Shower replacement

[Bobzilla]

Hi all

I would describe myself as relatively competent, and I am looking to replace my electric shower. I do not know what wattage my existing shower is, but I have bought a 10.5Kw shower to replace it with.

As I understand it, in order to run a 10.5kw shower, I will need a suitable MCB on the circuit and 10mm wire to feed it.

I have a few questions:

1) If the existing shower is only 8.5kw, but the wiring is 10mm, does this count as direct replacement for Part P purposes?

2) The current draw on a 10.5kw shower should be 45.6A. Do I need a 45A or a 50A MCB? Can I fit this under Part P, or would that require electrician/inspection?

3) If the wiring is 6mm, what is the largest shower I can run off this?

4) Would it be cheaper to get someone in to do the work or get the inspection if Part P covers the work? I am in Alton, Hampshire.

5) I presume I can get a reasonable idea of the circuitry by looking at the existing MCB, but I guess I shouldn't rely on this as conclusive - there are enough cowboys out there to make this a bad idea, yes? Even where a new consumer unit was installed professionally post 2005?

 

[PrenticeBoyofDerry]

You need your circuit breaker to be higher than the output current of the shower,
10mm cable will carry 53A
6mm cable 40A
your breaker size can not exceed that of the current carrying capacity of the cable.
Fitting a new MCB is notifiable
Notifable work will be charged at about 135 GBP.
plus the cost of your materials and time.
I'd go with ringing a quailified electrician up.