MCB Tripping Fault

[flyingsparks]

Hi. At home I have a 5A MCB on a lighting circuit which keeps tripping out. Even when all the lights on that circuit are off, it will occasionally trip. I therefore gather there is an earth leakage. I am going to megger the circuit. Any advice would be appreciated.

Many Thanks

Flying SParks

 

[andy]

is there an RCD there?

when doing insulation tests remember to remove all the bulbs

EDIT: just because the MCB keeps trippin, it doent mean its an earth leak. it could be a phase to neutral leak

 

[Lectrician]

Any outdoor PIR lighting - start there.

 

[kendor]

Also it may just be a mechanical fault with the latching of the MCB, especially so if no current flow is observed when you test the circuit. new MCB needed if so.

 

[ban-all-sheds]

That's one heck of a "leak" to trip an MCB, even a 5A, (which probably implies a Type 1??)

The word "fault" or "short circuit" might be more appropriate...

Also you say "Even when all the lights on that circuit are off, it will occasionally trip" - anything else on the circuit? Fan? Shaver socket?

 

[flyingsparks]

Hi Everyone. Thanks for all your replies. I could hear where the fault was (loud popping noise), so I have lifted the floor boards, and found a cable eaten by the bloody mice!! Replace it now - all working fine!

Cheers Chris

 

[breezer]

theyll be back

 

[plugwash]

should've given them some nice SWA or pyro to chew on

 

[andy]

either that or remove the MCB so they fry (along with the house)

NOTE: i do not recommend this

 

[ninebob]

either that or remove the MCB so they fry (along with the house)

NOTE: i do not recommend this

I find that having a cat works quite well!

 

[flyingsparks]

either that or remove the MCB so they fry (along with the house)

NOTE: i do not recommend this

I find that having a cat works quite well!

My dog is quite good at it to!

 

[ban-all-sheds]

either that or remove the MCB so they fry (along with the house)

NOTE: i do not recommend this

I find that having a cat works quite well!

It's a real b*gger to keep them under the floorboards though.