MCB arcing

[peanut125]

Hi, this is my 1st post and i'm not an electrician or anything so i'll apologise for saying anything stupid now.
My supply went a bit mad today tripping out about a dozen times in 30 mins. I had a look and the mcb on the consumer unit was arcing. It didn't actually trip but the supply kept cutting in/out. It has since stopped and seems to be fine and when this was happening there was no smell of burning or heat build up.
Is it safe to leave it and just keep an eye on it since it seems fine now or do i need to have the breaker replaced. If so who do i call as the main fuses are sealed so i cant isolate the power to the breaker.
Cheers

 

[Click-Sure]

Sounds like you have yourself a problem there. Were you doing anything unusual when this occoured? Just because its working now could mean that the contacts inside the MCB have welded themselves together - essensially meaning that you could have not overcurrent protection on that circuit at all!.

By main fuses you mean the suppliers fuse on the supply head? These are supposed to be sealed and should only be cut by the electricity supply company, some of these companies are sympathetic to qualified electricians cutting these seals, but thats another story.

To change an MCB, isolation at the main switch is sufficient in most cases.

I suggest you flick the main switch off and get an electrician in - best to be safe than sorry! Post some pictures of your consumer unit so that we can give some clearer advice.

 

[peanut125]

I cant get any pics up at the mo but it has started playing up again. The supply comes in through the suppliers fuses which are sealed. Then it goes into the meter and then into the cinsumer unit. It is the main switch in the consumer unit that is at fault so it cant be isolated unless the fuses are taken out i think. Would it be my supplier eg western power distribution who would need to do this or british gas etc who i get billed by? thanks

 

[Click-Sure]

WPD will pull your service fuses for you, they should have an emergency number on their website.

 

[peanut125]

cheers have called them and they will cut the power. Will call an electrician and get it sorted. Thanks for the help

 

[Adam_151]

Would call the electrician first, its very unlikely that isolation on the suppliers side will be needed unless something is amiss!

(its quite normal for electricians to use the incommer of a board to achieve isolation when changing outgoing devices, the incomming terminals are normally pretty well shrouded)

 

[industryspark]

would agree on calling the electrician first would be the play.....he can advise on calling the suppliers i would think (he might even pull the suppliers fuse himself! )

adam, think the poster has problems with the main switch of the CU by the sounds of it, not just an mcb as suggested in the post title.