Bathroom RCD protection query

Geoff_W

I have, adjacent to the bathroom, an RCD device which protects the bathroom lights, fan and pumped shower. This was originally installed because I had an old, fused consumer unit. My consumer unit has now been replaced with a new one containing MCB's. My question is: do I still need the original RCD to protect the bathroom circuits? Incidentally, when I test the RCD it also trips the power circuit MCB in the consumer unit.

Risteard

Geoff_W wrote: »

I have, adjacent to the bathroom, an RCD device which protects the bathroom lights, fan and pumped shower. This was originally installed because I had an old, fused consumer unit. My consumer unit has now been replaced with a new one containing MCB's. My question is: do I still need the original RCD to protect the bathroom circuits? Incidentally, when I test the RCD it also trips the power circuit MCB in the consumer unit.

Presumably it's either an RCBO or RCCB tripping and not a circuit breaker (previously known as an MCB)?

Geoff_W

Thanks for your reply. Not quite sure of the difference between the different types of breaker, so I was going to include pictures of the items but I can't work out how to do that within this post.

Belenus

Host your picture or pictures here, select 'Hotlink for forums' and paste the link or links in your post.

Geoff_W

Thanks @Belenus

Here are the pictures...

Owain_Moneysaver

Geoff_W wrote: »

do I still need the original RCD to protect the bathroom circuits?

You do if the bathroom circuits are not protected by an RCD on the main consumer unit - which we can't see.

Note that RCD is also a fused connection unit. The bathroom lights/fan/pump are almost certainly spurred off the adjacent socket and so a fused connection unit would still be required, even if an RCD wasn't.

The kitchen lights (both sets) should also be fused down on a fused connection unit somewhere as they appear to be connected to 32A and 20A socket circuits - what a mess.

Geoff_W

The kitchen lights referred to on the consumer unit are not the main lights but under-cupboard LED lights, and they do have a local switch fused spur. Perhaps this picture might help?

Owain_Moneysaver

Geoff_W wrote: »

The kitchen lights referred to on the consumer unit are not the main lights but under-cupboard LED lights, and they do have a local switch fused spur. Perhaps this picture might help?

It now works.

It looks like all circuits (except the alarm) are on either an RCD or an RCBO, so you should be able to remove the RCD/FCU next to the socket and replace it with a FCU.

Ectophile

That looks like a modern twin RCD setup. The person who installed it didn't fill in the "circuits protected by RCD" bit. But unless they made a total mess of it, then all circuits with the possible exception of the alarm, should now be on an RCD.


If in doubt, press the yellow test button on the RCD next to the lighting circuit, and see if they go off. You're actually supposed to do that test every 6 months or so, but the vast majority of people never do.


Having 2 RCDs protecting the same circuit doesn't actually do any harm. And it's not unknown for an RCD to fail to trip when it's supposed to.

Geoff_W

Ectophile wrote: »

Having 2 RCDs protecting the same circuit doesn't actually do any harm. And it's not unknown for an RCD to fail to trip when it's supposed to.

Except that when I test the bathroom RCD it also trips the RCD in the consumer unit and removes power to all the socket outlets. I think I'll replace that with an FCU, in that way I can isolate the bathroom without affecting anything else.

Thanks to everyone for your helpful comments.