Step 3
Where the CPC wired ring, for example where twin and earth cables
or plastic conduit used wire the ring, temporarily join the live and
CPCs together shown Fig. Neon lamps, capacitors and electronic circuits
L1 N2
L2
L1
N2
N1
E2
E1
Ohm-
meter
FIGURE 14.69
Step test: connection mains conductors and
test circuit conditions.
3 Testing insulation resistance (612. The test should be
made the consumer’s unit with the mains switch off, all fuses place
and all switches closed. Record the results installation schedule such that given in
Appendix the IEE Regulations table such that shown Table
14.13. This value equal for the
circuit. The step value should equal (r1 r2)/4, where r1
and are the ohmmeter readings from step this test (see Table 14. The read-
ings obtained should substantially the same provided that there are no
breaks multiple loops the ring.3)
The object the test verify that the quality the insulation sat-
isfactory and has not deteriorated short circuited.
Sockets connected spur will have slightly higher value resistance
because they are fed only one cable, while each socket the ring fed by
two cables.69. ohmmeter reading should then be
taken between live and earth every socket outlet the ring.
L1 N2
L2
L1
N2
N1
E2
E1
Ohm-
meter
FIGURE 14.68
Step test: connection mains conductors and
test circuit conditions. Record the results table such that shown Table 14.13.13).Electrical installations and wiring systems
355
half the live and neutral ohmmeter readings measured step this test.
. 14
