sockets trip fuse box

[ted666]

Hi

This has been covered probably many times and I suspect I already know the answer, but justin case I've missed something:
Our downstairs sockets appear to be tripping the fuse box, not the main switch but just the one dedicated to the downstairs sockets, which had an RCD on it. We've unplugged everything with the one exception, the washing machine, which will involve a great deal of hassle to access the socket - so it may well be that. The thing is, it doesn't happen all the time. It started a week ago, we unplugged everything except washing machine, called an electrician, he couldn't find the fault but tested the box and eventually switched the RCD to the upstairs sockets and moved the downstairs fuse further along the board - if that makes any sense. That seemed to work for a week. Then, it started again,the fuse keeps tripping, but not immediately, it can stay on for hours and then trip all of a sudden. Now, it could well be the washing machine or its socket.but the fact that the switch trips on an irregular basis, I find confusing. The electrician we called isn't yet experienced in fault finding, but he thinks we should call someone in who can check the wiriing to isolate if there is a fault there...what's troubling is the fact that it does not happen all the time??
any thoughts?
cheers

 

[Aragorn84]

A photo of the board, indicating which device is tripping out would be useful!

 

[Adam_151]

What exactly is the device which keeps tripping, can you post a picture of your fuse-board with the offending device circled?

 

[ted666]

A photo of the board, indicating which device is tripping out would be useful!

Here's a photo of the tripped fuse box,third switch along is tripped. It was originally connected to the RCD on the left, but wehad it moved and it worked fine for a week..now it trips every few minutes, sometime

 

[mikeyd]

Here is a clickable view of your picture:

tripped fuse box

• ted666
• 1 Mar 2014
• 1

fuse box with the downstairs socket tripped

 

[JohnW2]

Here's a photo of the tripped fuse box,third switch along is tripped. It was originally connected to the RCD on the left, but wehad it moved and it worked fine for a week..now it trips every few minutes, sometime

Do I take it that the electrician simply moved the same MCB from the RCD to non-RCD side of the board? If so, although it's clearly impossible to give any answer without being there and doing testing, I would have thought that a faulty MCB was as likely a suspect as any - unlike the situation with RCDs, sporadic trips of non-faulty MCBs (whether 'spontaneous' or due to subtle faults) are not all that common.

You might suggest that the electrician swaps the two sockets circuits between the two MCBs - if its then still the same MCB (but then a different circuit) which keeps tripping, that would leave a finger pointed very firmly at the MCB itself.

Kind Regards, John

 

[FDJ]

Hi

The electrician we called isn't yet experienced in fault finding, but he thinks we should call someone in who can check the wiriing to isolate if there is a fault there...
cheers

I think you need a "proper" Electrician....
When dealing with an intermittent fault that you can't reproduce, you have to do "something" to try to eliminate one or more possible causes. Then go away and await the outcome.
I.e. swap the two breakers for the two circuits.
Moving the breaker to the non-RCD side has proved exactly nothing apart from the lack of knowledge of your "Electrician".
You need to get him to restore it to normal as your sockets are now not protected by the RCD.

Frank

 

[ted666]

Here's a photo of the tripped fuse box,third switch along is tripped. It was originally connected to the RCD on the left, but wehad it moved and it worked fine for a week..now it trips every few minutes, sometime

Do I take it that the electrician simply moved the same MCB from the RCD to non-RCD side of the board? If so, although it's clearly impossible to give any answer without being there and doing testing, I would have thought that a faulty MCB was as likely a suspect as any - unlike the situation with RCDs, sporadic trips of non-faulty MCBs (whether 'spontaneous' or due to subtle faults) are not all that common.

You might suggest that the electrician swaps the two sockets circuits between the two MCBs - if its then still the same MCB (but then a different circuit) which keeps tripping, that would leave a finger pointed very firmly at the MCB itself.

Kind Regards, John

Thanks John,
yep, the tripped MCB was indeed moved to its current position from the RCD on the left. the electrician checked if the RCD was faulty but cleared it. Which makes sense as the upstairs sockets it now protects are working fine.

