Triton 10.5kW, Installation And Operating Instructions Manual

9

Electric shower

Table B

Note: 

Cable selection is dependent on 

derating factors

Twin and earth PVC insulated cable

Current carrying capacity

In conduit

trunking

6mm²

38A

10mm²

52A

16mm²

69A

Installed in an 

insulated wall

6mm²

32A

10mm²

43A

16mm²

57A

Clipped direct

or buried in a 
non-insulated 

wall

6mm²

46A

10mm²

63A

16mm²

85A

6mm2

10mm2

16mm2

*The method below may be used by

installers to determine the approximate 

size of the incoming cable.

1.

Measure the width of an individual strand,
and half that measurment to find 

(r)

,

e.g: 

1.34mm ÷ 2 = (r) 0.67mm

2.

Multiply 

(r) x (r)

 x 

3.14,

e.g: 

(r)

0.67 x (r)

0.67 

x 

3.14 = 1.41mm2

3.

Multiply this by the number of wire strands
(usually 7), e.g: 

1.41mm2 x 7 = 9.87mm2.

4.

The number obtained would suggest

10mm2

 wiring.

*PLEASE NOTE:

 If unsure, consult a qualified Electrician.

6

A 45 amp double pole isolating switch with 
a minimum contact gap of 3mm in both 
poles must be incorporated in the circuit.

6.1

  It must have a mechanical indicator showing 

when the switch is in the OFF position, and 
the wiring must be connected to the switch 
without the use of a plug or socket outlet.

6.2

 The switch must be accessible and clearly 

able, but out of reach of a person 

u

xed bath or shower, except for the

cord of a cord operated switch, and should
be placed so that it is not possible to touch
the switch body while standing in a bath or
shower cubicle. It should be readily accessible
to switch off after using the shower.

7

Where shower cubicles are located in any 
rooms other than bathrooms, all socket 
outlets in those rooms must be protected by 
a 30mA RCD.

8

The current carrying capacity of the cable 
must be at least that of the shower circuit 
protection 

(see Table B)

.

8.1

  To obtain full advantage of the power 

provided by the shower, use the shortest 
cable route possible from the consumer unit 
to the shower.

8.2

  It is also necessary to satisfy the disconnection 

time and thermal constraints which means 
that for any given combination of current 
demand, voltage drop and cable size, there is 
a maximum permissible circuit length.

9

The shower circuit should be separated from 
other circuits by at least twice the diameter 
of the cable or conduit.

9.1

  The current rating will be reduced if the 

cabling is bunched with others, surrounded 
by thermal loft or wall insulation or placed 
in areas where the ambient temperature 
is above 30°C. Under these conditions, 
derating factors apply and it is necessary to 
select a larger cable size.

9.2

  In the majority of installations 

(see 

Table B)

, the cable will unavoidably be 

placed in one or more of the above 
conditions. This being so, it is strongly 
recommended to use a minimum of 10mm 
cabling throughout the shower installation.

9.3

  In any event, it is essential that individual 

site conditions are assessed by a competent 
electrician in order to determine the correct 
cable size and permissible circuit length.