mcb trips out?

When I first installed electric showers some 25 years ago the typical rating would have been in the region of 6-7 Kw. These days it's more likely that the rating is 9Kw +. If you have installed your new shower using and existing circuit it is very likely that the cable is underrated. It seems to me that you are exceeding the current of the circuit which is very dangerous as overloaded electrical circuits cause fires! Please get your electrical system checked out by a qualified electrician before it's too late.

MikeW

MikeW
March 2008

Shower also needs to be protected by a separate 30 mA/40A RCBO or else a 30 mA RCD with the 40A mcb.

J
March 2008

your cable is more likely under sized as well

andy
March 2008

The mcb needs to be of a current rating suitable for your shower, which will take 38 amps at 250v. The nearest size is therefore 40 amp.

John
March 2008