I'm not sure if he actually checked the MCB itself though. I'm hoping this is the cause as tt would explain why we have this intermittent tripping. I'm loathed to start moving fittings such as washing machines etc from the kitchen units especially if its not the cause of the tripping. It really makes no sense otherwise to have an intermittent fault. i shall get on it...thanks again

 

[ted666]

Hi

The electrician we called isn't yet experienced in fault finding, but he thinks we should call someone in who can check the wiriing to isolate if there is a fault there...
cheers

I think you need a "proper" Electrician....
When dealing with an intermittent fault that you can't reproduce, you have to do "something" to try to eliminate one or more possible causes. Then go away and await the outcome.
I.e. swap the two breakers for the two circuits.
Moving the breaker to the non-RCD side has proved exactly nothing apart from the lack of knowledge of your "Electrician".
You need to get him to restore it to normal as your sockets are now not protected by the RCD.

Frank

Hi Frank

To be fair to the electrician - not a phrase I read often here - he did check the RCD and the system did work for a week before tripping again on Thursday evening. I'm hoping John's explanation of a faulty MCB is the cause of this intermittent fault.

best

T

 

[JohnW2]

I'm not sure if he actually checked the MCB itself though. I'm hoping this is the cause as tt would explain why we have this intermittent tripping. I'm loathed to start moving fittings such as washing machines etc from the kitchen units especially if its not the cause of the tripping. It really makes no sense otherwise to have an intermittent fault. i shall get on it...thanks again

As FDJ has said, a competent electrician really shouldn't need to have us offering these suggestions - but, as I said, swapping the circuits between the two MCBs would go a long way to narrowing down the cause of the problem. Unlike RCDs, MCBs cannot really be tested by an electrician.

As FDJ also said, this electrician has also left you (unnecessarily) with an undesirable, and potentially dangerous situation, since one of your sockets circuits no longer has RCD protection. I can't really think what was in his mind, since it is all-but-impossible (at least, for me!) to imagine any situation in which moving the MCB off that RCD would have made any difference!.

I would imagine that an electrician who knows what he's doing would probably be able to sort this out without too much trouble.

Kind Regards, John

 

[ted666]

Here's a photo of the tripped fuse box,third switch along is tripped. It was originally connected to the RCD on the left, but wehad it moved and it worked fine for a week..now it trips every few minutes, sometime

Do I take it that the electrician simply moved the same MCB from the RCD to non-RCD side of the board? If so, although it's clearly impossible to give any answer without being there and doing testing, I would have thought that a faulty MCB was as likely a suspect as any - unlike the situation with RCDs, sporadic trips of non-faulty MCBs (whether 'spontaneous' or due to subtle faults) are not all that common.

You might suggest that the electrician swaps the two sockets circuits between the two MCBs - if its then still the same MCB (but then a different circuit) which keeps tripping, that would leave a finger pointed very firmly at the MCB itself.

Kind Regards, John

Thanks John,
yep, the tripped MCB was indeed moved to its current position from the RCD on the left. the electrician checked if the RCD was faulty but cleared it. Which makes sense as the upstairs sockets it now protects are working fine.

I'm not sure if he actually checked the MCB itself though. I'm hoping this is the cause as tt would explain why we have this intermittent tripping. I'm loathed to start moving fittings such as washing machines etc from the kitchen units especially if its not the cause of the tripping. It really makes no sense otherwise to have an intermittent fault. i shall get on it...thanks again

Update: unfortunately, it appears that the electrician did not switch the MCB's itself, he switched the wires instead. IE: took the wiring from the upstairs sockets and fixed them to the RCD protected MCB and so forth. Meaning if the MCB was faulty it would have tripped the sockets upstairs which it hasn't. Blast. looks like i shall have to dismantle kitchen units and check the socket behind washing machine after all.....

 

[JohnW2]

Update: unfortunately, it appears that the electrician did not switch the MCB's itself, he switched the wires instead. IE: took the wiring from the upstairs sockets and fixed them to the RCD protected MCB and so forth. Meaning if the MCB was faulty it would have tripped the sockets upstairs which it hasn't. Blast. looks like i shall have to dismantle kitchen units and check the socket behind washing machine after all.....

