Download DSR 01 016 How to Ensure Low Voltage

UK Power Networks
DSR 01 016
v10.0
How to Ensure Low Voltage Customers Have Correct
Polarity and Phase Rotation
Owner
Name
Peter Vujanic
Title
Head of Health Safety and Environment
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?
Removal of the neutral and earth conductors is now allowed. Changes to
Section 8 and the testing regime required. Removal of references to the LV
Handbook. Some grammatical changes. Polarity check form altered (DSR 01
016a) Standard letter of disconnection added (DSR 01 016b).
Version number
10.0
Date published
01/05/2016
Next review date
01/05/2019
Prepared by
D. Milton
Why has it changed?
Full review of document
Version number
9.0
Date published
25/09/2015
What has changed?
Rewording of 3rd paragraph of section 6.1 to improve clarity and “where
practicable” added to first sentence of section 8.1. Form DSR 01 016a v1.0
has been reviewed, there are no changes (now v2.0).
Next review date
19/03/2017
Prepared by
D. Milton
Version number
8.0
Date published
07/07/2015
Next review date
19/03/2017
Prepared by
D. Milton
Why has it changed?
Feedback on recently issued procedure.
What has changed?
The advance warning letters moved to NOP 50 018 (Pre-Arranged
Interruption Procedure). Methods of completing the polarity tests removed
and referenced to The LV Operations Handbook. Inclusion of a polarity test
record. Blank cut-out fuse replaced and sealed following the tests. Forms a-f
have been withdrawn and replaced by a new form ‘DSR 01 016a Polarity
Record’.
Why has it changed?
The existing 6 appendices belong in alternative procedures.
This printed document is valid at 01/05/16, check after this date for validity.
Page 1 of 8
UK Power Networks
DSR 01 016
v10.0
Who needs to know?
☐ All UK Power Networks Staff
☒ Asset Management
☒ Capital Programme
☒ Connections
☒ Contractors
☐ Customer Services
☐ Finance
☐ 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
☐ Commercial Services
☐ 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
Testing Locations ......................................................................................................... 4
Instruments for checking supply ................................................................................. 5
Process.......................................................................................................................... 5
Tests required ............................................................................................................... 6
This printed document is valid at 01/05/16, check after this date for validity.
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UK Power Networks
DSR 01 016
v10.0
1.0 Introduction and Purpose
Distribution Safety Rule 8.1.6 requires polarity to be checked at an appropriate point before
connecting a new supply or reconnecting a supply following rearrangement of conductors.
Tests will be required following any work on the network which may affect the polarity of
any supply. This includes installation of new or replacement underground or overhead
circuits and transformers. During a fault situation (where possible) a comparison will be
made of results before and after the work.
2.0 Scope
All work within the UK Power Networks licensed area networks, including the replacement
of underground or overhead circuits and transformer changes, which may affect the polarity
of any supply being undertaken by UK Power Networks staff and their contractors.
This document does not address Polarity Testing for Metering Service Providers
undertaking meter work on behalf of Suppliers, or any work undertaken by Independent
Connection Providers who should adhere to their own Codes of Practice and Safe Systems
of Work.
Tests detailed in this procedure and associated documents shall be carried out before
supply is left connected or reconnected to a customer’s installation.
Where installations include non-metered supplies then the polarity checks should include
checking the incoming supply to the cut-out and the customer’s isolation point.
3.0 Objective
To ensure that customers receive the correct polarity and phase rotation and that all low
voltage services provided by UK Power Networks comply with the Electricity, Safety,
Quality and Continuity Regulations 2002 (ESQC Regulations).
To ensure that even if a mistake is made during our work that a customer is not supplied
with reversed polarity.
4.0 References
The Electricity Safety, Quality and Continuity Regulations 2002
Distribution Safety
Rules
(Principally Section 8)
Engineering
Recommendation G14
Protective Multiple Earthing: Recommended Principles for
Testing to Ensure Correct Polarity
UK Power Networks
Jointing Manual
2.4 – New harmonised phase colours and section 5.0
GOP 15
LV Operations including linking, fusing, switching and cut-outs
JLV 03
LV Jointing (Including Cable Identification, Stripping and
Preparation)
DSR 01 016a
Polarity Record
This printed document is valid at 01/05/16, check after this date for validity.
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UK Power Networks
DSR 01 016
DSR 01 016b
Customer Left Off Supply Due To Safety Issue
NOP 50 018
Pre-Arranged Interruption Procedure
EDS 06-0004
Earth fault loop impedance requirements
LV Operations
Handbook
Section 5
v10.0
5.0 Testing Locations
Tests are to be carried out at a position that ensures that polarity, and where relevant
rotation, is correct before supply is provided for the first time or permanently reconnected
after work on the network.
All displaced conductors shall be clearly marked before being disconnected. Best practice
is for the person marking the conductors should be available during re-connection to reduce
the possibility of cross connection of the conductors.
A pole top service box, with clearly identified phase and neutral terminations, would also be
an acceptable position for before and after tests, providing no work has been carried out on
the customer’s side of the box.
For looped service changes it will be acceptable to complete tests at just one supply point,
provided no cut out or neutral block changes have taken place.
5.1
Examples of appropriate test location
For a transformer change, before and after tests at the transformer low voltage links or
fuses, providing no work has taken place on the outgoing side of the fuses or links.

