can i use a 9.5kw shower

[sturobs]

Hi, I’m looking to get a new electric shower and have a few questions that I need help on.
I have a wylex board that currently has 3x NB05 5A type2 mcb's and 3x NB30 30A mcb's. 1x NB30 mcb is currently used for the shower supply.
The board says it has a load capacity of 63amps and has a wyles wsem RCD 100mA, with 63A load.

I presume I’m at my maximum usage on this board and the 9.5kw shower I’ve just ordered is not going to work out as I will need a NB40 40A MCB which I also presume will be too much for the wylex board that I have got.
I don’t want to mess about with any electrics and don’t want to waste money on an electrician until I can know that I got a shower that can be used on the current electrical system.

Thanks in advance for any help.

 

[flameport]

30A = 7kw maximum.
Shower will need a 30mA RCD, so your 100mA RCD is not suitable.

Either have a smaller consumer unit fitted for the shower only, or replace the existing one completely.

 

[sturobs]

thanks for your help

 

[streetlighter]

Looks like you will need to install a 7Kw shower then quite hard to source these days. And fit a 30mA RCD into the shower circuit as this will be in the instructions and also required by the regs.
What size is the cable for existing shower 6mm ?

 

[sturobs]

i'm pretty sure there's a 10mm cable, would a 7.5kw shower be ok?

 

[securespark]

Probably 4milli, if it's the same age as that board.....

 

[sturobs]

thanks for help all, would i be able to use a 7.5kw shower do you think? just that they are more available or will this be out of regs again?
cheers

 

[PrenticeBoyofDerry]

The 7.5kW shower will require 32A if you board is carrying the old type breakers 30A it's borderline but should function without tripping.
But would refer to manufacturers instruction prior to buying it.
4.00mm2 twin and earth cable will carry a maximum of 37A, providing the route of the cable is not within insulation and not run in conduit or trunking.
There should not be any voltage drop issues either, providing the cable length does not exceed 32 metres.
But you will require a 30mA RCD.
So it may be advisable to consider installing a shower protection unit, that is installed external of your board, this will then allow you to have both RCD protection and MCB protection, some will have a RCBO that offers both on an individual device.
This could also allow a higher output of shower cable size allowing!