12
2.
The appliance
must be earthed
by connecting the supply-cable earth conductor to
the earth terminal.
Supplementary bonding:
Within the bathroom or shower room, all accessible
conductive parts of electrical equipment and extraneous conductive parts that are
likely to introduce earth potential, must be electrically bonded to earth using a
minimum cable size of 4.0 mm
2
if the cable is not mechanically protected (2.5 mm
2
if mechanically protected).
3.
The minimum cable size (cross-sectional area) required is 6 mm
2
under normal
conditions of installation.
Important!
The shower circuit should be separated from other circuits by at least
twice the diameter of the cable or conduit and it should not be run through thermally
insulating material or in locations where the ambient temperature is likely to exceed
30 °C. If any of these conditions are unavoidable it is necessary to determine the
cable size which will prevent damage to the cable caused by overheating.
4.
To obtain full advantage of the power provided by this unit, use the shortest possible
cable route from the consumer unit to the shower. It is also necessary to satisfy the
disconnection time and thermal constraints which mean that, for any given
combination of current demand, voltage drop and cable size, there is a maximum
permissible length of circuit.
As a guide only
, the following maximum permissible lengths are given for 6 mm
2
cable protected by a 40A MCB type B and allowing for a 5 volt drop:
Essentials 7.5 kW (240 V AC) at 240 V - 22 Metres
Essentials 8.5 kW (240 V AC) at 240 V - 19 Metres
Essentials 9.5 kW (240 V AC) at 240 V - 18 Metres
5.
A 30 mA residual current device (RCD) should be fitted. This may be part of the
consumer unit or a separate unit.
6.
A separate, permanently connected supply must be taken from the consumer unit
to the appliance through a double-pole switch, which has at least
3 mm contact separation. The switch can be a ceiling mounted pull-cord type within
the shower room or a wall mounted switch in an adjacent room. Suitable ceiling
mounted pull-cord switches for Essentials electric showers include:
Make
Model Rating
Volex
VX9706
40 Amp
Crabtree
2167
40 Amp
MK
3164 WHI
45 Amp
Ashley
CS445N
45 Amp
Tenby
CS7545
45 Amp
