Bathroom Electrics

[dabaldie]

Don't tell building control (whats part P? ) but I have just installed a new 10.8kw shower in my bathroom.
I have connected from the Hager consumer unit using 10mm cable to a 50A MCB. The consumer unit has no RCD protection, just a 100A contact switch.
I would like to add RCD protection and know that you can buy additional consumer (shower) boxes which incorporate RCD's and 2 MCB's, and was just going to install that. However the other half has just bought a whirlpool bath and i need to protect that too. Initially i was going to connect that to the socket ring main that runs through the floor nearby as it only draws 3A.
Can I connect the new shower RCD unit to the main consumer unit and then connect the ring main and shower to the RCD? or would it be better to run a cable from the new RCD box,through the second MCB to the bath (but i thought the shower MUST be on a seperate spur from the consumer unit)
Or....
should i buy an RCBO for the shower and an RCBO for the socket ring circuit?

or...
should i replace the Contact breaker with an RCD type breaker?

now bear in mind that i have no free spaces on the board to replace MCB's with RCD's..


or... should i just buy a new bigger consumer unit with space to use RCD's?
... or is there something i have missed out?

as you might be able to tell i have done some research.. and am not afraid of electrics, just not sure of the best way forward

 

[Steve]

The quickest and cheapest option is to Buy a new 2-way RCD protected consumer unit, rated 63A (the one you mentioned there), fit a 50A MCB in the old CU and run 10mm T+E or SWA between them, then install the 50A MCB in the new CU for the shower and a 20A MCB for the bath, with 2.5mmT+E to a FCU outside the bathroom.

Alternatively, and the option that would look best, is a full consumer unit change, this would add more potential for expansion too.

If you have a modern consumer unit, have you considered RCBOs, which are an MCB and an RCD in one fuseway in the CU. These can be fitted to nearly any modern consumer unit. Just an idea.

 

[dabaldie]

Thanks Crafty,
I thought about RCBO's but they are £44 each for the hagen unit. That would make £88 as against £35 for the mini consumer unit and MCB
Are they that much better?

 

[dabaldie]

FCU
outside bathroom? is that a switch?

 

[andy]

FCU
outside bathroom? is that a switch?

fused switch

 

[andy]

Thanks Crafty,
I thought about RCBO's but they are £44 each for the hagen unit. That would make £88 as against £35 for the mini consumer unit and MCB
Are they that much better?

RCBO's are smaller (1 way compared to 2 ways for standard). you can go with the RCD and MCB instead of RCBO

 

[Steve]

Aye, they aren't cheap by any stretch of the imagination! maybe thats why they aren't very popular?

 

[plugwash]

rcbos are not popular on domestic but from what i can gather very common in commercial installs.

3 phase split load boards exist but are rare and expensive. also in a commercial environment due to safety rules etc if something trips in a DB you have to get the right person to reset it do you really wan't a whole DB (or the rcd protected half in the case of a split load) tripping out in that situation?!

so your choices are seperate rcds (the uni seem to like to use theese in labs with a rcd on each bench or so) rcbos or rcd sockets none of which are exactly cheap options.

rcd only boards and split loaders are cheap **** that are only generally put up with in extrememly price sensitive markets.

hell i recently saw a large new 3 phase board going in at uni and it was almost totally full of rcbos.

p.s. they didn't seem to be bothering to mark the wires alphanumerically despite the fact that there was a mix of color codes in there (the incoming swa cable and the outgoing wires that were in the massive the board but not yet connected was new code but the rcbo neutral tails were all black!)