power to electric underfloor heating

10 Mar 2024
Reaction score
United Kingdom
Following completion of a new kitchen extension I am converting part of the old kitchen into a new shower room. This is to include electric underfloor heating. The area of the shower room contains a, now redundant, cooker point fed from a dedicated circuit from the CCU and protected by a 40a MCB. It would be convenient to use this redundant cooker circuit to power the electric underfloor heating together with an electric towel rail. Is this feasible and what, if any, alterations might be required to the circuit. Presumably the MCB would need to be changed to one with a lower rating. Also the cable within the shower room might need to be extended via a junction box – would this need to be done with cable to match the existing 6mm2 cable? The area to be covered by the underfloor heating cables is 2.33m2.
Sponsored Links
It could theoretically be used, but a 40A circuit is grossly oversized for a few 100 watts of heating, and the cable is likely too large to physically fit into connection devices for UFH or a towel rail. Any junction box must either be accessible, or the cable joined using maintenance free connections.
All of it requires RCD protection, and it's also notifiable work.
The work is notifiable, it can cost more to get the completion certificate with the fees charged than to get an scheme member electrician to do the job for you.

I did it in part of a kitchen which was turned into a wet room, and I had a heck of a job convincing the LABC inspector I had the skill to do the work, in spite of being an electrician for 50+ years.

Cooker connection units can be used to allow connection to heavy cables, but the hurdle is to get the LABC inspector to agree, does not matter what we would do, it is not up to us. I had to fit a bathroom extractor in spite of having opening windows, the LABC inspector can insist as I found out.
Sponsored Links
Given you’ve just had an extension would it be worth asking the spark that did the electrics their opinion?

Also agree about the extractor too - think it would be a bit short sighted not to fit one

DIYnot Local

Staff member

If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

Select the supplier or trade you require, enter your location to begin your search.

Are you a trade or supplier? You can create your listing free at DIYnot Local