UK Power Networks
DSR 01 010
v6.0
Work in Live Substations – Safe Zones of Work
Owner
Name
Peter Vujanic
Title
Head of Health and Safety
Signature
01 May 2016
Date
Authoriser
Name
Dudley Sparks
Title
Operational Safety Manager
Signature
01 May 2016
Date
This document forms part of the UK Power Networks Integrated Management System and
compliance with its requirements is mandatory. Departure from these requirements may only be
taken with the written approval of the above authoriser.
Revision Record
What has changed?
Document reviewed minor word changes to s8 for clarity.
Version number
6.0
Date published
01/05/2016
Next review date
01/05/2019
Prepared by
C Shackell
Version number
5.0
Date published
07/08/2014
What has changed?
Owner and Authoriser updated. Stores codes added in Appendix 1 where
applicable.
Next review date
06/08/2017
Why has it changed?
Prepared by
N. Saunders
Version number
4.1
Date published
16/05/2012
Next review date
15/08/2014
Prepared by
N. Saunders
Why has it changed?
Re issue of DSRs
What has changed?
Minor word changes
Why has it changed?
Document reviewed
This printed document is valid at 29/07/17, check after this date for validity.
Page 1 of 16
UK Power Networks
DSR 01 010
v6.0
Who needs to know?
☐ All UK Power Networks Staff
☒ Asset Management
☒ Capital Programme
☒ Connections
☒ Contractors
☐ Customer Services
☐ Finance
☐ Legal
☒ G81 External website
☐ HR & Communications
☒ HSS&TT
☐ In Business HSS
☐ Safety Reps
☒ ICPs (Independent Connection Providers)
☒ IDNOs (Independent Distribution
Network Operators)
☐ Information Systems
☐ Meter Operators
☒ Network Operations
☐ EPN
☐ LPN
☐ SPN
☐ Distribution Capital Delivery
☐ Logistics
☐ Network Control
☐ Network Operations Connections
☐ Transport Services
☐ Strategy and Regulation
☒ UK Power Networks Services
☐ Airports
☐ Rail
☐ HS1, DLR & Commercial buildings
☐ MUJV / Allenby
☐ Business Development
☐ Others (specify)
Contents
1.0
2.0
3.0
4.0
5.0
6.0
7.0
8.0
Introduction and Purpose ............................................................................................. 3
Scope.............................................................................................................................. 3
Objective ........................................................................................................................ 3
References ..................................................................................................................... 3
Definitions ...................................................................................................................... 3
Responsibilities ............................................................................................................. 3
Records .......................................................................................................................... 3
Process Detail ................................................................................................................ 3
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UK Power Networks
DSR 01 010
v6.0
1.0 Introduction and Purpose
This procedure gives further guidance to the setting out of work zones in High Voltage (HV)
substations with exposed Live Conductors.
The Distribution Safety Rule (DSR) 4.5.1 specifies how a zone of work shall be identified
and delineated. The rule calls for the use of approved barriers or chains to be used.
Each of the distribution companies and National Grid (NG) had evolved a different method
of doing this and the Health and Safety Executive (HSE) identified some risk of confusion
where work is being done on shared sites. The Energy Networks Association (ENA)
produced a recommended barrier and roping system and UK Power Networks has
implemented a system that is consistent with the ENA recommendations. It is
supplemented by further requirements, where these have not been catered for in the ENA
recommendations (e.g. for Limitation of Access).
UK Power Networks (UKPN) has shared sites with NG. The NG standard (NSI6) is
extremely comprehensive and complex and designed to cover the very complex situations
that NG will encounter.
Some network operators may not have adopted the ENA recommendations. Therefore all
UKPN staff must be aware that they may encounter different barrier and roping systems on
shared sites.
2.0 Scope
This document applies to all UKPN Licence areas and private networks that are owned or
managed by UKPN.
