Hi all,

I installed an electric underfloor heating cable in my new bathroom in the new extension i had built last year, i did the tiling over it on the floor and swithed it on on the 16th dec 2008 and it has worked fine ever since until recently when it tripped out the 30mA 80A RCD.

I have taken every thing out that is plugged into the rcd protected curcuit (Upstairs sockets) then turned on the rcd which stays on until the thermostat for the UFH switchs it on and then it trips!!

I am an experienced joiner by trade and did the laying of the cable and the tiling myself so nothing that i can imagine that has damaged the cable, could there be another reason i am over looking?

any help here would be great..Dave....

sparky415 wrote on Oct 27^th, 2009, 6:49pm:


Hi sparky
Yes taken front of stat every thing ok its a plasterboard box in ajoining bedroom built in wardrobe.
Checked all connections in stat back box even disconected floor sensor but got error msg on stat.
one point i havnt mentioned is that when i was laying out the cable i allowed for a 1000 x 800 shower tray but ended up putting a 1200 x 800 tray so theres 200 mm of over lap of the tray on the cables if you know what i mean. Slim line tray 35mm on  12mm travertine on flexi adhesive on no more ply on 22mm chipboard on 8 foot 8 x 2's
thx for your reply..dave

Don't blame him, lol  
The next step (if you don't have a tester) is to disconnect the element wires from the stat and run the thing,
If it does not trip we know there's a problem with the heater  

Thanks for that sparky, will do that tomorrow, ive got a stinkin cold and im off to bed.

Many thx for your interest cheers, will post result tomorrow thx again...dave

Dave!
Come back and tell us if it worked