connections and metering of HV (11/6.6kV) or
LV connections up to 1,500kVA directly connected to the Electricity North West Limited
(Electricity North West) electricity distribution network (Network), that connection being
intended to be adopted by Electricity North West. It is usually appropriate to provide connections
of up to 300kVA capacity in accordance with ES214.
This document shall be read in conjunction with ES210.
2.
GENERAL
2.1
Any variation to this specification shall be agreed, in writing, with the Network Planning
Policy Manager, Central Engineering Services (CES), Electricity North West prior to any
design being accepted by Electricity North West.
2.2
The Owner’s Works shall comply with the requirements of ES210.
2.3
It is a requirement that all work shall be carried out strictly in accordance with the
provisions of all relevant legislation and industry best practice.
2.4
The design shall ensure that Electricity North West can comply with all relevant Energy
Networks Association (ENA) Engineering Recommendations.
2.5
The Owner’s Works shall comply in all respects with the provisions of Regulations 3 (1),
6, 7, 8 (1), 8 (3), 9, 10, 12 to 14 and 17 to 22 of the Electricity Safety, Quality and
Continuity Regulations 2002 and with the Electricity at Work Regulations 1989.
2.6
Users will be supplied and metered at 11000/6600 or 400/230 volts. More than one User
may be supplied from a single transformer.
2.7
With any single circuit arrangement, the agreed supply capacity shall not be considered to
be firm.
2.8
The design of the connection shall take account of the following system requirements:
2.8.1
Maximum Fault Levels on the Network are:
 11 or 6.6kV = 250MVA
 LV = 19.4MVA (based on a supply from a maximum transformer size
of 1000kVA)
2.8.2
2.8.3
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The maximum short circuit ratings shall be:
 11kV =
13.1kA for 3 seconds
 6.6kV =
21.9kA for 3 seconds
 LV
27kA
=
The maximum earth fault current for both the 11kV and 6.6kV electricity
distribution network is 3300A, based on connection to a primary substation, with
three transformers operating in parallel.
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3.
2.8.4
The minimum impulse withstand level for new equipment connected to the 11kV
and 6.6kV distribution network is 75kV.
2.8.5
In particular, the rating of any switchgear and fusegear, forming part of any new
connection, must be fully compatible with all the system parameters, as set out in
this subsection 2.8.
CONNECTION ARRANGEMENTS
3.1
The connection provided from the Network may be one of the following arrangements:
3.1.1
Distribution Substation Connection with Provision for LV Network – see Figure
1 in Appendix A.
3.1.1.1 A maximum of three fuseways shall be made available to the User.
3.1.1.2 The maximum connected load, which is subject to the existing loading
on the Network, shall not exceed the following:
 1 Fused Way (400 or 500A Fuselink) up to 360kVA
 2 Fused Ways in Parallel (400A Fuselink) up to 575kVA
 3 Fused Ways in Parallel (400 or 500A Fuselinks) up to
1000kVA
3.1.1.3 Fuse ratings, metering ct ratios and connection types for the above
arrangements are tabulated in Appendix B.
3.1.1.4 Metering current transformers (ct) shall be positioned as shown in Figure
1 in Appendix A.
3.1.1.5 Where protection is to be provided by means of HV fuses, such as in a
switch-fuse, the maximum length of the11/6.6kV transformer cable
connection shall be 15m.
3.1.1.6 The exit point shall be as shown in Figure 1 in Appendix A.
3.1.1.7 The User’s connection to the exit point shall comply with the current
edition of British Standard (BS) 7671 (IEE Wiring Regulations).
3.1.2
Distribution Substation Connection with NO Provision for LV Network – see
Figure 2 in Appendix A.
3.1.2.1 This arrangement is available where there is to be no provision for LV
connection to the Network.
3.1.2.2 The maximum connected load, which is subject to the existing loading
on the Network, shall not exceed 1000kVA.
3.1.2.3 Where protection is to be provided by means of HV fuses, such as in a
switch-fuse, the maximum length of the11/6.6kV transformer cable
connection shall be 15m.
3.1.2.4 Metering cts shall be positioned as shown in Figure 2 in Appendix A.
3.1.2.5 The exit point shall be as shown in Figure 2 in Appendix A.
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3.1.2.6 The User’s connection to the exit point shall comply with the current
edition of BS 7671 (IEE Wiring Regulations).
3.1.3
11/6.6kV connection with NO LV Network Provision – see Figure 3 in
Appendix A.
