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

etween the base and the inside walls of the box or enclosure is not
less than 6 mm.
(ii) There should be no live metal protruding from or flush with the
socket outlet base. Any exposed live metal part should be recessed
at least 2.5 mm from the base surface.
(iii) Where it is intended that the fixed wiring conductors pass through
holes in the base of the socket outlet to the terminals, the minimum
diameter of each hole should not be less than 9.5 mm.
(4) Construction of terminals
(a) Line and neutral terminals in the socket outlet should permit the
connection, without special preparation, of one, two or three 2.5 mm2 solid or stranded or of one or two 4 mm2 stranded conductors.
(b) Earthing terminals should permit the connection without special
preparation, of one, two or three 1.5 mm2 or 2.5 mm2 solid or stranded
or of one or two 4 mm2 stranded conductors.
(c) Where pillar terminals are used they should have clamping screws of
sufficient length to extend to the far side of the conductor hole. The end
of the screw should be slightly rounded so as to minimize damage to the
conductors. The sizes of the conductor hole and the clamping screw
should be such that the clearance between the sides of the major
diameter of the clamping screw and the conductor hole does not exceed
0.6 mm. The size of conductor hole should not be less than 4.3 mm.
(d ) Terminal screws should have a nominal diameter of not less than 3 mm.
(5) Screws and connections
(a) Screwed connections, electrical and otherwise should withstand the
mechanical stresses occurring in normal use. Screws transmitting
electrical contact pressure should screw into metal.
(b) Screws should not be of insulating material if their replacement by a
metal screw would affect the safety or performance requirements of the
accessory.
(c) Where current carrying parts are screwed together, the current path
should not rely on the screw threads.
(6) Creepage distances, clearances and distances through
insulation
(a) When the socket outlet is correctly assembled and wired with the
appropriate cable, the minimum clearance through air and the minimum
creepage distance shall be 2.5 mm:
(i) between live parts of opposite polarity;
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