For work where all cables are live, phasing tests during jointing will normally be
adequate.

For fault work, where before work tests are not always possible, a satisfactory test at
two cut-outs downstream of the work will be sufficient. By checking at two locations
there is an acceptably low risk of a reversed supply at both cut-outs which has been
corrected in the meter tails, or on the customer’s installation. If there is only access
to one customer then a check at the cut-out, meter and customer’s installation will
provide the same standard of check.

Where mains work overhead or underground, not involving services, affects several
customers it will be possible to confirm correct polarity and phasing without access to
all cut-outs. It will be sufficient to carry out a before and after test at a cut-out meter
and customer’s installation beyond the point of work.

For mains work polarity tests should be completed after jointing through cores but
before filling joint boxes, wherever this is possible. It is only necessary to remove all
accessible cut-out fuses where core identification is in doubt.

For Overhead line replacement or repair of more than one conductor, only those
services with access to the meter position will be re-connected, with the polarity tests
being made upon reconnection.

Where access to the consumer unit is not available the supply will be left
disconnected. The pre disconnection Polarity check form shall be available when
completing the re-energisation checks and will record the test results.
This printed document is valid at 01/05/16, check after this date for validity.
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UK Power Networks
DSR 01 016
v10.0
An example letter where customers are left off supply following a planned shutdown is
shown in NOP 50 018 Pre-Arranged Interruption Procedure.
Although a continuity tester may be used for core identification on dead cables,
further polarity and phasing checks shall be made after the cable has been made
live.
6.0 Instruments for checking supply






