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sollysta Wiring Accessories Guide
9
BS 1363 socket-outlets
As previously described basic protection is to provide
protection against electric shock under fault free conditions.
Socket outlets having apertures for plug pins will fulfil the
requirement as the apertures are smaller than that specified
by IPXXB or IP2X. In addition to this they will have a
shutter mechanism that prevents access to live parts unless
the earth pin is also present and has been inserted first.
This however can be either intentionally or inadvertently
defeated by inserting something into the earth pin aperture
first.
For this reason, a designer could specify a manufacture that
uses additional measures so that the shutter mechanism
cannot be inadvertently defeated. They usually require all
three pins to be present and the earth pin to be inserted first
order to gain access
High protective conductor
currents
This situation is covered in regulation 543.7. Protective
conductor currents can be caused by electronic equipment
such as computers printers etc. They can also be caused by
certain luminaires or heating elements however.
This can be a problem for an individual item of equipment
but usually needs to be considered where several items of
equipment, each producing a small amount of protective
conductor current, are connected on the same circuit. If the
accumulated current exceeds 10mA then the requirements of
543.7.1.3 need to be considered.
Of the five options within this regulation, the most common
solution is (iii) where two protective conductors are used.
543.7.1.4 specifies that where this solution is used the two
ends of the protective conductor must be independently
terminated at all connection points throughout the circuit.
“ 3 pin operated shutters are safest ”.