Last month, we indicated that a common trend in terms of trade test failures is centred round the non-isolation of control circuits despite the fact that the main circuit has been isolated. The purpose of the mains isolator is to isolate the total circuit, both the incoming feeder line (single phase or 3-phase) as well as the control circuit. If the mains isolator is off and the control circuit can still be activated, the candidate will fail. This month we look at what seems to be less lethal initially, but can have severe consequences for the electrician. The purpose of earthing an installation is to guard every electrical installation and appliance against the effects of leakage currents, static charges and lightning discharges… (more)

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