Note: Special precautions
and provisions may be necessary for current measurement in CT secondary
circuits and such measurement techniques are outside the scope of the guidance
in this document.
Where current
measurements are to be made using instruments other than insulated tong-test
type instruments, the connections should be made with the apparatus dead, and
should be made secure before the power is switched on. Any such temporary
connections need to be adequately rated both for current and voltage.
If regular testing
needs to be done, for example on complex control panels, nearby bare live
conductors should not be accessible (eg screened) where access is not required.
Alternatively, purpose-made screened test points or instrumentation may be
provided.
Examination of
equipment
All items of test
equipment, including those items issued on a personal basis, should receive a
regular inspection and, where necessary, a test by a competent person. Records
are recommended to be kept of inspection and testing of the equipment,
particularly where faults are found. These records will help decide how often
visual inspection or testing will need to be carried out. It is important that
electricians are aware of the kinds of defect which may occur in test
equipment. Examples of common faults are:
(a) Cracked meter
cases;
(b) Damaged
insulation (abrasion, cuts or perishing of flexible insulation);
(c) Loose terminals.
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