Possible Earth fault on oven.

[neon_3SP_glow]

I am using a metal sink as an Earth point to do a continuity check on an oven’s Earth connection. Basically checking that the internal wall wiring is all in check.

Running from the washing machine drum to the sink gives a perfect reading of no resistance. As expected.

Running from the cooker hood to the sink also gives a perfect reading of no resistance.

Running from the either the oven or hob (both cables are joined together in a wall socket) gives an open circuit reading.

I have removed the wall socket that both appliances are wired into and verified the Earth wire connections all around. Everything is connected properly.

There is also a gas pipe in the area and there is no continuity between that and the wall socket. It’s as if the wall socket Earth wire is not connected to an Earth.

Now the strange thing is this…

The wall socket has an isolation switch above the worktop, this also has a plug socket.

I have a plug socket tester and it is reading correctly… Almost. A correct reading is the two green LED’s fully lit and the Red LED unlit. It appears the middle LED (which would be unlit to signal an Earth fault) is slightly dimmer than it should be. It is on, but not quite as bright. I have verified this ‘brightness’ issue by testing other sockets in the customers home.

Any ideas please? Sorry for the wall of text and thank you if you managed to stick by and read through it.

Ps. I have advised the customer to not use either the hob or the oven until I can be sure it is safe.

Obviously my first port of call would be to call an electrician. But, the job is for an estate agent, and they would not appreciate me needlessly calling an electrician out on their behalf.

I’m sure I am not wrong and there is a problem though.

[Martin]

Re: Possible Earth fault on oven.

Does the oven and hob then have their own supply back to the MCB?

[neon_3SP_glow]

Re: Possible Earth fault on oven.

I would presume so. I worked on the machine with the isolation switch off. Of course I test for any voltage.

Would it having its own circuit affect the Earth test? I can’t see how it could.

[timdowning]

Re: Possible Earth fault on oven.

Have you actually checked continuity of the cpc wire itself (disconnected it from the plate – socket) from the oven/hob to the wall socket.

The cpc wire that runs from the cooker switch plate all the way back to the Consumer unit (should be connected with the bank of cpc’s in a block)

If this is the case which it should be then it doesn’t matter if its on its on MCB.

[Author]

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