3.0 Objective
To define the approved barrier and roping system used in UKPN, that delineates the
temporary zone of work required by DSR Rule 4.5.1.
To ensure that people working in UKPN substations with exposed HV live conductors can
clearly understand where they are to work.
4.0 References
DSR
Distribution Safety Rules
ENA
Energy Networks Association, position paper 01
NRSWA
New roads and street works act.
5.0 Definitions
DSR Section 2
Words in bold type are defined in the DSRs
6.0 Responsibilities
It is the responsibility of all UKPN employees and Managers and contractors working for
UKPN, to comply with the requirements of this procedure.
7.0 Records
An on-site record, in the form of a list as detailed in appendix A, will be kept of the barrier and
chain equipment.
8.0 Process Detail
8.1
Compared to other areas in the electricity supply industry, substation compounds with live
exposed HV conductors have been shown to have some of the highest risks of major
injury or death.
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DSR 01 010
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8.2
Open compound type substations contain many pieces of apparatus that are identical in
make and version. When work is done under a permit to work, often most of the
apparatus remains live and a small part of the substation is made dead and earthed in
accordance with DSR 4.1.
8.3
DSR 4.5 defines how work shall be managed by the Senior Authorised Person (SAP), to
ensure that all persons working in the substation understand what apparatus they are to
work on and also under which safety document they are to work.
The three safety documents are:

Permit to Work (PTW)
All apparatus and conductors detailed on the document are dead and earthed and
shall remain so for the duration of the work.

Sanction for Test (SFT)
Apparatus and conductors have been made dead and have been earthed initially
but may become live at any time with dangerous test voltages.

Limitation of Access (LOA)
Apparatus and conductors have not been made dead and have not been earthed.
Safety is ensured by maintaining safe working clearances to the live conductors.
8.4
It is a requirement that a suitably authorised person shall issue the safety document for
work in a substation compound containing live exposed HV conductors.
8.5
This Document provides a different demarcation system for each case. The purpose of
this is to give sufficient visual markers, to avoid confusion.
8.6
The different demarcation systems are not a substitute for the Senior Authorised safety
document issuer and the recipient of the safety document, ensuring that members of the
working party understand the nature of the work and the risks and dangers that are
involved. The demarcation systems are an important additional safety feature whose
purpose is to aid the safe management of the work site.
8.7
Marking the Work Zone and Access Route
Barrier and chain systems are not designed to be a physical barrier to stop
intruders gaining access to the apparatus or to keep members of the working
party in the work zone. The systems are designed to be a marker or indicator of
where the work zone is. However, at no time should any person climb over the
barrier chain or any part of the substation permanent enclosure to access the work
zone. Authorised entry must always be through the designated entrance.
To ensure that members of the working party can clearly know whether they are
inside the work zone, markers shall be placed inside the work zone (PTW and
SFT only).
All apparatus adjacent to the outside of the work zone shall be clearly marked with
Danger Notices. The notices shall be placed to be visible to anyone approaching
the zone and anyone inside the zone.
If the work zone can sensibly be extended to within one metre of the gates of the
substation compound without compromising safety, then this should be done to
limit movement of people in the compound. The remaining gap between the gates
and the start of the work zone will allow others access to the other parts of the
compound that are outside of the demarcated work zone.
If the work zone cannot be sensibly extended to within one metre of the gates of
the compound, then an access route may be marked out, if it is necessary to
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DSR 01 010
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prevent Danger.
It is important that all people working on the site understand that this marked
access route may pass close to, or under live conductors and that the safety
rules 4.5.4 and 4.5.5 regarding movements of long objects etc. must be complied
with.
The entrance to the work zone will be formed by two purple coloured cones. The
rest of the access route shall be indicated by two rows of yellow cones fitted with a
white sleeve with black lettering saying ‘ACCESS ROUTE’. The width of the
entrance and access route shall not be more than 1m wide for pedestrians. If
vehicular or plant access is required, the entrance may be widened but should not
normally exceed 1.5m. A notice shall be placed at the entrance showing who the
safety document holder is and how to contact them.
