Providing the first five tests were satisfactory, the supply may now be
switched and the final tests completed with the supply connected. The
test made with the supply switched on, and carried out from the furthest
point every final circuit, including lighting, socket outlets and any fixed
appliances.
7 Testing earth fault loop impedance (supply connected)
(612.
Test from the common terminal switches earth, the live pin each
socket outlet earth and the centre pin any Edison screw lampholders
to earth.6 and should fault occur.9)
The object this test verify that the impedance the whole earth
fault current loop line earth low enough allow the overcurrent pro-
tective device operate within the disconnection time requirements of
Regulations 411. Switch off the consumer’s unit isolate the installation. each case the voltmeter test lamp should indicate the supply
voltage for satisfactory result.
The IEE Guidance Note tells that acceptable value for the measure-
ment the earth electrode resistance will about 200 less.
.
Record the result schedule test results such that given in
Appendix the IEE Regulations. Using line earth loop impedance tester, test between the incoming
line conductor and the earth electrode. Disconnect the installation protective equipotential bonding from
the earth electrode ensure that the test current passes only
through the earth electrode.Basic Electrical Installation Work
358
To verify the resistance electrode used this way, the following test
method may applied:
1.
4. Record the results schedule test results. Reconnect the protective bonding conductors when the test is
completed.4.
3.2.
The test will, most cases, done with purpose-made line earth loop
impedance tester which circulates current excess 10A around the
loop for very short time, reducing the danger faulty circuit.
The whole earth fault current loop examined this test comprised all
the installation protective conductors, the protective earthing terminal and
protective conductors, the earthed neutral point and the secondary wind-
ing the supply transformer and the line conductor from the transformer
to the point the fault the installation.
2.
6 Testing polarity: Supply connected
Using approved voltmeter test lamp and probes which comply with
the HSE Guidance Note GS38, again carry out polarity test verify that
all fuses, circuit breakers and switches are connected the live conductor.2 and 411.3
