Residual current devices (RCDs)
Your electrical installation may incorporate one or more RCDs. An
RCD is an automatic safety device intended to provide extra protection against
electric shock. The national safety standard has for some years required
any socket-outlet that may be used to supply portable electrical equipment
outdoors, such as lawnmowers or electric drills, to be protected by an RCD with
a rated tripping current not exceeding 30 mA.
Where a fixed RCD has been installed (such as in the consumer unit or a
socket-outlet), there should be an adjacent notice that reads :
This installation, or part of it, is protected
by a device which automatically switches off the supply if an earth fault
develops. Test every three months by pressing the button marked 'T' or
'Test'. The device should switch off the supply and should then be
switched on to restore the supply. If the device does not switch off the
supply when the button is pressed, seek specialist advice.
It is important that every RCD is regularly tested in accordance with this
recommendation.
