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

(2) Basic protection and fault protection
Where protection by the use of SELV or functional extra low voltage
(FELV) is used, the voltage should not exceed 25V a.c., r.m.s. or 60V
ripple free d.c. and, regardless of the voltage, basic protection should be
provided by:
(a) a barrier or enclosure affording at least the degree of protection
IP2X or IPXXB or equivalent, or
(b) insulation capable of withstanding a test voltage of 500V d.c. for 60
seconds.
(3) Basic protection
Protection by obstacles or placing out of reach is not permitted.
(4) Fault protection
(a) Fault protection should be provided by one of the following:
(i) SELV,
(ii) automatic disconnection, a supplementary equipotential
bonding conductor should be provided and be connected to the
exposed conductive parts of the fixed equipment and the
conductive parts of the location,
(iii) electrical separation, in which case only one socket or piece of
equipment should be connected to each secondary winding of
the isolating transformer, or
(iv) the use of Class II equipment adequately protected to an IP
code (see IEC 60529) in which case the circuit should be further
protected by a residual current device having the characteristics
specified in Code 11J.
(b) A supply to or a socket intended to supply a hand lamp should be
protected by SELV.
(c) If a functional earth is required for certain equipment, for example
measurement or control apparatus, equipotential bonding should be
provided between all exposed conductive parts, all extraneous
conductive parts inside the restrictive conductive location, and the
functional earth.
(d ) A supply to or a socket intended to supply a handheld tool should be
protected by SELV or electrical separation.
(e) A supply to fixed equipment should be protected by one of the
methods listed in subparagraph (a) above.
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