In the case of a Permit to Work, the notice will state that no person shall enter the
work zone whilst work is taking place, until they have made contact with the safety
document holder and been fully inducted into the work.
In the case of a Sanction for Test, the notice will state ‘no entry without the
permission of the safety document holder as identified below’.
8.8
If the access route passes under live exposed conductors, then the warning
notice for overhead live equipment notice shall be displayed at the beginning of
the route for access and end of the route for egress, so that it can clearly be seen
when travelling along the route in either direction. In addition, danger notices
shall be attached to apparatus containing live conductors and conductor
supports along and adjacent to the access route.
General Specification (PTW and SFT only)
The barrier will be a yellow and black plastic chain with closed links.
As the ground will probably contain cables and earth conductors, any supports
for the barrier will be self-supporting and not penetrate the ground
The supports will be yellow plastic cones. They will be weighted at the base with
facility to add weight where required. The supports will have a slot moulded into
the top to attach the chain.
When erected, the cones shall be sufficiently close so that the chain is at least
500mm. above ground level.
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UK Power Networks
8.9
DSR 01 010
v6.0
Permit to Work Zone
Perimeter boundary:
Entrance:
Inside the zone:
Yellow cones.
Yellow and black chain.
Zone will have an open entrance, denoted by two purple cones
leading to the entrance.
Access notice to be positioned next to the entrance. Blue text
on white background.
Yellow cones with green sleeves.
Live conductors over work area notice (if required). Black text
on yellow background (additional signs made of a magnetic
material for ease of fixing, may also be used).
Fig.1 Ideal layout showing cones and chain for a PTW zone.
Figure 1 shows an idealised layout of the cones and chain for a PTW zone. It is
the duty of the Senior Authorised Person to arrange the chain and cones to
make it as clear as possible where the work zone is.
The DSR expressly forbids attaching the chain to any structure supporting
electrical apparatus or conductors. It should be obvious that if the chain was
attached to a structure, then it is not clear if the structure is included or excluded
from the work zone.
Where possible the zone shall be arranged so that no structure carrying Live
exposed conductors is within the zone. This includes any conductors that over
sail the work zone. If this is not possible, then the structure will be clearly marked
with Danger Notices and Danger Do Not Climb bands (additional signs for
example, made of a magnetic material for ease of fixing may also be used).
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DSR 01 010
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In addition, yellow signs warning of live conductors over work area shall be
placed at the entrance to the zone.
It is permitted to attach the chain to the earthed fence surrounding the substation
compound.
The area shall also be adequately lit.
8.10 Sanction for Test zone
Perimeter boundary:
Entrance:
Inside the zone:
Yellow cones.
Yellow and black chain.
Zone entrance will be closed by yellow and black chain. The
entrance will be denoted by two purple cones leading to the
entrance. Qualified ‘No entry’ sign. White text on red background.
Yellow cones with red sleeve having white text denoting ‘Test
Area’. Live conductors over work area notice (if required). Black
text on yellow background.
Fig.2 Ideal layout showing cones and chain for a SFT zone.
8.11 Working and Access Clearances
The work zone barrier shall be sited to comply with the requirements of section 4.5
of the Distribution Safety Rules and establish the necessary Working and Access
Clearances.
The movement of materials and tools etc., through the access route, shall be
controlled to comply with the requirements of section 4 of the DSR.
8.12 Management of Work under a PTW or SFT
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UK Power Networks
DSR 01 010
v6.0
Where physical demarcation is to be used this must be:
Erected after completion of all safety precautions and before any safety document is
issued

Removed after the clearance of the safety document(s).
The safety document shall be issued as defined in section 4 of the DSR by the
Senior Authorised Person.
