What made my trip trip?

[Melking]

I was minding my own business at home yesterday when there was a clunk from the hall which I didn't even realise was the trip going as nothing was running apart from the laptop which kept going on the battery. Anyway, when I realised what it was I tried to reset it but it wouldn't stick. I found it was the circuit that covers the living room and upstairs sockets but even when I unplugged everything - even the smoke detectors - it still wouldn't reset. There are two wires in that circuit, presumably upstairs and downstairs, and I tried removing them one at a time to limit my search but that made no difference. Then, after maybe an hour, I was able to reset the trip, though I have no idea whether I did anything to alter the situation, and I plugged everything back in bar the shed which I'd unwired in desperation and the smoke detectors and it's been working fine. Can't help but worry it's going to trip again though and wondered if anyone could suggest what the problem might have been, or why it seems to have fixed itself, or if there's anything I should do to prevent it happening again. It was a lovely dry day and the house doesn't leak though it's cold and there's rather a lot of condensation, so could it be damp? It was no worse than on very many previous occasions though. The 'fuse box', though it's nearly 30 years old, has no fuses, just switches for the various circuits and the trip. Never had this problem before. Any ideas???
Thanks.

 

[ericmark]

What tripped

could be mouse or spider.

 

[chivers67]

If it's something like the above it's tripped due to either an Earth to Neutral leakage of some kind or an imbalance in the circuit sometimes even caused by a lose connection. Any damp areas in your home?

 

[oldbutnotdead]

Shed. If the Thing that tripped had a test button on it then most likely there's an N-E fault caused by damp in the shed. Removing L only from the Thing won't fix it. An hour's sunshine on the other hand will dry the damp out nicely......

 

[Melking]

Shed. If the Thing that tripped had a test button on it then most likely there's an N-E fault caused by damp in the shed. Removing L only from the Thing won't fix it. An hour's sunshine on the other hand will dry the damp out nicely......

Thanks. Yes, damp in the shed seemed likely but I disconnected the wires from the back of the socket in the shed and the trip still tripped though they couldn't possibly have been shorting as they were 'floating' in mid air some distance apart. Unless it was something between the house socket the feed was taken from and the shed, but that shouldn't be exposed to the elements at all. Actually, the shed wasn't as damp as I've seen it in the past and I certainly didn't notice any dampness at the socket.

 

[Melking]

If it's something like the above it's tripped due to either an Earth to Neutral leakage of some kind or an imbalance in the circuit sometimes even caused by a lose connection. Any damp areas in your home?

Thanks. No, not what you'd really call "damp", though it can get pretty humid with a lot of condensation on the windows, but it wasn't especially bad yesterday. I had problems long ago when the shed roof leaked and wetted a connection but that's not the cause this time.

 

[oldbutnotdead]

You still haven't revealed whether the Thing is an RCD or an MCB...it does make a difference! Any outside lights, any junction boxes on the shed feed, what sort of cable (SWA, t & e, flex) is going to the shed.....

 

[Melking]

You still haven't revealed whether the Thing is an RCD or an MCB...it does make a difference! Any outside lights, any junction boxes on the shed feed, what sort of cable (SWA, t & e, flex) is going to the shed.....

Ah, that's because I have no idea what all these things are! I do know there are no junction boxes on the way to the shed. There is an outside light, though I haven't used it for years, and I don't know any reason it would play up yesterday but not in today's fog or on any of pouring wet days over those years. The "Thing that tripped", as you call it, does indeed have a test button.

 

[JohnW2]

Ah, that's because I have no idea what all these things are!

Eric showed you pictures of the various possibilities in post #2 (all of this things he depicts, apart from the 'isolator', can 'trip'. The most useful thing to tell us is whether or not the thing that tripped has a 'test button' (which means RCD or RCBO - MCBs don't have a test button).

Kind Regards, John

 

[JohnW2]

It is not a fuse box then is it?

Maybe that's why he/she put the phrase within quote marks?

 

[Melking]

Eric showed you pictures of the various possibilities in post #2 (all of this things he depicts, apart from the 'isolator', can 'trip'. The most useful thing to tell us is whether or not the thing that tripped has a 'test button' (which means RCD or RCBO - MCBs don't have a test button).

Kind Regards, John

I did tell you! Yes it does. And it doesn't look like any of those pics. There is one trip, one reset button and a line of switches for the various circuits. It's what most people, me included, would call the 'fuse box', though there are no fuses, which is indeed why I put the phrase in inverted commas, Thank you JohnW2!

 

[RandomGrinch]

Could you post a picture of the offending 'fuse box' and let us know which trip, tripped!?
It may help us understand

 

[ericmark]

Typical consumer unit with the parts identified. There is I am sure a test button with the RCBO's but not easy to see it. Had to photoshop it together and could not find a picture of a RCBO direct on. It seems likely the items tripping is the RCD, which as well as test button will have other markings for example. Or 30 mA or 0.030 A there will be something.

Seems likely it is a RCD tripping and where there are 4 or 5 MCB's and one RCD it can be a problem working out what has tripped it.

The RCD measures the difference between line amps and neutral amps, and assumes if not the same some current must be going to earth, a line to earth fault is normally easy to find, it is the neutral to earth fault which causes problems.

Neutral is nearly at same voltage to earth, so how much current flows neutral to earth is not only dependent on the resistance to earth but also the voltage between neutral and earth.

This means you can have a fault with a toaster, but it trips when you use the kettle, as the more load the larger the difference in voltage neutral to earth.

For me as an electrician with a insulation tester easy, but for DIY person with no testers it can be very misleading. However step on is unplug every thing when not in use, as often switches do not switch neutral, so the less in circuit the easier to work out what is the problem.

Some times we are lucky, in my house saw the water in the outside light.

But some times it simply does not seem to make sense, my old house would not trip for 2 years, then trip regular for 2 weeks, then another 3 years no trip and no fault found, I would assume spikes on the supply, but all I could do was guess, even with the test gear never did find a fault.

After loosing a freezer full of food, when I wanted RCD protection with this house went all RCBO's so less on each circuit.

I did have a leak and the RCBO tripped for good reason, after leak cured found a socket had clearly been damaged I could see the deformed plastic when I removed, but often not that apparent. Sockets are cheap enough.

But you say disconnected so you need to look else where, mouse, spider or water can all cause a RCD to trip.

 

[JohnW2]

I did tell you! Yes it does. And it doesn't look like any of those pics. There is one trip, one reset button and a line of switches for the various circuits. It's what most people, me included, would call the 'fuse box', though there are no fuses, which is indeed why I put the phrase in inverted commas, Thank you JohnW2!

Yes, you did (tell us about the test button), and I admit thst I missed thst.

If the thing that is tripping (whatever it looks like) has a test button, then it is an RCD or RCBO (from your description, probably the former). As has been asked, can we have a photo of it or, failing that, could you tell us what is written on it?

Kind Regard's, John