RCD tripping on Electric towel rail

[vaderag]

My RCD keeps tripping on my electric towel
I did have a smart switch (Shelly1) wired in so assumed it was that, but I have now removed that and still tripping

This means it's either the socket (a fused flex socket) or the heating element itself

Note, it's tripping the RCD and not the MCB

How can I work out which it is, and why would it be tripping just the RCD - research suggests water ingress which I guess would be possible for either tho more likely in the towel rail...

 

[yorkspark]

neutral earth fault on the towel rail element

Common fault and needs replacing

 

[vaderag]

neutral earth fault on the towel rail element

Common fault and needs replacing

Wow, that was quick!
I worried someone might say that, the rail weighs a ton! It's also not that old annoyingly!!

Just one question, it seemed to work one time and then didn't - could that fault be intermittent??

And definitely not some water somehow ingressed into the socket?

 

[yorkspark]

the insulation on the element breaks down, causing a neutral earth fault, which in turn will cause an rcd/rcbo to trip

water cannot traverse the flex from appliance to socket/fcu, if the fault was in the socket/fcu, then you wouldn't be able to reset the circuit.

 

[vaderag]

Great, thank you! Been tearing my hair out over this as I was sure it wasn't my wiring but was beginning to doubt myself until I removed everything!

Guess I'll get on to the manufacturer for a replacement