Once the safety document has been issued, the issuer shall satisfy himself that
the work is being done safely. The work shall be visited at regular intervals by the
issuer, or a person with equivalent authorisation and knowledge of the job. For
extended periods of work, the time between visits shall not exceed three days,
whenever actual work is in progress.
For compounds or enclosures where there is only one item of equipment, it
will not be necessary to deploy the yellow cones and chain to mark out the work
zone. All other requirements must be implemented e.g. signs at work zone
entrance, cones with appropriate sleeves inside the zone to indicate what type of
zone has been established, etc.
As there must only be one entrance to a demarcated zone, if there is more than
one gate or door to this compound or enclosure, then an appropriate Do Not Enter,
This is a PTW/SFT Zone warning sign must be place at these other gates or doors.
8.13 Limitation of Access Work Zone
General
A limitation of access is a safety document that is defined in the DSR. It is used
to explain how a person can work safely in the vicinity of live exposed conductors
and other places in substations.
The equipment that presents danger will not have been made safe in accordance
with section 4.1 of the DSR. Instead, safety is achieved by staying a safe distance
away from the conductors.
This safe distance should normally be much greater than the working and access
clearances defined in the DSR.
Within a substation (s/s) that has exposed live HV conductors the LOA is often
issued to allow work at ground level. The work may or may not include
excavations.
It is permissible to write a LOA that simply explains where the work is to be done
and where the dangers are.
For some work, it might be desirable to limit the access of the person, by erecting
a barrier. It is possible that a person, who was previously working in a PTW zone
one day, might just mistakenly believe that the apparatus inside the LOA zone
that he is currently working in is dead!
Many of the people who will work under a LOA will be contractors, whose main
work is non electrical. However well these people are trained, they will not have
the same level of practical experience as people whose work is predominantly
electrical. The awareness that an experienced person develops will not be there.
For this reason, it is imperative that any work under a LOA must be carefully
managed. In fact work under a LOA should attract a higher level of management
and supervision than work under a PTW. Traditionally this has not been the case
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DSR 01 010
v6.0
and work under a LOA is looked on as being less of a management problem than
most.
If the LOA zone is all the Substation
Where the LOA is written to allow access to the whole s/s, no specific barrier
systems need be erected. The recipient of the LOA will be issued with the
document on site. Furthermore, the recipient is required to show the issuer that he
understands the document and how the work is to be done. The recipient will
demonstrate that he understands the dangers within the s/s and that any safety
precautions to prevent contact with live exposed conductors are fully understood.
The issuer will also satisfy himself that any other members of the working party
have sufficient understanding of the work and the dangers. The issuer will check
that all members of the working party can demonstrate competence in the work
activity.
If there is equipment in the s/s that has a known danger due to catastrophic
failure, then a LOA will not be issued covering the whole s/s.
The issuer will satisfy himself that the recipient understands the work and that it is
practical to do the work without infringing sensible safety clearances. The exact
clearances must be determined by the issuer, taking into account:

The nature of the work

The arrangement of the conductors

The experience and competence of the recipient and the other
members of the working party
The issuer, or a person with at least the same level of authorisation and knowledge
of the work, will visit the site during the work, to ensure that the safety precautions
are being complied with. Where the work takes place over an extended period, the
period of time between visits shall not exceed three days, whenever actual work is
in progress.
Defining a Work Zone Area for Work under a LOA
The work zone will be indicated by the use of blue coloured cones (no plastic
chain). The cones shall be 750mm in height.
The area indicated by the cones does not form an island within which the person
will work but helps better explain those parts of the compound the recipient and
working party are allowed to work in. Where such an area of work is being
indicated by the cones and is within a substation enclosure or compound
containing live exposed HV conductors, then the LOA must be issued by a
suitably Authorised Person.
Work under a LOA within Indoor Areas
Where work is controlled by a LOA inside rooms where no exposed conductors
are present, then there is no need to erect barriers. However, if the LOA confines
the work to a specific area, or item of apparatus or plant, then this will be made
clear on the LOA. The equipment shall be labelled clearly to show where the work
is to be done.