Ah - that's obviously what I was suggesting should have been done as a test. However, are you now saying that the MCB which is shown tripped in your photo has not been physically moved - such that one of your sockets circuits (I presume the upstairs one) never had RCD protection?

Whatever, if what you now say is correct then, yes, you will obviously have to continue looking for causes in the downstairs sockets circuit - and, although it may not be the culprit, disconnecting the washing machine from the circuit would be the first thing to do, if only to 'eliminate' it.

It is still all a bit odd. For a washing machine (or anything else, come to that) to result in intermittent tripping of a non-faulty MCB (but not the RCD also in the circuit) would be pretty unusual.

Kind Regards, John

 

[ted666]

Update: unfortunately, it appears that the electrician did not switch the MCB's itself, he switched the wires instead. IE: took the wiring from the upstairs sockets and fixed them to the RCD protected MCB and so forth. Meaning if the MCB was faulty it would have tripped the sockets upstairs which it hasn't. Blast. looks like i shall have to dismantle kitchen units and check the socket behind washing machine after all.....

Ah - that's obviously what I was suggesting should have been done as a test. However, are you now saying that the MCB which is shown tripped in your photo has not been physically moved - such that one of your sockets circuits (I presume the upstairs one) never had RCD protection?

Whatever, if what you now say is correct then, yes, you will obviously have to continue looking for causes in the downstairs sockets circuit - and, although it may not be the culprit, disconnecting the washing machine from the circuit would be the first thing to do, if only to 'eliminate' it.

It is still all a bit odd. For a washing machine (or anything else, come to that) to result in intermittent tripping of a non-faulty MCB (but not the RCD also in the circuit) would be pretty unusual.

Kind Regards, John

Indeed. Unusual and frustrating. Its the worst case scenario when you have an intermittent anything: on a car, pc, or as in this case wiring, as pinpointing the fault looks like being a lottery and a great deal of hassle - which is why im still typing instead of kneeling on the floor unscrewing cupboards - again: in defence of the electrician, he did inform me he was not yet experienced in fault finding, but he knows what he's doing and more to the point, trustworthy. he is young and did say we should get a more experienced electrician with testing equipment, but seeing as though everything was working fine, i didn't see the rush...ho hum. Besides, does it make any difference which MCB the RCD protects? Surely there is no difference between the upstairs or downstairs sockets?
regards
T

 

[JohnW2]

Indeed. Unusual and frustrating. Its the worst case scenario when you have an intermittent anything: on a car, pc, or as in this case wiring, as pinpointing the fault looks like being a lottery and a great deal of hassle - which is why im still typing instead of kneeling on the floor unscrewing cupboards

Indeed. The electrically unusual thing about this is that, unlike the tiny 'leaks' which can cause RCDs to trip, it takes a lot of current to cause a 32A MCB to trip - more often that not enough to make something 'go bang' - so unexplained intermittent/random tripping of MCBs is unusual.

- again: in defence of the electrician, he did inform me he was not yet experienced in fault finding, but he knows what he's doing and more to the point, trustworthy. he is young and did say we should get a more experienced electrician with testing equipment, but seeing as though everything was working fine, i didn't see the rush...ho hum.

Fair enough. It's good to hear that he understood and acknowledged his limitations. I'm far less critical now that you've indicated that he swapped the circuits between MCBs - as I'd been saying, that was a far more reasonable diagnostic test than what you originally suggested he had done.

Besides, does it make any difference which MCB the RCD protects? Surely there is no difference between the upstairs or downstairs sockets?

I suppose that the only real difference it really makes is whether you're more likely to be upstairs or downstairs if/when you suffer a fatal shock from a circuit which is not RCD protected Ideally, you obviously should have RCD protection of all sockets - that's essentially what is now required by regulations (for new circuits).

Kind Regards, John

 

[planenut]

Blast. looks like i shall have to dismantle kitchen units and check the socket behind washing machine after all.....

Perhaps it would be a good idea to be able to isolate the washing machine without having to pull it out for future emergencies? regardless of whether it is the fault.