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mush

Rcd Woes...

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just fitted a new WYLEX 17th edition dual RCD consumer unit in my house.

However, im now having problems with one of the RCDs. it keeps tripping! :realmad:

The RCD concerned is an 80amp 30mA which feeds the shower and the cooker. Ive got the 63amp 30mA RCD feeding the socket and light circuits. This sound ok?

....When you use the test button on the 63mA RCD, both the RCDs trip. However if you test the button on the 80mA RCD, only that RCD trips.

....When all the circuits are turned on together, eventually (1-15min) the 80mA RCD trips.

....If all the circuits are on and you turn on an appliance on the socket circuits (either one) the 80mA RCD trips which doesnt even feed them. The RCD thats feeding them stays on sometimes, but other times trips also (possibly because the other RCD has caused it to trip?).

....The 63mA RCD feeding the sockets etc is happy and has no probs aslong as the 80mA RCD is off.

....Ive 500v meggered all the circuits and they are all healthy (>1000) with correct continuity.

....Earth loop impedance is good at 11 ohms (TT)

....With everything disconnected, and incoming power only, both RCDs sit healthy and dont trip.

Any ideas ive possibly missed or advice? Possible faulty RCD? Should i swap the RCDs to see if the problem persists or changes in nature? Could it be a faulty appliance? - but if so why does it trip the RCD thats not even feeding it?...possible earth/neutral fault on an appliance?

All comments appreciated.

Edited by mush

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polarity is good on all the circuits. considering the age of the old board i pulled out, the wiring is in very good nick...

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polarity is good on all the circuits. considering the age of the old board i pulled out, the wiring is in very good nick...

you havent mixed up the socket circuit neutral legs have you? ie ring 1 neutral + neutral 2 and vice versa?


"If you carry your childhood with you, you never become old. Why rush to end life when happiness is in the blissfulness of childhood innocence."

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Guest old-hand
you havent mixed up the socket circuit neutral legs have you? ie ring 1 neutral + neutral 2 and vice versa?

Hence "crossed paths"

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Similar problems happen when the CU's fly leads that connect RCD's to their neutral bars are wrong way round. Reason nothing trips when nothing is turned on is.... RCD's monitor for differing currents on Line and Neutral. No current flowing = No difference in currents.


Trade Member

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just fitted a new WYLEX 17th edition dual RCD consumer unit in my house.

However, im now having problems with one of the RCDs. it keeps tripping! :realmad:

The RCD concerned is an 80amp 30mA which feeds the shower and the cooker. Ive got the 63amp 30mA RCD feeding the socket and light circuits. This sound ok?

....When you use the test button on the 63mA RCD, both the RCDs trip. However if you test the button on the 80mA RCD, only that RCD trips.

....When all the circuits are turned on together, eventually (1-15min) the 80mA RCD trips.

....If all the circuits are on and you turn on an appliance on the socket circuits (either one) the 80mA RCD trips which doesnt even feed them. The RCD thats feeding them stays on sometimes, but other times trips also (possibly because the other RCD has caused it to trip?).

....The 63mA RCD feeding the sockets etc is happy and has no probs aslong as the 80mA RCD is off.

....Ive 500v meggered all the circuits and they are all healthy (>1000) with correct continuity.

....Earth loop impedance is good at 11 ohms (TT)

....With everything disconnected, and incoming power only, both RCDs sit healthy and dont trip.

Any ideas ive possibly missed or advice? Possible faulty RCD? Should i swap the RCDs to see if the problem persists or changes in nature? Could it be a faulty appliance? - but if so why does it trip the RCD thats not even feeding it?...possible earth/neutral fault on an appliance?

All comments appreciated.

As others have said, 99% likely to be a neutral fault somewhere.

One thought - you haven't got a gas hob with a plug top ignition? And common bonded the hob and electric oven?

Bill.


Bill

Accord Fire & Security Services Ltd.

www.accordfire.co.uk ~ TEL: 0845 474 5839

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Try posting in the UK electrical section of www.diynot.com, you will get some good info (the respondents can get a bit sharp though, Part P and competance are their usual chants lol)

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I aint a sparks, so dont laugh !

Have you tried whacking it with a screwdriver handle.........could it just be a dodgy RCD ?

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Try posting in the UK electrical section of www.diynot.com, you will get some good info (the respondents can get a bit sharp though, Part P and competance are their usual chants lol)

you probley got the netural cables from the rcds on the wrong neutral bars some of the wylex boars have 3 netural bars have you tested the trip times with your rcd tester test them on half trip they shouldnt trip out if they do then they faulty i install wylex boards all the time and never had a problem with the rcds

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cheers for the responses guys.

turns out i thought the wiring in was in good nick,...but wasnt lol

neutral from the electric cooker and ground floor ring main circuits were bonded together in a junction box under the floor boards. looked like someone had cut them in the past and then joined it all together. problem sorted as soon as i ripped it to bits then wired it properly!!

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Guest old-hand

Glad we could help.

fanx for letting us know the result.

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As Oxo-we're all still on a learning curve!.

Well apart from me I know it all!-But on behalf of my forum companions thank you-lol. :whistle:

cheers Richard.

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