underfloor heating

[spurs1980]

Evening guys
Got a job tomorrow to sort an electric underfloor heating apparently the under floor heating starts to get warm then trips the rcd
The builder disconnected the thermostat an tried again the floor got warm then tripped the rcd again
Any pointers would be apreciated
Thanks

 

[ajelec10]

Fist disconnect element, continuity test l-n should get resistance depending on size of Matt and wattage say 4m square floor 200w per m = 800w so should be around 65 ohm. Then IR test element L + N strapped together to earth. Should be greater than 2 mega ohm sounds like faulty element and the tiles are being ripped up!

 

[Octopus]

Interesting "the builder" - has it just been installed, and if so by whom and what tests did they do?

 

[spurs1980]

Ok chaps
Checked mate says on lead should be 96 ohms I got 97 insulation resistance came out at 17 mega ohms
Just wired back in to see it it will trip while I'm here
Any clues
Thanks

 

[telectrix]

IR test the circuit back to the CU. it could be a fault that is only tripping the RCD when a laod is applied.