RCD MCB queries

alphaomegalife · Posted: Tue Jul 06, 2004 11:09 am Post Subject: RCD MCB queries

Hi there I have an old style fuse box with the fuses replaced with RCDs, the box has used all of the available slots for fuses however I am trying to install a shower. What do I need to buy to solve my problem a RCD or a MCB. I presume that an auxilliary unit will be needed but which type, my intended shower will be an 8.5kv

dingbat · Posted: Tue Jul 06, 2004 11:30 am Post Subject:

You need both an RCD and an MCB. The MCB gives you overload and short circuit protection, the RCD gives you supplementary protection against electric shock. You can get these combined in a purpose-made 'shower consumer unit'.

But it's not so straightforward as that. From the installation you've described (They're MCB's by the way, not RCD's) it's a pretty fair bet that you have no supplementary bonding in your bathroom and quite probably insufficient equipotential bonding and earthing.

Bathrooms are considered special locations as far as the wiring regulations are concerned and, as such (considering you didn't know the difference between an RCD and an MCB) a new shower install is beyond the average DIY-er.

This topic has been covered stacks of time in the past on this site - try a search - but I'd still recommend you call in a professional.

alphaomegalife · Posted: Tue Jul 06, 2004 11:41 am Post Subject:

Thanks for your prompt reply,

I am getting a clearer picture that I should probably be calling in a qualilfied sparky

dingbat · Posted: Tue Jul 06, 2004 11:57 am Post Subject:

Give this a quick read-over:

http://www.diydoctor.org.uk/projects/electricshower.htm