3.1.3.1 This arrangement is available, where there is to be no provision for LV
connections to the Network and the substation is not to be looped into an
existing 11/6.6kV ring.
3.1.3.2 The maximum connected load, which is subject to the existing loading
on the Network, shall not exceed 1500kVA at 11kV or 1000kVA at
6.6kV.
3.1.3.3 Where protection is to be provided by means of HV fuses, such as in a
switch-fuse, the maximum length of the11/6.6kV transformer cable
connection shall be 15m.
3.1.3.4 Metering cts and voltage transformer (vt) shall be accommodated in an
HV metering unit and be positioned as shown in Figure 3 in Appendix A
3.1.3.5 The exit points shall be at the outgoing terminals of the HV metering
unit.
3.1.3.6 Part of the works to be adopted shall be a User-accessible emergency trip
facility that, when operated, will trip the 11/6.6kV Electricity North
West -owned switch.
3.1.3.7 The substation shall be fitted with a low voltage electrical installation
conforming with ES397, supply being provided, where necessary, by the
User.
3.1.4
11/6.6kV RMU connection – see Figure 4 in Appendix A
3.1.4.1 This arrangement is available where there is to be no provision for LV
connections to the Network and the substation is to be looped into an
existing 11/6.6kV ring.
3.1.4.2 The maximum connected load, which is subject to the existing loading
on the Network, shall not exceed 1500kVA at 11kV or 1000kVA at
6.6kV.
3.1.4.3 The maximum length of the11/6.6kV transformer cable connection,
connected to a switch-fuse, shall be 15m.
3.1.4.4 Metering cts and vt shall be accommodated in an HV metering unit and
be positioned as shown in Figure 4 in Appendix A
3.1.4.5 The exit points shall be at the outgoing terminals of the HV metering
unit.
3.1.4.6 Part of the works to be adopted shall be a User-accessible emergency trip
facility that, when operated, will trip the 11/6.6kV Electricity North
West -owned switch.
3.1.4.7 The substation shall be fitted with a low voltage electrical installation
conforming with ES397, supply being provided, where necessary, by the
User.
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3.2
Environmental Conditions
3.2.1
The equipment shall be designed and constructed to allow operation in
environments defined in Clause 6 of BS EN 60947-1 as follows:
3.2.1.1 Equipment that is housed in a controlled environment shall be suitable
for operation in Pollution Degree 2.
3.2.1.2 Equipment that is not housed in a controlled environment shall be
suitable for operation in Pollution Degree 3.
3.2.2
3.3
All equipment shall be protected from the deposit of excessive levels of dust and
from the influx of water or other substances liable to have a harmful effect.
Cables
3.3.1
The 11kV cable to be used shall be 95 or 300 mm² Triplex formation single core
‘quasi-dry design’ polymeric insulated with solid aluminium conductors in
accordance with ES400C9.
No other types or cross section of cable is permitted.
3.4
3.3.2
Where the point of connection is to a single transformer or two transformer
groups, the single core cable earth screen shall, as a minimum, carry the fault
current detailed in BS7870, Section 4.10 without sustaining damage.
3.3.3
Cable of 95mm2 cross-section may be used for the local connection between
switchgear and transformer and for connections to or from overhead lines of
equal or less current rating. In all other situations, 300mm2 cable shall be used.
3.3.4
All multicore and multipair cables shall comply with ES400C13.
Earthing Conditions
All installations are to comply with Electricity North West Electricity Policy Documents
332 and 333.
3.5
3.6
CableInstallation and Jointing
3.5.1
The installation and jointing of underground cables shall comply with the relevant
parts of ES400E4 and Electricity North West Code of Practice 411.
3.5.2
Small wiring shall be ferruled in accordance with ENA TS 50-19.
Substation Housings and Enclosures
Substation housings and enclosures shall comply with ES352.
3.7
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Cable Entry to Substations
3.7.1
11/6.6 kV cable entries to substations shall be made at the laying depth of the
cable, using red plastic duct of at least 150 mm diameter complying with
ES400D4. Cable joints are not permitted within entry ducts.
3.7.2
Bends in cable ducts shall be of no smaller radius than that permitted for the
cable.
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3.7.3
3.8
All entry ducts including any spare ducts and any ducts for earth conductors shall
be sealed against the ingress of gas and water after installation of the cable.
Sealing shall be achieved in an approved manner.
Routeing of Cables in Buildings
The following provisions apply where substations are sited within larger buildings and
11/6.6 kV cables must be routed through those buildings:
3.9
3.10
3.11
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3.8.1
Ducts for 11/6.6 kV cables within buildings shall be at least 150 mm in diameter.
