cable size

[Matheous]

Cable (mm2) size please to run a 9.5 kw electric shower.

Thanking you in anticipation.....

[ChuckFickens]

the qualified sparky thats installing it for you will know.

[New Judge]

The shower will be drawing about 40 amps and 10mm cable will be necessary.

As ChuckFickens intimates, the work should be carried out by a certified installer. From January 1st 2005, all significant electrical work in homes across England and Wales have to be carried out by a registered installer, or approved and certified by the local authority's building control department.

[ChuckFickens]

Hence why I didn't say 10mm.

[buildersmate]

The alternative is to make a Building Control application yourself, if you wish to use a person who is not authorised in the manner CF indicates.

[Matheous]

Thank you guys......I just want to establish whether we can use existing wiring for a new shower....

[New Judge]

39.58 amps at 240 volts,knobby, but we'll not quibble over 0.42 of an amp!

[Matheous]

Just to add another question.....I have checked our RCD and noticed it rated at 40amps. Is that adequate enough and probably not going to be troublesome??

[matt1e]

new judge and knobby you have your maths wrong
if it is new it will be rated 9.5 kw at 230V
at 230V it will draw 41.3
at 240V it will draw 43.08
if it is an older unit rated 9.5kw 240V then you are correct

[cogsy]

what about the voltage drop on the length of the cable might need a bigger mcb than 40 amp