Breaker tripping

[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.