6.1
Test lamp
Testoscope neon indicator
Voltstick live conductor indicator
Socket tester
Phase Rotation Indicator
Voltmeter
Methods of Testing
Appropriate Personal Protective Equipment (PPE) must be used when removing and
replacing cut-out fuses and when working near live terminals.
The first and last stage of any testing is to check that any testing device is working.
For all cut-outs both a test lamp and either a Voltstick or Testoscope (neon) should be used
to check for reverse polarity and open circuit neutral. Do not rely on only one device. The
user may prefer to use a Voltstick as the Testoscope requires gloves to be removed to
provide a reliable return path. A Testoscope shall be used when a Voltstick does not give a
reliable indication.
If a test lamp fails to light it should be checked against a known live source or with an
approved test lamp tester. If a Testoscope or Voltstick fails to light it should be checked
against a known live source.
A socket tester used on PME systems cannot detect a cross polarity on its own. Used with
the correct tests it will confirm internal wiring.
The consumer unit shall be checked by using a Voltstick. This can be achieved by running
the Voltstick along the consumer unit fuses.
At no point should the consumer unit be dismantled by the person completing these polarity
checks. In the case of an iron clad consumer unit then a discussion with your line manager
shall decide an appropriate method of testing polarity of the work.
7.0 Process
7.1
General
On completion all services and equipment shall comply with current Engineering Standards
and Manuals.
On all planned work polarity and if relevant rotation tests shall be carried out before supply
disconnection these shall be recorded on the polarity record form DSR 01 016a or an
equivalent be it paper or electronic format.
During any part of the polarity checks if an unexpected result/reading is found then
the individual undertaking the test will stop and consult with a Line Manager.
This printed document is valid at 01/05/16, check after this date for validity.
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UK Power Networks
DSR 01 016
v10.0
Incorrect Polarity – Incoming up to the customer consumer unit
7.2
When carrying out the pre disconnection tests, if a customer is found to be receiving
incorrect polarity or phase rotation the customer’s installation shall be isolated. All meter
tails and any PME earth connections shall be removed from the cut out.
A Line manager shall be contacted before continuing with any further work. This report
should include details of any cut out or meter seals, which should be retained for further
investigation.
The Line Manager shall arrange for an electrician to complete further checks on the
customer’s installation before re-energising the customer’s supply.
The craftsman shall not attempt to solve the problem on a customer’s installation.
Whenever possible, for 3 phase supplies test the rotation. Any nonstandard phase rotation
shall be recorded on the job paperwork and also marked on site by means of a suitable
temporary label. This label shall be removed following the after work tests. Existing phase
rotation shall not be changed unless specifically required by the job instruction.
On completion of the tests the cut-out shall, where practicable, be sealed with a blank cutout fuse carrier. The customer neutral and earth connections shall be removed from the cutout and shrouded.
Any incorrect polarity or phase rotation shall be reported to Airline.
Incorrect Polarity – Customer Wiring from the consumer unit
7.3
If incorrect polarity or rotation is found on the customer’s internal wiring then the customer
must be informed and the supply shall, where practicable, be sealed with a blank cut-out
fuse carrier.
In either case a notice giving the reasons for the de-energisation plus a copy of
Regulation 26 of the Electricity, Safety, Quality and Continuity Regulations 2002, which
covers disconnections, shall be left with the customer. Refer to DSR 01 016b
Observation/Disconnection letter
7.4
Planned work
Where access is required to a premises, whoever organises the work shall follow
NOP 50 018 Pre-Arranged Interruption Procedure.
Where the required access to the cut-out, consumer unit, sockets is not available at the
start of planned work a decision will be made by the Line Manager whether to continue with
the shutdown. Factors to consider will include the number of other customers that are
affected, time of year, weather conditions. If work continues any customer that has not
provided access to the cut-out, meter, consumer unit, shall be disconnected before any
work that may affect the polarity or rotation of their individual supply.
7.5
Fault work
Wherever possible the cut-out fuse or fuses of any consumer, where the polarity may be
affected should be removed and if still live, the polarity, and where relevant rotation,
checked before the work is carried out and recorded on the polarity check form. It is
accepted that removal of all cut-out fuses is not always possible where a large number of
customers are involved or where access is difficult, such as during the night. Refer to
section 5.1 for examples.
8.0 Tests required
8.1 All supplies with meter and customer’s equipment connected
For any service connections, where practicable, there should be before and after testing at
This printed document is valid at 01/05/16, check after this date for validity.
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DSR 01 016
v10.0
the cut-out (this is not possible for new connections). This is because of the risk of a double
cross situation where a cross at the cut-out has been corrected by a second cross on the
consumer’s installation testing will be required at the consumer’s switchgear and at two
separate sockets.
Measuring the earth loop impedance and voltage before work will help determine the cause
if poor readings are found after the work. The Earth Fault Loop Impedance readings shall
comply with EDS 06-0004 (Earth Fault Loop Impedance Requirements).
EDS 06-0004 includes a flowchart to assist staff with the process and any remedial work to
be completed.
Any non-standard cut-outs especially re-wireable types or those with a neutral link shall be
changed. This will include any inverted/upside down cut outs.
Before alteration / renewal work starts complete the following and record using DSR
01 016a or an electronic equivalent (this may not be possible for fault work).
The following shall apply after the tests above have been completed:a) Isolate customers switchgear and generation if fitted
b) Check using approved voltstick on cut out fuse(s) and associated tails
c) Remove the cut-out fuse(s)
d) The customer neutral and earth connections shall be removed from the cut-out.
e) Test the polarity at the cut-out
f) Measure and record the earth loop impedance value
g) Measure and record the supply voltage(s)
h) For three phase supplies test for correct rotation at the cut-out
i) For all supplies affix phase identification label(s)
j) Where practicable, insert a blank sealed cut out fuse
k) For unmetered supplies polarity shall be tested at the customer’s point of isolation
After completion of the work
a) Test the polarity at the cut-out
b) Measure and record the earth loop impedance value
c) Measure and record the supply voltage(s)
d) For three phase supplies test the phase rotation at the cut-out.
e) Re-connect Neutral and Earth connections
f) Replace the cut-out fuses
g) Fit a harmonised wiring caution label where the meter tails are to different colour
standards
h) Test for polarity on the incoming and outgoing sides of the meter
i) Turn on customers switchgear
j) Test for polarity at the customer’s switchgear using a voltstick
This printed document is valid at 01/05/16, check after this date for validity.
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DSR 01 016
v10.0
k) Where sockets are available use a Socket Tester in the cooker circuit and or two
separate sockets.
l) If applicable test a 3 phase motor for correct rotation
m) Seal the cut-out and where known fit phase identification label(s)
n) Turn on customer generation if fitted
This printed document is valid at 01/05/16, check after this date for validity.
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