Electrical Question

Rating of rcd

i have a rcd with a rating of 40 amp 30 ma trip is this ok to use with a 7.5 kw shower

5 Answers

Best Answer

If its a BSEN61008 type RCD then although it is rated at 40amps, it has no overcurrent protection so you will also need to use a 32amp or a 40amp BSEN60898 type B MCB as well.

If its a BSEN61009 type RCD (i.e. an RCBO) it will have overcurrent protection built in so an additional MCB is not required.

In terms of the KW rating, 7500w/230v = 32.6amps so a 40amp RCD will be fine on a 7.kw load.

Please remember that any electrical work that you carry out in the bathroom/shiower room or at the mains fusebox position fall under Part P of the building regulations and as such if your doing DIY electrical work you must obtain consent from your local authority bhuilding control department and pay their respective fees. Failure to comply with part p can result in you being fined up to £5000, so if your not aware of the current legal position on DIY electrical works, google Part P or the link below for more information;


Hope this helps please click on "like" if it does

Answered 28th Oct 2012

Electrical Safety Services

Member since 17 Oct 2011

What size cable is installed ?

If the cable size is 6mm squared you will require a 32a device.
Any size over 6 then the 40a is ok

Answered 28th Oct 2012

Durham Electrics

Member since 1 Aug 2012

yes providing that the circuit is designated for the shower only and not part of a ring main, a 7.5kw shower takes 32.6amps, what you have I think is an RCCB, regards Terry

Answered 27th Oct 2012

tm property services

Member since 9 Mar 2011

hiya , you just divide the kw with the voltage so its 7500 divide 230 volts so it comes out at 32.6 amps , and the 30ma rcd is standard, do you mean a 40 amp circuit breaker .if so then it would be ok . hope this helps regards jason ( if unsure consult a local electrician , just to be safe ).

Answered 28th Oct 2012

jeh electrical

Member since 9 Oct 2012

Yeah that's perfect to run that shower off. Easy answer! Ha ha

Answered 28th Oct 2012

moffat twin electrical

Member since 2 Oct 2012

Need help with your project?

We have tradesmen ready to help you. Post a job, read reviews and hire today.

Post a job

Need some help?

Post a job on MyBuilder to find quality, local Electricians who can help you with your project.

Search all questions