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Introduction
Regulation 610.1 of BS 7671:2008 IEE Wiring
Regulations Seventeenth Edition requires that
every installation shall, during erection and on
completion before being put into service, be
inspected and tested to verify, so far is reasonably
practicable, that the requirements of the
Regulations have been met.
Regulation 610.4 states that for an addition or
alteration to an existing installation, it shall be
verified that the addition or alteration complies
with the Regulations and does not impair the
safety of the existing installation.
The guidance given in this booklet is divided into
two sections, tests carried out before the
electrical installation is energized and those
carried out with the installation energized.
The tests specified by Regulation should be
carried out in the following sequence:
A. Tests before the supply is connected.
1. Continuity of protective conductors including
main and supplementary equipotential
bonding. (Regulation 612.2.1)
2. Continuity of ring final circuit conductors
(Regulation 612.2.2)
3. Insulation Resistance (Regulation 612.3)
4. Polarity (Regulation 612.6)
5. Earth electrode resistance (Regulation 612.7)
B.Tests with the electrical supply
connected.
1. Earth fault loop impedance (Regulation 612.9)
4
2. Check of phase sequence (Regulation 612.12)
3. Functional testing (Regulation 612.13)
4. Verification of voltage drop (Regulation 612.14)
A. Tests before the supply is connected
1. Continuity of protective conductors
including main and supplementary
equipotential bonding.
Every protective conductor, including circuit
protective conductors, the earthing conductor,
main and supplementary bonding conductors
should be tested to verify that all bonding
conductors are connected to the supply earth.
Tests are made between the main earthing
terminal (this may be the earth bar in the
consumer unit where there is no distribution board
present) and the ends of each bonding conductor.
The reading obtained at each point should be a
low resistance value. See Diagram 1.
Main Earthing Terminal
CONSUMER UNIT
(only Earth Bar
shown for clarity)
BS 951 Clamp with Label
to be used within 600mm
of the meter union outlet
or at the point of entry
where the meter is
external to the building
Diagram 1: Continuity of Protective Bonding Conductors
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i. Continuity of circuit protective
conductors (CPC)
The purpose of this test is to verify that the
CPC forms a continuous path around the
circuit under test.
The test is carried out (using either or both
methods shown) as follows:
Test Method 1:
a) Temporarily link the line conductor to the
CPC in the Consumer Unit.
b) Test between the line and the CPC at each
accessory point e.g. a ceiling rose, switch or
socket outlet.
The reading obtained at each accessory point
should be a low resistance value.
The resistance measured at the extremity of
the circuit is the sum of the resistances of
the
line
conductor
and
protective
conductor (R
+ R
) and should be equal to
1
2
the value obtained by using Tables 9A, 9B,
and 9C in the IEE On-site Guide. See
Diagram 2.
Test Method 2:
Using a long test lead, test between the earth
bar in the consumer unit and the CPC at each
accessory point.
The reading obtained at each accessory point
should be a low resistance value.
The resistance measured at the extremity of the
Tried. Tested. Trusted.
circuit is the resistance of the circuit protective
conductor (R
) and should be equal to the value
2
obtained by using tables 9A, 9B, and 9C in the
IEE On-site Guide. See Diagram 3.
NOTE:
NEUTRAL
CONDUCTOR
OMITTED FOR
CLARITY
ACCESSORY
CONSUMER
EARTH
UNIT
BAR
L
LINK
Diagram 2: CPC Test (Method 1)
NOTE:
NEUTRAL
CONDUCTOR
OMITTED FOR
CLARITY
ACCESSORY
LONG
CONSUMER
TEST LEAD
UNIT
L
EARTH
BAR
LINK
T
Diagram 3: CPC Test (Method 2)
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