RCD won't reset after all appliances disconnected-what now?

noexpertbutwilling · 4 Feb 2014

Woke up this morning in the dark to find that all our power was out. Trip to the cellar revealed RCD had tripped and wouldn't reset. 3 circuits protected by RCD and discovered that kitchen sockets were the culprit - RCD would reset with the other ground floor and upper floor rings on.

Unplugged everything from kitchen and conservatory, RCD still won't reset

Obviously I'm now into needing an electrician territory - any guesses as to likely causes? It has been fine since we moved in in October although it has of course been raining rather a lot!

Risteard · 4 Feb 2014

Cooker extractor hood unplugged? Fridge unplugged? Are these supplied from that circuit?

noexpertbutwilling · 4 Feb 2014

Risteard said:
Cooker extractor hood unplugged? Fridge unplugged? Are these supplied from that circuit?

Fridge Freezer unplugged (and re-powered from dining room for now) - yes it was on the circuit that tripped. Cooker extractor hood is a good call - I can't find where that is actually isolated from. It seems to be on the same circuit as it won't come on ... but as to where it is powered from ... hmmm. The cooker itself is fine - there's clearly a separate feed (and isolator) for that.

pompeygit · 4 Feb 2014

Probably a Earth to Neutral fault which will trip the RCD even with the circuit isloated. An insulation resistance test can confirm this. It could be something as simple as a neutral wire popping out of a socket and touching a metal back box. A sparky will be able to easily determine which 2 accessories the fault is between

Aragorn84 · 4 Feb 2014

pompeygit said:
Probably a Earth to Neutral fault which will trip the RCD even with the circuit isloated. An insulation resistance test can confirm this. It could be something as simple as a neutral wire popping out of a socket and touching a metal back box. A sparky will be able to easily determine which 2 accessories the fault is between

But hes managed to isolate it to the kichen, presumably by turning off the MCB's for each circuit in turn, which suggests to me that its a live-earth fault instead...

noexpertbutwilling · 4 Feb 2014

Aragorn84 said:
But he's managed to isolate it to the kichen, presumably by turning off the MCB's for each circuit in turn

Precisely - there are 3 MCB's downstream of the RCD. 1 for upstairs sockets, 1 for downstairs sockets and 1 for kitchen (& conservatory) sockets. The RCD will reset fine provided the kitchen one stays off.

pompeygit · 4 Feb 2014

Aragorn84 said:
pompeygit said:

Probably a Earth to Neutral fault which will trip the RCD even with the circuit isloated. An insulation resistance test can confirm this. It could be something as simple as a neutral wire popping out of a socket and touching a metal back box. A sparky will be able to easily determine which 2 accessories the fault is between

Click to expand...

But hes managed to isolate it to the kichen, presumably by turning off the MCB's for each circuit in turn, which suggests to me that its a live-earth fault instead...

Of course that's obvious, and thanks for pointing out...morning is not the best time of day!!!

noexpertbutwilling · 4 Feb 2014

Seems we have an almost dead short in a cable. Very odd as we've not been doing and screwing or drilling near there and the electrician also seemed surprised as everything was apparently in very good condition. Anyhow the test readings were pretty conclusive so we're converting the circuit into 2 radials to miss out the faulty segment for now.

Taylortwocities · 4 Feb 2014

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Taylortwocities
12 Apr 2012
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RCD won't reset after all appliances disconnected-what now?

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