Undertile Heating

[con1_uk]

Hello,

Further to my posts in the Tiling forum I have a few questions about under tile heating.

I have been looking at the mats/wires that go under the tiles and I want it fitted into my bathroom. My bathroom is only small (floor space 2sqm) I understand part P and I am going to get an electrician in to do the work.

From what I understand the system is the wires a probe and a thermostat.

Here are my questions

The booklet says RCD how will I know if I have this? I don't want to run a cable to the CU, can it be run of the socket or lighting circuit?

Does the thermostat go in the bathroom or outside?

Are these things safe under porous tiles even though they get sealed?

Thanks in advance.

 

[con1_uk]

Any help please?

 

[GaryMo]

Are you installing the cable or your electrician?
Your chosen electrician may not be impressed if he/she can't visually see the whole run of the cable, it's the only way he/she will be able to certify the installation.

There's a whole section in BS7671:2008 relating to floor heating systems so I would leave all your worries for your chosen electrician.

 

[davelx]

The loading of these is normally only a few hundred watts, so it may well be possible to supply it off the upstairs ring final with an FCU. In addition, if your upstairs ring final is not already RCD protected, then RCD FCUs are available.

You can tell if the upstairs circuit is already RCD protected by looking at your consumer unit - if you don't know what to look for you can post a picture here.

However, as you have said, you are aware of the requirements for Part P and will be getting an electrician to do the job. He will determine exactly what is needed when he comes to price the job.

As always, you are recommended to get three quotes if possible and to ensure that the electricians are members of a Part P Competent Persons Scheme.

 

[GaryMo]

The loading of these is normally only a few hundred watts, so it may well be possible to supply it off the upstairs ring final with an FCU. In addition, if your upstairs ring final is not already RCD protected, then RCD FCUs are available.

If he chooses to use twin & earth to spur the RCD FCU off the upstairs ring final and the cable is concealed at less than 50mm from the surface then the cable itself will also need RCD protection.
In this instance it would make more sense to use a standard FCU and install RCD protection at the consumer unit for the upstairs ring final, assuming it's not already RCD protected.

 

[Taylortwocities]

Well spotted. Gary.

The elctrician can also advise you re equipotentail bonding and if the lights in the bathroom will also require RCD protection...

 

[davelx]

If he chooses to use twin & earth to spur the RCD FCU off the upstairs ring final and the cable is concealed at less than 50mm from the surface then the cable itself will also need RCD protection.
In this instance it would make more sense to use a standard FCU and install RCD protection at the consumer unit for the upstairs ring final, assuming it's not already RCD protected.

Correct. I'm sure his electrician knows this and will advise accordingly .