Shower cable

[tidge65]

Hi All, would 6mm cable on a 9 metre run using a 40 amp mcb, be sufficient for a 8.5kw shower? The consumer unit has a built in rcd. The cable is only buried in the wall for 2.5 ft, the rest is uncovered. (under bath and in the loft space not covered by insulation)

 

[Aardvark Avo]

These are given directly from quote from books, as such I take no liability:-
8500/230 =37 amps
with reference to the electricians guide to building control
up to 7.2 kw =6mm
upto 9.6 kw =10mm

BS7671
method 2(buried in wall P210 same as method 1 current capacity)
If you also go by bs7671 regs p220 method 1, max cap 6mm 47 amps


my choice would be 10mm as I have guessed how cable is buried and if the cable was in thermally insulating wall only 34 Amps rated.
******Legally part p it should be fitted by registered installer*******
please understand I wish to cover myself while still answering your question

 

[Steve]

******Legally part p it should be fitted by registered installer*******

State where in any official documents it says this.

(Clue: it doesn't. Anywhere.)

The OP may legally DIY as long as he notifys his building control dept who will charge a fee and inspect and test his work!