RCD's

[Tom JE]

Hi chaps,

I am in the process of fitting a new shower on the existing shower circuit. I am replacing the shower with one of the same kw rating. Our consumer box is quite old and has rewirable fuses. I would like to swap the shower fuse with an MCB and also fit an RCD. I have only seen MCB's that fit where the fuses go but not RCD's. I can afford to replaced the consumer unit right now but would like an RCD. Is there any other way of doing this?

Cheers

Tom

 

[dingbat]

There are a number of very good reasons why you shouldn't be supplying your shower from your existing rewireable fuseboard. And only one of them is that you cannot get such a thing as a plug-in RCBO for such boards.

The correct way is to split the supply tails in a Henley block and fit a dedicated shower consumer unit with RCD and appropriate MCB for the size of the cable, which will also affect the rating of shower unit you can install.

You will have to make sure that your earthing and bonding arrangements are satisfactory, especially the supplementary bonding in the bathroom.

This work is also notifiable to local authority building control, for a fee.

 

[Tom JE]

Cheers for the reply pal. I'll look into getting that done asap!

 

[Tom JE]

Sorry to keep harping on about this, but i'm confused now. On the shower box it says that an RCD is not essential for an electric shower - just an MCB. How is that the case? Surely it makes sense to fit an RCD. I would like to get one fitted but would it be a big deal if i didnt as the instructions seems to suggest?

 

[dingbat]

It makes perfect sense to fit the RCD. But as an item of fixed equipment the regulations do not require that a shower is RCD protected.

However most manufacturers specify one in their installation advice and few reputable electricians would consider installing without one.

But, in any case, it is highly likely that your rewireable fuseboard is not rated to carry any fuse/MCB above 30/32A and does not have sufficiently large terminals to take the 16sqmm earth conductor that you'll be upgrading to.

Changing the shower unit itself like-for-like may seem pretty straightforward, but to an electrician this is one of the least desirable domestic jobs because most existing installtions fall a long way short of compliance. Try getting some quotes and you'll see what I mean.

 

[Tom JE]

Yeah, i can well believe that mate. Cheers for the advise!