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8.14 Non-Electrical Work Zones (i.e. Civil Works)
Non electrical hazards e.g. civil works will be demarcated using red and white
demarcation or barrier systems. Suitable barrier systems would be those which comply
with NRSWA requirements.
Non electrical hazards such as broken cable trench covers may initially be guarded by
yellow cones fitted with a red and white sleeve, with the word ‘HAZARD’ in black lettering.
These temporary hazard cones should be replaced as soon as possible by the red and
white barrier system mentioned above.
8.15 Routine Ground Level Activities
Activities such as the application of vegetation inhibiting chemicals and pumping out of
transformer bunds are routine ground level activities and do not require the issue of a
safety document, provided the person undertaking the work:
i) Holds a current competency for performing this activity.
ii) Holds a current competency for “Enter Substations & Avoid Danger Inside “or legacy
“access into substations containing live exposed conductors”.
iii) The person undertaking the work completes an on-site risk assessment.
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DSR 01 010
v6.0
Appendix 1
UK Power Networks
Substation Barrier Kit to meet the requirements of DSR 01 010
Specification for Materials
132kV Standard kit
ITEM
NOTE
NUMBER
SUPPLIER
REF/Stor
es code
Yellow cone
1
25
a
Purple cone
2
2
a
Blue cones
3
10
b
Yellow/black plastic chain (m)
4
65
2173W
Green sleeve
5
8
c
Red sleeves (TEST AREA)
6
8
c
White sleeve (ACCESS ROUTE)
7
2
c
Red and white sleeve (HAZARD)
8
1
c
Road cones (red and white)
9
10
21727W 18”
21728G 30”
Cone mounted yellow notice (LIVE
CONDUCTORS OVER WORK AREA)
10
2
d
Cone mounted blue notice (ACCESS POINT)
11
1
d
Cone mounted red notice (TESTING AREA)
12
1
d
Magnetic yellow/blue notice (DANGER Treat
as Live)
13
6
e
Magnetic red/yellow notice (DANGER DO
NOT CLIMB/LIVE CONDUCTORS
OVER WORK AREA)
14
6
e
Warning notice (DO NOT ENTER PTW)
15
1
e
Warning notice (DO NOT ENTER SFT)
16
1
e
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v6.0
33kV Standard kit
ITEM
NOTE
NUMBER
SUPPLIER
REF.
Yellow cone
1
23
a
Purple cone
2
2
a
Blue cones
3
10
b
Yellow/black plastic chain (m)
4
55
2173W
Green sleeve
5
8
c
Red sleeves (TEST AREA)
6
8
c
White sleeve (ACCESS ROUTE)
7
2
c
Red and white sleeve (HAZARD)
8
1
c
Road cones (red and white)
9
10
21727W 18”
21728G 30”
Cone mounted yellow notice (LIVE
CONDUCTORS OVER WORK AREA)
10
2
21681H
Cone mounted blue notice (ACCESS POINT)
11
1
21682S
Cone mounted red notice (TESTING AREA)
12
1
21683C
Magnetic yellow/blue notice (DANGER Treat
as Live)
13
0
21684M
Magnetic red/yellow notice (DANGER DO
NOT CLIMB/LIVE CONDUCTORS
OVER WORK AREA)
14
0
21685W
Warning notice (DO NOT ENTER PTW)
15
1
21686G
Warning notice (DO NOT ENTER SFT)
16
1
21687R
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DSR 01 010
v6.0
Cones and sleeves
Note 1.
Yellow plastic cones shall be 1275mm high, weighted at the base with facility to add
weight where required. Yellow cones shall have slots moulded in the top to attach
chain.
Note 2.
Purple cones are otherwise as yellow i.e. 1275mm high, weighted and with moulded
slots.
Note 3.
Blue plastic cones shall be 750mm high, weighted as above but with no facilities for
the attachment of chains.
