Undertile heating in a shower room - wiring regs

[shannyla]

Just seeking some clarification on the wiring regs regarding electric undertile heating in an ensuite shower room.

The heating cable will be laid in zone 2, will be on an RCD protected circuit and with the thermostat and fcu located outside the room. The cable will be of the appropriate IP rating.

My one query is that I'm considering running UTH as a fused spur off the ring main as it's difficult to run a new circuit to the location. Is this a no-no, as I suspect it might be?

Is there anything I've missed? I know this is notifiable work and will follow due process with the LABC...

 

[sparkybird]

depends on the power requirement for the heating - what is it (in kW or Amps)?

 

[shannyla]

The rooms are small so the draw will be very low for UFH - 400w in one room and 700w in the other. It's supplementry heat to take the chill off the tiles.

 

[mikeyd]

Not a problem feeding them off fused spurs. Put a 3A fuse in the 400W, and a 5A fuse in the 700W.

 

[shannyla]

Thanks Mike, good one.

 

[Taylortwocities]

I trust you have a copy of the Wiring Regulations? The new regs (BS7671 - 2008) include more detailed and stringent rules for underfloor heating.
These include the types of floor allowed(in shower rooms etc) and a the very detailed plan and other information that must be provided as part of the installation.

The new regs has a whole section (753) dedicated the Floor and Ceiling Heating Systems. You'll need to be conversant with these as well as the requiremetns for RCDs etc as part of the general wiring requirements.

 

[ban-all-sheds]

Shannyla - when you applied for Building Regulations approval, what did you put on it about the way that you would ensure that the electrical work would comply with Part P?

That's not a trick question - it's not unusual for people copy down what the council tells them to write on the application, and don't give any thought to what they are actually committing to, and then find themselves in all sorts of bother when they don't abide by it, usually right at the end when they find that they can't get their completion certificate from the council.

 

[electronicsuk]

Definitely don't buy an undertile heating kit that uses unscreened cable...

 

[Taylortwocities]

Definitely don't buy an undertile heating kit that uses unscreened cable...

It is a requirement that earth screened cable must be used for UFH in bathrooms. 701.753 refers.