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Crabtree RCD trips (Read 10451 times)
Matt
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Crabtree RCD trips
Jun 20th, 2004, 3:19pm
 
Hi there, I have a Crabtree Starbreaker Consumer unit in a house I have recently moved into. The house is about 9 years old. Every so often (twice in the last 3 weeks) the RCD trips. There is nothing special happening. This latest time I was just watching TV, before I was in the garden.
After the RCD trips it will not reset unless I turn off all the MCBs and then turn on the RCD and then all the MBDs. Everything then comes back on and all seems well again. If/when it happens again I will try going through turning one MCB off at a time trying the RCD to see if that helps point towards the problem.
Has anyone got any other ideas that might help me please?

It is a split load RCD protecting the sockets around the house, the kitchen sockets, the immersion heater (which is not on) and the cooker (which wasnt on at either time). It says on the RCD "RCCB 63A 30mA" I dont understand the difference in the two current readings on it but understand that the 30mA is the trip current, should I get a higher rated RCD? (Although only a 3 bed semi, I do put a reasonable drain on the electricity). We have just installed a new Fridge and a new Freezer however the first time it happened was with our old Fridge/freezer and the second time was with the new appliances.

Many thanks in advance for any help.
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plugwash
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Re: Crabtree RCD trips
Reply #1 - Jun 20th, 2004, 3:33pm
 
some appliances give a slight earth leakage and this can be higher when first turned on

some people find computers to be a problem although we have never suffered from this issue ourselves

id get the wiring tested by a sparkie it may well be it is starting to fail and contributing to the problem
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LSpark
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Re: Crabtree RCD trips
Reply #2 - Jun 20th, 2004, 10:43pm
 
[quote author=Matt  link=1087741145/0#0 date=1087741145]Hi there, I have a Crabtree Starbreaker Consumer unit in a house I have recently moved into. The house is about 9 years old. Every so often (twice in the last 3 weeks) the RCD trips. There is nothing special happening. This latest time I was just watching TV, before I was in the garden.
After the RCD trips it will not reset unless I turn off all the MCBs and then turn on the RCD and then all the MBDs. Everything then comes back on and all seems well again. If/when it happens again I will try going through turning one MCB off at a time trying the RCD to see if that helps point towards the problem.
Has anyone got any other ideas that might help me please?

It is a split load RCD protecting the sockets around the house, the kitchen sockets, the immersion heater (which is not on) and the cooker (which wasnt on at either time). It says on the RCD "RCCB 63A 30mA" I dont understand the difference in the two current readings on it but understand that the 30mA is the trip current, should I get a higher rated RCD? (Although only a 3 bed semi, I do put a reasonable drain on the electricity). We have just installed a new Fridge and a new Freezer however the first time it happened was with our old Fridge/freezer and the second time was with the new appliances.

Many thanks in advance for any help. [/quote]

what you have there is a split load consumer unit, one side is protected by an RCD\RCCB unit, and one side is unprotected.

Your Residual Current Circuit Breaker (RCCB) is rated at 63A this is the maximum loading you should put on the RCCB, the 30mA is the rating it will trip on earth leakage, this is the normal range of RCCB to give protection to yourself and others, this cannot be any higher as this will not give adequate protection to yourself.

I would suggest firstly you switch all MCB's off and switch the RCCB on, switch each MCB on and then off, this will find any circuit with blatent fault on it, failing this also try with MCCB on and switch the MCB's on one by one until all on, if still no problem you most likely have a problem with some plug in equipment you or someone else is using

This is most i can suggest to you right now
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supersparky
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Re: Crabtree RCD trips
Reply #3 - Jun 20th, 2004, 10:52pm
 
if its intermittent its most likly a rcb thats over sensitive combined with slight earth leakage fron an appliance/ intermittent high earth leakage from an appliance/ a over sensitive and tempermental rcd.

the way to locate the fault, if you dont have a clue where it may be is to put each circuit in turn on the non rcd side of the CU until it stops trpipping.
or a multimeter maybe able to find continuety between live and earth- it must be capable of low readings, this is how i ususaly go about finding them, it only works if the appliance is always giving out slight leakage and just peaks sometimes and trips.
id advise you get somone to look at the problem. where are you located, we maybe able to give you some idea of price

ss
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Re: Crabtree RCD trips
Reply #4 - Jun 20th, 2004, 10:58pm
 
Thanks for all your replys. It is intermittent, at the moment everything is working fine, but at some point I expect it to trip again.
I am in Torquay in Devon, what would I need to ask for an Electrician to look at if I were to call one in, and what sort of costs would I expect to have to pay for the required tests/work?

Many thanks
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Re: Crabtree RCD trips
Reply #5 - Jun 20th, 2004, 11:02pm
 
i know we had asparky from devon a while back...
not sure now, ill ask and get back

ss
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Beanzy
Re: Crabtree RCD trips
Reply #6 - Jun 20th, 2004, 11:18pm
 
Try unplugging the fridge and freezer next time. I had hell with one a while back and It was the faulty fridge kicking in.

I'm down Bodmin way,  just a bit too far to make economic sense to go up I'm afraid. You should be able to get someone local from the yellow pages etc. Problem is RCD faults can take hours If they're not the usual suspect items. Maybe get someone in for a couple of hrs and then if no joy get them to come back after a few days to give time to ponder if it's a difficult one.
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« Last Edit: Jun 20th, 2004, 11:23pm by Beanzy »  
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Re: Crabtree RCD trips
Reply #7 - Jun 24th, 2004, 10:52pm
 
Does anyone know if a computer UPS could cause this type of issue, especially if the battery is low?
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Re: Crabtree RCD trips
Reply #8 - Jun 24th, 2004, 11:34pm
 
that sounds unlikely, however the computers themselfs create earth leakage, which is normal but can build up and then may trip RCD unit..
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Re: Crabtree RCD trips
Reply #9 - Jun 25th, 2004, 12:13am
 
the ups is almost certainly switched mode so i wouldn't rule it out

best practice is to have computer equipment on non rcd anyway as it is farly normal to get earth leakage from it

also the earth leakage from switched mode psus is pretty much impossible to detect with normal tools because it is at much higher than mains frequency (this may also be why some rcds trip more easilly on it than others)

if your computer is upstairs i would move your upstairs ring to the non-rcd side (remember to move the neutral to the correct bar as well)
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