Code of Practice for the Electricity (Wiring) Regulations - 2009 Edition

(d ) Secondary Injection Test
(i) The overload and fault current protection characteristics of
protection relays should be verified with secondary injection
test.
(ii) The test should be carried out by injecting a.c. of different
magnitudes into the relay terminals and measuring the relay
operating time. The operating time should be checked against
the manufacturer’s data sheet.
(10) Additional checks for installations in hazardous environment
The following additional checks, where appropriate, should be carried
out for installations in hazardous environment:
(a) Where appropriate, the area involved should be checked to ensure
‘gas free’ condition before insulation and earth fault loop impedance
test are carried out.
(b) All equipment should be suitably protected according to the types of
protection under Code 15. The integrity of the type of protection
provided for the equipment should not be jeopardised by the
method of installation. No alteration that may invalidate the
conditions of protection can be used.
(c) Equipment should be kept clean and free from accumulation of dust,
foreign particles and deleterious substances. Equipment is kept free
from condensation.
(d ) All lamps, fuses and replaceable parts should be checked so that
correct rating and types are being used.
(e) The surface temperature of all equipment should be appropriate to
the type of protection being provided.
21C Inspection of High Voltage (H.V.) Installations
Inspection of H.V. installations should follow those for L.V. installations listed
in Code 21A with additional checks on the following items where relevant:
(a) provision of suitable locking facilities for every entry to an H.V.
switchroom/substation;
(b) continuity of protective conductors especially the bonding of all exposed
conductive parts; and
(c) provision of padlock facilities for shutters, key boxes etc.
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