Where ducted cable routes change direction in buildings, draw pits at least 1.5 m
square shall be provided, allowing for future repair or replacement of cables. No
single run of duct within a building shall exceed 25 m between draw pits.
3.8.2
Alternatively, covered trenches may be used to route cables. On completion of
cable work, cable trenches shall be filled with sand and covered with a 100mm
thick screed.
3.8.3
Where 11/6.6 kV cables are fixed to racks or cleated to walls, adequate
mechanical protection shall be provided.
3.8.4
All cables shall be securely supported. Particular consideration shall be given to
the secure support of cables in vertical runs.
11/6.6 kV Switchgear
3.9.1
Switchgear shall comply with ES314.
3.9.2
Approval for the use of specific types of switchgear shall be obtained, in writing,
from the Plant Policy Manager, CES, Electricity North West.
3.9.3
A switch-fuse shall be used to protect only a single ground-mounted transformer,
where the transformer loop does not exceed 15m in length.
3.9.4
Substation, circuit and plant identification shall as directed by the Design and
Construction Manager, Electricity Connections, Electricity North West, prior to
the commissioning of the equipment.
Transformers
3.10.1
Transformers shall be designed, manufactured, and tested in accordance with
ES322.
3.10.2
The ratings of transformers, to be adopted by Electricity North West, shall be
selected from the standard ratings allowed by current version of ENA TS 35-1
and shall be such that the initial utilisation factors are not less than 0.6.
3.10.3
The maximum transformer size to be adopted shall not exceed 1000kVA.
Metering Current Transformers, Fuse Cabinets and Remote Metering Cabinets
3.11.1
HV metering units shall comply with ES314.
3.11.2
All HV metering cts and vts shall be in accordance with ES501.
3.11.3
LV Transformer flange mounted fused metering chambers, cts and all ancillary
equipment including multicore boxes for metering purposes shall be in
accordance with ES319.
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3.11.4
3.12
Remote metering cabinets will be provided by Electricity North West on a
chargeable basis.
Metering Current Transformer Burdens
In order to ensure the accuracy of metering, the burden of the cts shall be restricted by
using multicore cable of at least 2.5mm2 copper cross-section and by limiting the length of
the cable connecting the cts to the meter. The designer shall ensure that the burden
connected to the cts is not excessive. As guide, the length of the cable should not exceed
25m for cts rated at 15VA.
3.13
31/03/10
Supplier
Where the connection is installed by an Independent Connection Provider (ICP), it shall be
responsible for ensuring that a Supplier is appointed on behalf on the User.
3.14
Second Connection for Emergency Purposes
3.14.1
The request for a second connection for emergency fire fighting lifts and
equipment, pressurised escape routes, or any other emergency purpose shall be
refused even if the Installer claims to satisfy the requirements of BS7671
“Requirements for Electrical Installations” also known as the “IEE Wiring
Regulations”.
3.14.2
The preferred option is for the Installer to install automatically started generation
(in accordance with BS 9999) for the following reasons:
3.14.2.1 There are adverse safety implications (inadvertent re-energisation, stray
earth and return currents etc) from having two connections. It is not
prudent to introduce a safety risk in order to mitigate another.
3.14.2.2 It cannot be assumed that the second connection will always be available
during 11/6.6kV (or higher voltage) faults. Even if a second connection
were to be derived from a separate source, Electricity North West could
not guarantee that this separation would be maintained.
31/3/10
3.14.2.3 It may be necessary to de-energise substations or feeders for fault
location or maintenance work. It follows that Electricity North West
cannot guarantee 100% availability of the second connection.
3.14.2.4 To be of practical use, the integrity of the second connection would need
to be continuously monitored. Electricity North West cannot undertake
this responsibility.
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3.14.3
The Installer shall be made aware that, although a second connection might
appear to be the cheapest option, it would not produce the desired level of safety
and might engender an unwarranted sense of security.
3.14.4
Distributors are absolved from the obligation to provide a quotation on demand
for a connection where it would not be reasonable in all the circumstances
(s17(1)(c) of the Electricity Act 1989 (as amended)). The issues listed above
mean that it is not reasonable to provide a second connection, where a safer and
more reliable option is for the Installer to install on-site generation.
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4.
EQUIPMENT RECORDS
The installer shall provide records of all equipment installed, using form C of ES210 and marked
upon the latest version of the Ordnance Survey MasterMap Topographic map for the area, at 1:500
scale with any complex details shown on 1:250 enlargements. Guidance on the provision of
records of underground equipment may be found in ES281, Part 6.
