The April 2000 amendments to BS7671
(AMD 10983) have changed all of the Regulations relating
to bath and shower rooms. Although the principles remain
the same, much of the detail has been altered. For example,
bath and shower rooms have now been split into zones, as
was previously the case only for swimming pools and saunas.
The amended regulations Section 601 may be used at once,
but must be used for all installations after January 1st,
2002.
Up to that time either
set of Regulations may be applied, but whichever is chosen
must be used in its entirety. It is not permitted to mix
the two versions of Section 601.
click here for amended Introduction.
7.2.1 - Introduction - prior to January 1st, 2002
People using a bathroom are often unclothed
and wet. The absence of clothing (particularly shoes) will
remove much of their protection from shock (see{3.4}),
whilst the water on their skin will tend to short circuit
its natural protection. Thus, such people are very vulnerable
to electric shock due to their reduced body resistance,
so special measures are needed to ensure that the possibility
of contact (either direct or indirect) is much reduced.
Guidance Note 7 (Special Locations) provides data on the
impedance of the human body. However, the figures are complicated
by the fact that values differ significantly from person
to person; it would be sensible to assume a worst case possibility
which suggests that the impedance of the human body from
hand to foot is as low as 500 Ohms. Since this calculates
to a body current of 460 mA at 230 V, we are considering
a fatal shock situation. When the fact that the impedance
figures assume a dry body are taken into account and may
be halved for wet people, we come to a shock current approaching
I A! Attention is drawn to the fact that a bath used for
medical treatment may need special consideration, because
the possible hazard is greater.
Appliances and sockets for use in these
high-risk areas must be separated extra-low voltage (SELV)
type, at a potential not exceeding 12 V; the exception is
a shaver unit fed from a double wound transformer to BS
EN 60742
(see {5.8.4}). Such equipment must be protected to level
IP2X, which means that it must be impossible to touch live
parts with a finger, and must have insulation capable of
withstanding a voltage level of 500 V r.m,s. for one minute.
Such socket outlets, or fused connection units in a bathroom
or a bedroom containing a shower cubicle, must be protected
by an RCD with an operating current no greater than 30 mA,
The special requirements of this section
do not apply to rooms (such as bedrooms) containing an enclosed
and prefabricated shower basin, provided that switches are
not mounted within 0.6 m or sockets within 2.5 m of the
door opening as indicated in {Fig
7.1}.
7.2.1 Introduction - (after January 1st, 2002)
People using a bathroom are often unclothed
and wet. The absence of clothing (particularly shoes) will
remove much of their protection from shock (see
(3.4)), whilst the water on their skin will tend to
short- circuit its natural protection. Thus, such people
are very vulnerable to electric shock due to their reduced
body resistance, so special measures are needed to ensure
that the possibility of contact (either direct or indirect)
is much reduced. Guidance note 7 (Special Locations) provides
data on the impedance of the human body. However, the figures
are complicated by the fact that values differ significantly
from person to person; it would be sensible to assume a
worst case possibility which suggests the impedance of the
human body from hand to foot is as low as 500 ohms. Since
this calculates to a body current of 460mA at 230V we are
considering a fatal shock situation. When the fact that
the impedance values assume a dry body are taken into account
and may be halved for wet people, we come to a shock current
approaching 1 A! Attention is drawn to the fact that a bath
used for medical treatment or for disabled people may need
special consideration, because the possible hazard is greater.
The special requirements of this section do not apply to
rooms (such as bedrooms) containing an enclosed and prefabricated
shower basin, provided that switches are not mounted within
0.6m or sockets within 2.4m of the shower door opening as
indicated in (Fig
7.1a) All socket outlets in such rooms must be protected
by an RCD with a rating no higher than 30mA. The special
requirements do not apply to emergency facilities in industrial
areas and laboratories. Fig
7.1a) Permissible positions of switches and socket outlets
in a room containing a shower cubicle but no bath.