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

plug. The permanent connection to the fixed wiring may be by
means of a flexible cable, or
(ii) a monitoring system to BS4444 may be installed which, in the event
of a discontinuity in the protective conductor, automatically
disconnects the supply by a residual current device complying with
relevant recognised standards and having the characteristic specified
in Code 11J or an overcurrent protective device described in Code 9.
(e) For a final circuit supplying a number of socket outlets in a location
intended to accommodate several items of equipment, where it is known
or is reasonably to be expected that the total earth leakage current in
normal service will exceed 10 mA, the circuit should be provided with a
high integrity protective connection complying with one or more of the
arrangements described in paragraph ( f )(i) to ( f )(vi) of this Code.
Alternatively a ring circuit may be used to supply a number of single
socket outlets. There should be no spur from the ring and the supply
ends of the protective conductor ring should be separately connected at
the distribution board. The minimum size of the ring protective earth
conductor should be 1.5 mm 2 .
(f ) The fixed wiring of every final circuit intended to supply an item of
stationary equipment having an earth leakage current exceeding 10 mA
in normal service should be provided with a high integrity protective
connection complying with one or more of the arrangements described
below:
(i) a single protective conductor with a cross-sectional area of not less
than 10 mm 2 ;
(ii) separate duplicated protective conductors, having independent
connections complying with Code 25D, each having a cross-sectional
area not less than 4 mm 2 ;
(iii) duplicate protective conductors incorporated in a multicore cable
together with the live conductors of the circuit, provided that the
total cross-sectional area of all the conductors of the cable is not less
than 10 mm 2 . One of the protective conductors may be formed by a
metallic armour, sheath or braid incorporated in the construction of
the cable and complying with Code 11C;
(iv) duplicate protective conductors formed by metal conduit, trunking
or ducting complying with Code 11C, and by a conductor having a
cross-sectional area not less than 2.5 mm 2 installed in the same
enclosure and connected in parallel with it;
(v) an earth monitoring device which, in the event of a discontinuity in
the protective conductor, automatically disconnects the supply of the
equipment;
(vi) connection of the equipment to the supply by means of a doublewound
transformer or other unit in which the input and output
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