Towel rail fault

[socket2me]

Had a customer call me today with an RCD fault on a towel tail. When they turn the towel rail "on" its fine and heats up. When they turn the towel rail "off" it trips the RCD.....

I had it last year on a different property and replaced towel rail which fixed the problem but id like to know why it trips when turning off.... Any ideas please? The towel rail has obviously been working fine for several months now but has just started developing this fault.

Cheers

 

[Midwest]

Beats me, something to do with latent heat reducing resistance in fault. Did you IR test element?

 

[Richard Burns]

I would expect it is something to do with existing leakage current on the installation and the arc flash on switching off is just inducing or arcing voltage to earth and changing the switch may help.

 

[socket2me]

I will carry out IR test on it tomorrow and see. I would have thought it would arc more switching load on.... Strange one.

 

[Midwest]

And as Richard said, do earth leakage test on installation.

 

[PEG]

I will carry out IR test on it tomorrow and see. I would have thought it would arc more switching load on.... Strange one.

Not always so...opening contacts under load allows an arc to "draw out",which can increase the size/duration of said arc,and instigate an issue not experienced when closing same contacts.

...And who needs a towel rail? ...don't you lot pop a rock in the oven,at tea time,and wrap your towels round it,whilst the custard is warming?

 

[Deleted member 26818]

Check whether the switch is single or double pole.
If it is double, try installing a single pole switch temporarily to see if it makes any difference.