/ Advice on electrical fault?

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JJL - on 06 Jun 2013
Hi

Looking for some knowledgeable advice please?

Moved a fridge freezer (old one). On reconnect, it now trips the tripswitch. It does this even when the socket that I push the plug into is OFF.

Pushing the plug in slowly I find that the switch gets tripped as soon as the earth pin goes in (long pin).

I have opened the plug - nothing wrong in there.

So is the problem with the fridgefreezer or with the house electrics? And what should I do in either event?

Needless to say I'm an electrical numpty - but I thought that the earth was used to earth away from the appliance in the event that a live cable worked loose?

Thanks

J


Jim C - on 06 Jun 2013
In reply to JJL: not an electrician, but have you tried plugging in another appliance that is in normal use with no problems?

It just might be the earth on the socket ( my guess)
Also plug the fridge to another coke previously unused, and see if it trips.

A least I will rule in/ out some options.
Hooo - on 06 Jun 2013
In reply to JJL:
Are you absolutely sure it trips when only the earth is connected? If so, that has to be a house wiring problem. You should be able to connect anything to earth, it's supposed to be bonded to the ground. It sounds very unlikely though, try disconnecting brown and blue from the plug to make sure.
It's far more likely that some water from melting ice ran into somewhere it shouldn't be and is causing the fault. My favourite trick for dealing with this is to find a socket that isn't protected by the RCD ( the main switch that trips), and plug it in there so that it can run for a while and warm up. I have a socket specifically for my fridge that is not protected, so that if the house trips while I'm away, my food doesn't spoil.
Neil Williams - on 06 Jun 2013
In reply to JJL:

I would think the socket was faulty. Does it trip if you just push on it? Or if you get a plug with nothing wired to it at all (don't just cut the flex!) does it trip then? Is it the pressure on the socket, perhaps?

Neil
wintertree - on 06 Jun 2013
In reply to JJL:

If you touch the unplugged fridge do you get an electric shock? Is it in contact with a kettle or toaster etc? Is it sitting on, or otherwise in contact woth, a cable for something else? These might all explain the problem you describe.

Alternatves include a dangerously damaged socket or, discounting your earth only commejt, a neutral/ground short in the fridge and an imballence on your neutral line in the house.

Or perhaps here is some other machinery, e.g. a fan or ionic precipitator,, on the fridge perhaps if is building up a static charge that discharges via earth.

Is your trip switch earth leakage or an RCD?

If really obvious things are ruled out then it's sparky time, erratic mains power problems are a warning...
Philip on 06 Jun 2013
If the socket works fine with another high load device (try a kettle), then the fault is a Neutral to Earth fault on the fridge.

Even switched off a neutral to earth fault will cause the RCD to trip when there is sufficient load on the whole house.
Jim C - on 06 Jun 2013
In reply to Hooo:
> (In reply to JJL)
My favourite trick for dealing with this is to find a socket that isn't protected by the RCD ( the main switch that trips), and plug it in there so that it can run for a while and warm up. I have a socket specifically for my fridge that is not protected, so that if the house trips while I'm away, my food doesn't spoil.

How would I identify one of those unprotected sockets, that would be handy for fridges etc.?

All my circuits are on a single Consumer Unit with an RCD, and I assumed then that all sockets/ on circuits or spurs would be protected. Is that not the case?
Neil Williams - on 06 Jun 2013
In reply to Jim C:

Normally you can identify an unprotected circuit by it being positioned separately in the consumer unit. That said, I'm not sure on what basis you can have an unprotected circuit these days. I did think the driver for it was that all socket circuits should be protected, as they could have gardening equipment etc plugged in.

Didn't think about a neutral to earth fault - that's a good point and wouldn't be visible in normal operation without an RCD (i.e. for all I know my fridge might also have that, because I have an old style fuse board with no RCD at all).

Neil
Neil Williams - on 06 Jun 2013
In reply to Jim C:

The solution to this once they get cheap enough is an RCBO (combined breaker and RCD) for every circuit, so you don't ever "trip the whole house".

Neil
wilkie14c - on 06 Jun 2013
In reply to JJL:
when you say you have moved the fridge do you mean you have moved it to a nerw location and therefore you are now using a different plug socket to the old location? If so then you need to plug in the fridge back to its orginal socket, use extention lead if you can't easily move the fridae back. This will tell you if it is the frisge or the socket with the problem.
Nutkey on 06 Jun 2013
In reply to Jim C:
> (In reply to Hooo)
> [...]
> My favourite trick for dealing with this is to find a socket that isn't protected by the RCD ( the main switch that trips), and plug it in there so that it can run for a while and warm up. I have a socket specifically for my fridge that is not protected, so that if the house trips while I'm away, my food doesn't spoil.
>
> How would I identify one of those unprotected sockets, that would be handy for fridges etc.?

Trip the RCD, and then see what still works.

Upstairs sockets are usually unprotected (unless your house has had a recent rewire).

> All my circuits are on a single Consumer Unit with an RCD, and I assumed then that all sockets/ on circuits or spurs would be protected. Is that not the case?

If the RCD is the same side of the consumer unit as the main switch, then probably all circuits are protected.

If the RCD is the opposite side, it's probably a split load installation, which means there might be an unprotected socket.
JJL - on 06 Jun 2013
In reply to JJL:

Hi everyone

Thanks for your comments.

A few clarifications:

- "moved" is 200 miles, not from one end of kitchen to other.
- a sawn off plug doesn't trip
- the fridgefreezer trips no matter which socket it goes in (tried 3)
- other things (including a kettle) work fine in the socket.
- no shock touching unplugged (or plugged but tripped) fridge

Sounds like a neutral to earth fault in the fridge... probably from defrost then move. I'll let it dry a few days then try again.

thanks again

Jim C - on 06 Jun 2013
In reply to Nutkey:
> (In reply to Jim C)
> [...]
>
> Trip the RCD, and then see what still works.
>
> Upstairs sockets are usually unprotected (unless your house has had a recent rewire).
>
> [...]
>
> If the RCD is the same side of the consumer unit as the main switch, then probably all circuits are protected.
>
> If the RCD is the opposite side, it's probably a split load installation, which means there might be an unprotected socket.

Cheers for that, all sockets protected .
The only thing not protected is the smoke alarms, which have their own switch, an do not go off when the RCD trips.

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Hooo - on 06 Jun 2013
In reply to JJL:
> (In reply to JJL)
>
> Hi everyone
>
> Thanks for your comments.
>
> A few clarifications:
>
> - "moved" is 200 miles, not from one end of kitchen to other.
Ah, how about this for an explanation then...
You didn't have an RCD in the old place (or it was less sensitive, or not working). The fridge has been faulty for years, and you've only just found out.
Still worth warming it up and trying again though. Leave it outside if the weather stays nice.

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