RCD tripping on Electric Under-floor Heating

[Mefster]

Had my sons’ bathroom completely redone about 8 years ago, including the having electric underfloor heating. The room is over a car port so can get pretty cold in Winter.

It worked without an issue for some time, but recently I noticed the RCD keeps tripping (30mA).If I reset it the control panel switches on but trips again after a few minutes.

I guess the issue could be the RCD, control panel or an issue with part of the wiring/matting. Is there any way to investigate to try to narrow it down? Is it worth replacing the RCD?

I’m hoping it won’t require the floor ripping up!

 

[ericmark]

There are three tools, the insulation tester, the clamp on ammeter, and the RCD tester all which can be used to find the fault, but the cost of the tools means little one can do DIY wise to find the problem. It is more likely the mat to being the RCD.

 

[blup]

It’s worth checking it, and also doing an insulation resistance test as well as a physical inspection. It requires a lot of expensive kit so worth getting a professional sparkie in

Blup

 

[JohnW2]

I guess the issue could be the RCD, control panel or an issue with part of the wiring/matting.

Yes, that covers most of the possibilities.

Is there any way to investigate to try to narrow it down?

Yes, but as has been said, because of the test kit required, you really need to employ an electrician.

I’m hoping it won’t require the floor ripping up!

I'm sure you are but, without wanting to be too pessimistic, I suspect/fear that that's the most likely of the three main possibilities you've mentioned. That's one reason why I wouldn't personally dream of having electric UFH!

Kind Regards, John

 

[Mefster]

Thanks for all the replies and advice. Electrician contacted. Might be the New Year so I may just swap out the RCD to see if that makes a difference. If not I’ll leave it to the professional

 

[JohnW2]

Thanks for all the replies and advice. Electrician contacted. Might be the New Year so I may just swap out the RCD to see if that makes a difference. If not I’ll leave it to the professional

Thanks. It's not impossible, but probably not all that likely, that the RCD is the problem.

Let us know what the outcome is!

Kind Regards, John

 

[Taylortwocities]

I may just swap out the RCD to see if that makes a difference.

It won’t. The RCD is doing its job, there’s a fault, somewhere.

 

[Diver Fred]

You or your son should have been left with the installation manual which contains the installation test results. With those the electrician can make a comparison of the test figures. Without - it's best guess.

 

[JohnW2]

You or your son should have been left with the installation manual which contains the installation test results. With those the electrician can make a comparison of the test figures. Without - it's best guess.

Not a difficult 'guess' though. It would be at least 'surprising' if the initial insulations resistance measurement had not been "immeasurably high".

In any event, it doesn't really matter what the insulation resistance was initially (even if it was 'measurable') - what matters is the IR of various parts of the circuit in question (mat, wiring etc.) now.

Kind Regards, John