mush Posted May 12, 2009 Posted May 12, 2009 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! 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.
mush Posted May 12, 2009 Author Posted May 12, 2009 polarity is good on all the circuits. considering the age of the old board i pulled out, the wiring is in very good nick...
satsuma01 Posted May 12, 2009 Posted May 12, 2009 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.""We all die, the goal isn't to live forever, the goal is to create something that will." 07475071344
Guest old-hand Posted May 12, 2009 Posted May 12, 2009 you havent mixed up the socket circuit neutral legs have you? ie ring 1 neutral + neutral 2 and vice versa? Hence "crossed paths"
dpaengineer Posted May 12, 2009 Posted May 12, 2009 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
DirectFS Posted May 12, 2009 Posted May 12, 2009 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! 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
spider Posted May 13, 2009 Posted May 13, 2009 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)
SUBS Posted May 13, 2009 Posted May 13, 2009 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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