Wiring for electric shower

[newoilman]

Hi all,
I have been asked to replace an electric shower (Redring Actice 300 7.2KW) with something more powerful.
I have no knowledge of electrics and would like to know what higher KW ratings do for a shower and would the wiring on the current unit be safe if a 8.5KW shower was fitted?
Thank you in advance

 

[bongos]

On a 230V supply, a 7.2KW shower would draw around 32Amps. An 8.5KW shower would draw around 37Amps.

A higher KW shower could mean that you need to upgrade the size of the cable providing power for it and also possibly the fuse/MCB protecting it. The cable size will depend on the cable run (whether covered by insulation etc) and also the length (due to voltage drop). These factors could mean you need to uprate the size of your cable, most commonly from 6mm to 10mm t+e.

You also have to take account of the fuse/MCB protecting the existing circuit. It may be that the existing setup is unable to provide the extra power safely as it could mean you are drawing too much current through a fuse box unable to provide it. There are plenty of pics on this site of the results of people upping a fuse to 45A to supply the correct cable size but in a setup where only 30A is designed to be supplied by the fusebox.

I believe that it is also necessary to protect the shower with a 30mA RCD.

But i'm no spark! I'm sure someone else will be able to confirm whats necessary

 

[ban-all-sheds]

An RCD is not required, but it is a Very Good Idea™.

Hi all,
I have been asked to replace an electric shower (Redring Actice 300 7.2KW) with something more powerful.

Asked by whom, and on what basis?

I have no knowledge of electrics and would like to know what higher KW ratings do for a shower and would the wiring on the current unit be safe if a 8.5KW shower was fitted?
Thank you in advance

Last part first - we have no way of knowing.

Second part next - if a more powerful one is wanted, i.e. the current 7.2kW has been found to be inadequate (no surprise) I would strongly advise 10kW+.

And finally "I have no knowledge of electrics".

Should you therefore be doing this, and do you have knowledge of the Building Regulations?