DIY Doctor UK DIY Forums

I plan to change my electric shower unit which was in the house when I moved in approx 15 years ago to a 9.5 kw new model.

The cable is 10mm and the cable run is about 15 metres with a 45 amp double pole neon wall plate switch.

The supply fuse is 100 amps, the consumer unit is an 8 way Wilex with renewable wire fuses, and rated at 100 amps.

At present the shower circuit is only protected by a 40 amp MCB which is plugged into the fuse holder.

Do all these figures look ok and will not cause any problems with the 9.5 shower.

I plan to fit a 30mA RCD as recommended, is it just fitted inline across the live and neutral of the shower cable leaving the plugin MCB in place in the fuse holder
(in effect making it a RCBO)

Also is it advisable or permissable to fit plug in MCB's to protect the other circuits.

Any comments would be appreciated. Cheers.

Hi, it all seems fine, the plugged in mcb will be a type 2 which is the only ones available to fit the wylex boards, with the load & distance quoted I can't see a problem.
As for RCD, yes effectively you fit in line with L & N and if fitted in a good enclosure there will be some where to terminate the earths
regards SPARX

Thanks sparx, much appreciated.

You can't put a cost on safety so if I protected all the other circuits with plugin mcb's would the CU support it ok without tripping.

Cheers

MCB's act quicker on overload and slower on short circuit than fuses if you change all fuses for MCB's you may find on the odd occasion the MCB will trip when light bulbs blow. But since they can easy be reset overall I would say it would be a good thing to replace all fuses with MCB's I did and never regretted it.

Thanks ericmark, I will do that then I know the electrics are upgraded satisfactorily.

Damoman