Mcb tripping.

Mrcaramelchoc

One of the mcbs on the fuse board keeps tripping.we ve narrowed it down to a bunch of sockets in one part of the house.
Electrician came And he opened up every socket in the house and couldn't find any fault.
He ended up saying he couldn't fix it that it would need a sparky with special equipment to find the fault.
Would anyone like to explain this to me properly?please.

Luckysasha

Not much of an electrician!!!! Id say he just didn’t want to spend the time fault hunting. Sounds like a cable fault between sockets or quite possibly a faulty MCB

Mrcaramelchoc

Luckysasha wrote: »

Not much of an electrician!!!! Id say he just didn’t want to spend the time fault hunting. Sounds like a cable fault between sockets or quite possibly a faulty MCB

Yea.he was of the opinion that it wasnt the mcb.how would a fault like that normally be found or what would it be.a loose connection or a broken wire?

salmocab

Is it an mcb tripping or the rcd? Stuff like this notoriously difficult to find the fault in especially if it’s intermittent.

Mrcaramelchoc

salmocab wrote: »

Is it an mcb tripping or the rcd? Stuff like this notoriously difficult to find the fault in especially if it’s intermittent.

Its definitely the mcb.i suppose ill be getting a different electrician but id like to be a bit clued in.is there specialist equipment for this kind of fault finding?

salmocab

Mrcaramelchoc wrote: »

Its definitely the mcb.i suppose ill be getting a different electrician but id like to be a bit clued in.is there specialist equipment for this kind of fault finding?

It’s very hard to say what he’ll need, might need a multi-tester/merger which is more the sort of equipment a company has and uses for testing installations. It does more than the multimeter that most sparks would have in their tool boxes. It’s a pig to find faults especially if they are only intermittent and if the fault doesn’t exist whilst the spark is there he may not find it or maybe his meter will show something up. There is an element of luck too sometimes, you happen to look at something from the right angle and spot a nick in the sheath that the last guy didn’t see.

Mrcaramelchoc

Would i be right in saying that if it was the mcb causing the problem,the only way you'd know is by replacing it?

_Brian

He could swap the mcb with a same rated one on the board, if the fault moves it’s the mcb, if the fault stays on that circuit then it’s not the mcb but a cable issue.


Then I’d start removing the sockets one by one terminating cables safely and see if any of them have a fault.

salmocab

Mrcaramelchoc wrote: »

Would i be right in saying that if it was the mcb causing the problem,the only way you'd know is by replacing it?

No as Brian says he can swap the circuit onto a different mcb, if the same mcb trips it would indicate the mcb is faulty but if the mcb that has been moved to trips then it’s the circuit.
How often does the mcb trip?

2011

The tripping MCB issue can be resolved by process of elimination without any test equipment. Let me explain:
For example if the MCB is disconnected from the circuit and it still trips then the MCB is faulty, if not (most likely) the fault is on the circuit the MCB supplies.
If the MCB stays on when the last ½ of the circuit is disconnected then the problem is in the disconnected part of the circuit etc.

Time to get another electrician.

Besides it does not bode well if an electrician turns up to fix a fault without test equipment.

Risteard81

Frankly it's laughable that he would describe electrical test instruments as specialist equipment, given that all electrical installation work needs to be verified with such instruments. Although it's certainly possible that a fault could be intermittent, I would suggest that there is a high likelihood of identifying the fault with the correct equipment and knowledge of how to use it.

Luckysasha

If its a ring main id split the ring at the halfway point. Then take one leg out of the MCB including the neutral and try reset the MCB. Other option is to take tails out of the mcb and megger the circuit. Any decent spark should be ableto do this. Just one more thing OP have you everything plugged out of the sockets when it’s tripping. Bear in mind there could be a sneaky spur somewhere hidden by a press or such likes

Mrcaramelchoc

_Brian wrote: »

He could swap the mcb with a same rated one on the board, if the fault moves it’s the mcb, if the fault stays on that circuit then it’s not the mcb but a cable issue.


Then I’d start removing the sockets one by one terminating cables safely and see if any of them have a fault.

He actually did swap them now that i recall and the fault stayed where it was.

Mrcaramelchoc

Luckysasha wrote: »

If its a ring main id split the ring at the halfway point. Then take one leg out of the MCB including the neutral and try reset the MCB. Other option is to take tails out of the mcb and megger the circuit. Any decent spark should be able to do this. Just one more thing OP have you everything plugged out of the sockets when it’s tripping. Bear in mind there could be a sneaky spur somewhere hidden by a press or such likes

Yes every thing plugged out in the house while doing it.in fairness to the guy he did everything he could and admitted it was beyond him.if that makes him a bad sparky fair enough im not in a position to say if he is or not as im not an electrician.

salmocab

Is it tripping constantly as in won’t stay on at all or how often does it happen?

Mrcaramelchoc

salmocab wrote: »

Is it tripping constantly as in won’t stay on at all or how often does it happen?

Constantly.it will not stay on.

salmocab

It’s likely a dead short I would think, which should be relatively easy to find (or at least identify the loop that it’s on) I presume you haven’t carried out any work in the house recently like renovations or a new boiler etc

Mrcaramelchoc

salmocab wrote: »

It’s likely a dead short I would think, which should be relatively easy to find (or at least identify the loop that it’s on) I presume you haven’t carried out any work in the house recently like renovations or a new boiler etc

No nothing.and like i said this happens even when everything in the house is plugged out.he even disconnected the boiler.

salmocab

When did it start happening? Is it tripping constantly since it started or did it get progressively worse to the point where it won’t stay on?

Mrcaramelchoc

salmocab wrote: »

When did it start happening? Is it tripping constantly since it started or did it get progressively worse to the point where it won’t stay on?

Its always been constant. it happened on wednesday last.my wife thought it was the charger she plugged in but that wasn't the case.

salmocab

Mrcaramelchoc wrote: »

Its always been constant. it happened on wednesday last.my wife thought it was the charger she plugged in but that wasn't the case.

Honestly it should be easy enough to identify the leg with the issue if it’s constant and only happened last week.

Mrcaramelchoc

salmocab wrote: »

Honestly it should be easy enough to identify the leg with the issue if it’s constant and only happened last week.

I presume you mean easy for a qualified sparky right?

salmocab

Mrcaramelchoc wrote: »

I presume you mean easy for a qualified sparky right?

Oh yeah sorry

Mrcaramelchoc

I got a second electrician.he came and tested Each socket with a fairly sophisticated looking multimeter.he found nothing.he took off the fuse board cover and looked tested that and nothing.he turned it all back on and its been working fine since.
It hasn't tripped since.crazy.