Breaker tripping

[highspark]

Lads odd fault.

Breaker trips 20 mins-1 hour after being switched back on. 32 amp ring, old wylex board with push fit circuit breaker. Wiring is a mess. Ring is for sockets. It has exterior lights, alarm, boiler , attic lights, pond pump and fountain - all from jb's in attic - thoughts definate overload. Problem is I've unplugged everything and it's still tripping. There's a load bang in the attic everytime it trips. Any thoughts?

 

[highspark]

There must be something tripping it though. Just don't understand at all. It's a proper mess it NEEDS a rewire bur customer - old woman - "couldn't cope with it" it's an absolute joke!

 

[SimpleSimon]

It could turn unlikely that you may find the fault.
she may not be able to cope with a rewire but can she cope with the intermitent tripping??
heres a far fetched idea. A rodent has chewed through the cable (we all know how those little b#%&&ds love to) whilist chewing through it has died through an electric shock with the cable still in its mouth thus completing the curcuit. This is way fsr fetched but ive known it to happen. I like to think outside the box.

Sent from my GT-I9100 using Tapatalk

 

[highspark]

I'd like 2 split onto 2 radials but no spare ways in a board. It's an old wylex 4 way board

 

[highspark]

Why though lads if everything is unplugged is it tripping after 3 hours. There's no load on the circuit!!! And if there was a short circuit it would constantly trip instantaneously. The breaker has been changed 3 times so it's not a dodgy breaker. This is the ultimate puzzle. How about the 0.01mohm readings lads. A major fail somewhere.

 

[UKMeterman]

0.01Mohm this could be the carbon trace. There is a way to help find the fault but not cheap, I suspect that some of the power anlyzers such as the Fluke 43 could indicate that the fault current has passed a certain location...! Split the circuit in half at the CU and then split it either side of the loft and test. If need be just run some t&e across the loft bypassing some of the problem and just divide again and again..

 

[Rockingit]

How confident are you that everything is indeed, 'off'. Have you clamped the circuit at the DB to actually check it's drawing 0.00A? My guess is either rain in an outside light or rodents - I once spent hours chasing a popping light circuit and it was a dead spider inside the pendant!!

 

[highspark]

I've clamped it and yes it's all definitely off.

Why the he'll is it lasting for 3 hours then popping..... With everything unplugged!!!!!

For 3 hours it's ok the bang on time it's off!

I feel stupid not isolating it now. I've done all IR's, clamp metered it and inspected jb,s and cable where I can! But still nothing!

 

[GLENNSPARK]

I've clamped it and yes it's all definitely off.

Why the he'll is it lasting for 3 hours then popping..... With everything unplugged!!!!!

For 3 hours it's ok the bang on time it's off!

I feel stupid not isolating it now. I've done all IR's, clamp metered it and inspected jb,s and cable where I can! But still nothing!

you say "bang on 3 hours".....like somethings timed or summat but you also say you clamped it and its definately off?.....what type of heating system is here? Y plan? salamander box?..so like you dont have any current draw .....until the y plan operates that is (which wont use owt much anyway) and.......

 

[hyperloop]

Ive had a similar scenario in the end had to test each section of the ring to find - a bit long winded but better than trying something and hoping for the best each time then getting the dreaded call.....

 

[Rockingit]

Just a thought - have you disconnected the circuit directly at the breaker then left the breaker on? Sounds silly, but at least it would discount the mcb itself.

another thought - is this on a split board? might have a shared neutral issue

 

[Octopus]

I's split the ring in half,fit a 16A breaker and leave 1 half connected and see what happens, then try the other half.

Sounds like a "nice" fault to have - can the customer afford your time?

I have to admit that the "bang" does sound interesting!

 

[highspark]

I split it today where I thought was tge centre of the ring only one breaker tripped but it seems to have taken out more than half of the circuit. It's only a 4 way board no spare was etc. It's a bloody nightmare. At first customer was getting 20 mins then it was tripping. Now he's getting 3 hours - since I've opened up jb's etc. My problem is what the hell is allowing it to be on for 3 hours and then tripping if everything is unplugged and it's not an overload!

 

[hyperloop]

dont forget tripping will take time if theres a IR fault not serious enough to cause instant tripping - check out operating times in 7671. And the fault is constant so will take same time every time to occur. Must trace it through testing each leg of the ring.

 

[UKMeterman]

Hi,
If it is tripping after 3 hours on THERMAL overload and this is 32A breaker there is a lot of power going somewhere! I would suspect some kind of arc over instead, causing a short.

 

[Rockingit]

Do you know anyone with a thermal camera that you could beg/borrow/rent/steal? That energy has to be dissipating itself as heat, so it probably wouldn't take long to track down with an IR scope, even a 'cheap' one.