sockets gone off

[debzo]

Hi - new to the site - but been away for a week, came back in the middle of the night to find sockets had tripped on ground floor - freezer defrosted + usual clean up needed. checked mcb and flicked it back on - but it sparked and clicked off after short delay. Took all appliances etc out . Still tripped. Took ring out and tried each leg individually in mcb - but both sides trip. How do i find out what is causing the tripping?

 

[ricicle]

As the circuit is a ring, taking out each leg will not make any difference.
Have you done any DIY recently (hanging pictures etc) or could there be a leak anywhere (rain/pipework) ?
If the MCB trips back out every time then there is a pretty constant fault which shouldnt be too hard to find.
If simple checks do not prove anything you will most probably need the services of a competant professional to fault find for you.

You could try keeping the circuit isolated and checking behind all the sockets for trapped cables or water ingress...

 

[BigJon]

Have you double checked there is nothing plugged in, when you say after a short delay it makes me think an appliance or something is turning on then tripping.
Is circuit on an RCD, does MCB hold when you have no load connected.
You could trace the cable run out with a multimeter/insulation resistance meter and check if cables are clear if you have one.

 

[debzo]

Have you double checked there is nothing plugged in, when you say after a short delay it makes me think an appliance or something is turning on then tripping.
Is circuit on an RCD, does MCB hold when you have no load connected.
You could trace the cable run out with a multimeter/insulation resistance meter and check if cables are clear if you have one.

Circuit is not on RCD - there is nothing plugged in to the circuit - checked it 3 times; when I say a short time I really mean it delays by between 10 seconds and approx 30 seconds rather than flicking off immediately - also the MCB sparks when it trips - I tried the circuit in a different MCB and it trips the same. The circuit is a mix of floor and switched wall sockets.

I have just bought a digital multimeter, but don't yet know how to use it for this - the instructions don't make much sense to a layman! any help here would be welcome.

 

[debzo]

As the circuit is a ring, taking out each leg will not make any difference.
Have you done any DIY recently (hanging pictures etc) or could there be a leak anywhere (rain/pipework) ?
If the MCB trips back out every time then there is a pretty constant fault which shouldnt be too hard to find.
If simple checks do not prove anything you will most probably need the services of a competant professional to fault find for you.

You could try keeping the circuit isolated and checking behind all the sockets for trapped cables or water ingress...

I was away for the last 4 days - came home in middle of night to find system tripped. Nothing been done at all - unless the mice have moved in for winter!!

 

[1john]

Sure the central heating is connected via a fused spur to this circuit??

Why did you try each end of the ring individually?

 

[Taylortwocities]

Are you sure the device that is tripping is am MCB and not something else, like an RCBO.?

HAs it got a test button on it. A picture would be good.

This may help

Untitled

• Taylortwocities
• 27 Mar 2010
• 43

 

[mfarrow]

It's quite possibly a short circuit somewhere - I had one that took between 5 second and 8 hours to trip - used to take out both the MCB and RCD.

If there's sparks coming out the device then I suspect it's trying to break fault current rather than load current (which we've been told there's zero) + a little leakage current.

If you're feeling competent then do as suggested and have a look behind sockets etc. Otherwise an IR test should reveal all.

 

[Taylortwocities]

If you're feeling competent then do as suggested and have a look behind sockets etc. Otherwise an IR test should reveal all.

He has admitted that he does not not know how to use a multimeter so an Insulation Resistance test might be sretching his level of competence (no shame attached, BTW).

I agree a good visual check is worthwhile, with the power off. Then you may need someone on site.

 

[debzo]

If you're feeling competent then do as suggested and have a look behind sockets etc. Otherwise an IR test should reveal all.

He has admitted that he does not not know how to use a multimeter so an Insulation Resistance test might be sretching his level of competence (no shame attached, BTW).

I agree a good visual check is worthwhile, with the power off. Then you may need someone on site.

Hi all thanks for input - have been reading up on multimeters this morning - so will now do the following:

CU off - pull each socket and check behind then test for continuity - the ring that has gone down has 10 sockets in total and fortunately I know the beginning of the ring, so my theory is to test continuity at each stage - with my new found understanding of the multimeter!

There is nothing connected to the circuit - the CH has its own circuit, as does the kitchen - this one had lamps and TV etc which are all unplugged, so am hoping the fault is behind a socket and not between long hidden cables - as we have stone floors virtually throughout.

 

[debzo]

Sure the central heating is connected via a fused spur to this circuit??

Why did you try each end of the ring individually?

Wanted to see if it was a ring and not 2 radial circuits - was that dumb?

 

[ban-all-sheds]

It's not the way to verify that it is, or is not, a ring - you check that by checking end to end continuity.

If you have a break in either L or N somewhere, disconnecting one end would make some sockets appear dead but would not mean you had 2 radials. Or, depending on what the fault is, and where, a break might also make you think you had 2 radials because the fault goes away.

Do you know the route the cables take?

 

[debzo]

It's not the way to verify that it is, or is not, a ring - you check that by checking end to end continuity.

If you have a break in either L or N somewhere, disconnecting one end would make some sockets appear dead but would not mean you had 2 radials. Or, depending on what the fault is, and where, a break might also make you think you had 2 radials because the fault goes away.

Do you know the route the cables take?

I am almost through on the cable route - what a fun way to spend Sunday!! Found one floor socket in conservatory that had water near it and moisture in the terminals - I was told we had had a down pour on Thursday so am thinking the conservatory roof might have leaked - once I have finished the route I will test again and if all well then chuck the hose pipe onto the glass roof to see any leaks - or it could have been an eager partner being over zealous with watering the excuse of tomato plants he thinks will produce more crop!!! Thanks for all advice so far, will let you know the end result - sometime near midnight I guess!!!

 

[debzo]

O.k all sorted - circuit back to normal. Thanks for all the advice. Might have a go at tracing an auto electrical gremlin next weekend!!

 

[ban-all-sheds]

It's not the way to verify that it is, or is not, a ring - you check that by checking end to end continuity.

Would the person who gave my post a thumbs down please explain why what I wrote there was incorrect?

If you have a break in either L or N somewhere, disconnecting one end would make some sockets appear dead but would not mean you had 2 radials. Or, depending on what the fault is, and where, a break might also make you think you had 2 radials because the fault goes away.

And this, please.

Do you know the route the cables take?

A reasoned explanation of why I should not have asked that question would also be appreciated.