Bathroom under floor heating from Shaver Point

[PEH1962]

Hi,

I am having some under floor heat mats installed (4 x 150W), and the only convenient wiring is to a shaver point (which is a spur from the lighting ring).

The shaver point is going, but the spur will power an LED mirror, but I wondered if I could further run the heating mats from the same spur?

Any advice would be really appreciated.

Many thanks,

Peter

 

[Iggifer]

600w of heating is going to do absolutely nothing to warm the floor, never mind the room.

That aside, it's only 2.6A so technically you could, it would only leave you with 3.4A for the rest of your lighting circuit with the heating on though.

I would go for a spur from a ring main before coming off a lighting circuit, that just reeks of poor design.

Is there not an airing cupboard you can get a cable route into?

 

[OwainDIYer]

Very bad practice.

Apart from anything else, most lighting circuits won't have much spare capacity (assumed 100W per point or actual load if greater) and may not be RCD protected.

 

[ericmark]

Often lighting is not RCD protected any new wiring in a bathroom should be RCD protected specially any underfloor heating.

I installed underfloor heating in my mothers wet room. It was a total failure.
1) It took around 1 hour to heat up so unless left on 24/7 mother had finished her shower before it warmed up.
2) Any hotter and you could not walk on the floor yet the room remained cold lucky also a towel rail which warmed the room better.
3) Once she had a shower the shower water cooled the floor and it took a good 1/2 hour to re-heat. Whole idea was to dry floor after a shower so failure.
4) The controller failed 3 times in first 5 years.
5) The sensor in the floor failed and got stuck in the pocket so could not be renewed without lifting tiles.
6) It was rarely used for first 5 years and today is never switched on so a lot of work for nothing.

The maths is easy extractor removes a set amount of air which is replaced with air from the house which we hope is already warm. In mothers case air was from a cold draughty hall. The towel rail or underfloor heating warms that air a little more but 15 l/m or air takes some warming and the underfloor heating can't warm the air quick enough.

Under floor heating has been with us for many years

there is a good reason why we did not continue with the Roman invention it simply does not work.