5.
31/3/10
DOCUMENTATION
Documentation shall be as described in ES210.
6.
DOCUMENTS REFERENCED
Non- United Utilities documents eg ENA TS, British Standards etc may be purchased by the
Installer or Owner. They will not, under any circumstances, be provided by Electricity North
West.
Non- Electricity North West Documents
Electricity Act 1989
Electricity Safety, Quality and Continuity Regulations 2002
31/3/10
Electricity at Work Regulations 1989
ENA ER G81 - Framework for Design and Planning, Materials Specification, Installation and
Records
ENA TS 35-1 - Distribution Transformers
ENA TS 50-19 - Standard Numbering for Small Wiring
BS 7671 - Requirements for Electrical Installations - IEE Wiring Regulations.
BS 7870 - LV and MV Polymeric Insulated Cables for use by Distribution and Generation Utilities
BS 9999 - Code of Practice for Fire Safety in the Design, Management and Use of Buildings
31/3/10
BS EN 60947-1 - Specification for Low Voltage Switchgear and Control Gear
Electricity North West Documents
EPD332 - Customer Installation Earthing
EPD333 - Supply System Earthing
CP411 - Cable Jointing
ES210 - General Specification for New Connections, Extensions and Alterations
ES214 - New LV Connections of up to 300kVA Capacity
31/3/10
ES281 - Company-specific Appendices to ENA ER G81
ES314 - 12kV & 7.2kV 21.9kA Switchgear
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ES319 - LV Distribution Fuseboards
ES322 - Ground-Mounted Distribution Transformers
ES352 - Design of Distribution Substations
31/3/10
ES397 - Electrical Installations within Distribution Substations
ES400C9 - 11kV Distribution Cables
ES400C13 - Multipair and Multicore Auxiliary Cables
ES400D4 - Plastic Ducts, Conduit & Accessories
ES400E4 - Installation, Commissioning and Repair of Solid Type Underground Cables Operating
on the United Utilities Low and Medium Voltage Systems and the Restoration of
Excavated Areas
ES501 - Metering Current & Voltage Transformers
7.
KEYWORDS
Connection
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APPENDIX A
Equipment to be
Adopted by
Electricity
North West
Point of Connection to
the Electricity
North West Network
CB or
SwitchFuse
15m Max with
Sw-fuse
LV Cabinet
Max Size
1000kVA
1, 2 or 3
Ways per
Phase
Fuses
400A
or 500A
Exit
Point
Remote
Metering
Cubicle
Multicore
M
Network
Connection
if Required
Customer’s
Cables
Figure 1 Distribution Substation Connection
with Provision for LV Network
Point of Connection to
the Electricity
North West Network
CB or
SwitchFuse
15m Max with
Sw-fuse
Remote
Metering
Cubicle
Max Size
1000kVA
M
Multicore
ACB
P
Equipment to
be Adopted
by ENW
Multicore
Exit
Point
P = Protection
Figure 2 - Distribution Substation Connection
with NO Provision for LV Network
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Point of Connection
to the Electricity
North West Network
Remote
Metering
Panel
CB or
swfuse
M
Multicore
Equipment to
be Adopted by
Electricity North
West
Multicore
Customer's
Emergency
Remote Trip
Facility
Exit
Point
vt
15m Max when
sw-fuse used
Customer's
Transformer
Figure 3 Connection with NO
Provision for LV Network
Point of Connection
to the Electricity
North West Network
Equipment to
be Adopted by
Electricity North
West
Remote
Metering
Panel
M
CB or
swfuse
Multicore
Multicore
vt
Exit
Point
Customer's
Emergency
Remote
Trip Facility
15m Max when
sw-fuse used
Customer's
Transformer
Figure 4 RMU Connection
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APPENDIX B
Fuses, Metering CTs and Connection Types
Maximum Import
Capacity Range
(kVA)
301 - 360
Fuses per Phase
1 x 500A
361 - 453
2 x 315A
454 – 575
2 x 400A
576 – 680
3 x 315A
681 – 864
3 x 400A
865 - 1000
3 x 500A
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Metering CT Ratio
Connection Type
500/5
Single way with
metering cts at
Electricity North West’s
LV Board.
800/5
2 parallel ‘consumer
ways’ with metering cts
at Electricity North
West’s LV Board..
1500/5
3 parallel ‘consumer
ways’ with metering cts
at Electricity North
West’s LV Board.
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