Note 4.
Yellow and black plastic chain (6mm gauge) with closed links to fit in slots in cone
tops.
Note 5.
Plain green sleeve 1000mm high from the base of the cone.
Note 6.
Red sleeve 1000mm high from the base of the cone with white text saying TEST
AREA printed with the letters arranged vertically one above the other.
Note 7.
White sleeve 1000mm high from the base of the cone with black text saying ACCESS
ROUTE printed with the letters arranged vertically one above the other.
Note 8.
Sleeve 1000mm high from the base of the cone with red and white bands with black
text saying HAZARD printed with the letters arranged vertically one above the other.
Note 9.
Road cones to NRSWA requirements
Cone mounted notices
Note 10. Cone mounted warning notice with black lettering on a yellow background. Text is: LIVE CONDUCTORS OVER WORK AREA and a “thunderbolt” symbol is enclosed in
a triangle (See illustration). Notice dimensions are 700mm high, 600mm wide for cone
mounting. The notice will be shown on both sides of the cone.
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Note 11. The cone mounted access point notice shall show who the safety document holder is
and how to contact them. Text is ACCESS POINT NOTICE. ACCESS ONLY BY THE
WORKING PARTY. NO PERSON SHALL ENTER THIS WORK ZONE, WHILST
WORK IS TAKING PLACE, UNTIL THEY HAVE MADE CONTACT WITH THE
SAFETY DOCUMENT HOLDER AND BEEN FULLY INDUCTED INTO THE WORK.
SAFETY DOCUMENT HOLDER. CONTACT DETAILS. A weatherproof facility is
needed to mark the name of the document holder along with his contact details. The
cone mounted notice will have blue text on a white background and will appear on
one side only of the cone to the dimensions shown above.
Note 12. The cone mounted testing area notice is a qualified “No entry” sign with white text on
a red background. Text is: - TESTING AREA. NO ENTRY WITHOUT THE
PERMISSION OF THE SAFETY DOCUMENT HOLDER AS IDENTIFIED BELOW.
SAFETY DOCUMENT HOLDER. CONTACT DETAILS. A weatherproof facility is
needed to mark the name of the safety document holder and the contact details. The
cone mounted notice will have white text on a red background and will appear on one
side only of the cone to the dimensions shown above.
Signs for attachment to structures, gates or doors
Note 13. Notice DANGER Treat as Live. Notice is as the illustration below (i.e. yellow/blue on a
white background) with dimensions of 275mm X 350mm and printed on magnetic
material for attachment to steel cabinets and steel structures.
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Note 14. Two part red/yellow magnetic notice 250 x 430mm. Notice in magnetic material with
two parts: - right hand part - white lettering on a red background with a crossed red
circle and the text: DANGER
DO NOT CLIMB
Left hand part - black lettering on a yellow background with a “thunderbolt“symbol in a triangle
and the text:LIVE CONDUCTORS
OVER WORK AREA
Note 15. Weatherproof warning notice with white lettering on a red background: - Dimensions
300mm X 350mm.
DO NOT ENTER
THIS IS A PERMIT TO WORK ZONE
Note 16. Weatherproof warning notice with white lettering on a red background: - Dimensions
300mm X 350mm.
DO NOT ENTER
THIS IS A SANCTION FOR TEST ZONE
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Supplier Details
a) Glasdon UK Ltd, Preston New Road, Blackpool, Lancs, FY4 4UL,
Tel: 01253 600410
b) Greenham Limited, see internet for local depots
c) JSP Ltd, Worsham Mill, Minster Lovell, Oxford, OX29 0TA, Tel: 01993 826050
d) Pro-tect Safety Signs, Puxton Barn, Weston-Super-Mare, Somerset,
BS24 6TA, Tel: 01934 834200
e) Brissco signs and graphics, Block 9 Unit 25 Cater Road, Bishopsworth, Bristol,
BS13 7TX, Tel: 0117 3113 777
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