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

(c) Zone 3 is the volume outside Zone 1, limited by the cold side of the
thermal insulation of the ceiling and walls and a horizontal surface
located 1.0m above the floor.
(3) Basic protection and fault protection
(a) The protective measures of obstacles and placing out of reach are
not permitted.
(b) The protective measures of non-conducting locations and earth-free
local equipotential bonding are not permitted.
(c) Additional protection should be provided for all circuits of the sauna,
by the use of one or more RCDs having the characteristics specified
in Code 11J. RCD protection need not be provided for the sauna
heater unless such protection is recommended by the manufacturer.
(d ) Where SELV or PELV is used, whatever the nominal voltage, basic
protection should be provided by:
(i) basic insulation of live parts such that they are completely
covered with insulation which can only be removed by
destruction, or
(ii) barriers or enclosures affording a degree of protection of at
least IPXXB or IP2X.
(4) Selection and erection of equipment
(a) All equipment should have at least the degree of protection of IPX4.
If cleaning by use of water jets may be reasonably expected,
electrical equipment should have a degree of protection of at least
IPX5.
(b) In Zone 1, only the sauna heater and equipment belonging to the
sauna heater should be installed.
In Zone 2, there is no special requirement concerning heat resistance
of equipment.
In Zone 3, equipment should withstand a minimum temperature of
125°C and the insulation and sheaths of cables should withstand a
minimum temperature of 170°C.
(c) The wiring system should be preferably installed outside the zones,
i.e. on the cold side of the thermal insulation. If the wiring system
is installed on the warm side of the thermal insulation in Zones 1 or
3, it should be heat-resisting. Metallic sheaths and metallic conduits
should not be accessible in normal use.
(d ) Switchgear and controlgear which forms part of the sauna heater
equipment or of other fixed equipment installed in Zone 2 may be
installed within the sauna room or cabin in accordance with the
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