Underfloor Heating tripping RCD

[Octopus]

A mate of mine has just had his floor tiles replaced and now when he turns on the underfloor heating the RCD immediately trips. Seems like the chap who laid the new tiles has damaged the element.

Apart from ripping up the floor is there anyway to determine where the break is? I recall hearing a while ago that there is a way to do this!

Any suggestions welcome.

Thanks

 

[Deleted member 9648]

Bit pointless finding the location of the damage as the wires cannot be repaired,the whole lot will have to be replaced.
IR test the element,disconnected from the supply....if it's down the only option is floor up and replace......

 

[telectrix]

problem is, you may not have a break. the RCD trips on earth leakage. first, you must IR the element to make sure it's that that is at fault. if it is, i think the floor will have to come up as you will have to replace the element.

 

[davelerave]

test it anyhow at 250v-simple job

dunno anything about electric underfloor-is it usual to rcd these then?

 

[Deleted member 9648]

test it anyhow at 250v-simple job

dunno anything about electric underfloor-is it usual to rcd these then?

'Tis a requirement of bs 7671.

 

[Guest123]

You could pinpoint the short using continuity testers and a bit of ohms law, providing you know exactly how it's laid. But as the chaps have said if it is damaged then the whole lot needs replacing!

Unlucky tiler!!!!

 

[telectrix]

damn it wirepuller, you beat me to the post

 

[work4aliving]

Bit pointless finding the location of the damage as the wires cannot be repaired,the whole lot will have to be replaced.
IR test the element,disconnected from the supply....if it's down the only option is floor up and replace......

The cable can be repaired, you just wont have heating on the small repaired part. IR test with a thermal imaging camera can determine where the break is. Specialist engineers however, cost an absolute fortune. You'll find that 99% of electric UFH is earth braided/shielded meaning its easy to nick the insulation when floating adhesive and get tripping issues.

 

[Knobhead]

Use differential ohm calculation to try the work out the point of the fault. If you can tie the fault to around a metre square it saves the entire floor being ripped up.

But to be honest the most likely point for a fault is where the cable goes under the floor.

 

[Deleted member 9648]

The cable can be repaired, you just wont have heating on the small repaired part. IR test with a thermal imaging camera can determine where the break is. Specialist engineers however, cost an absolute fortune. You'll find that 99% of electric UFH is earth braided/shielded meaning its easy to nick the insulation when floating adhesive and get tripping issues.

How is it repaired?