MCB trip not resetting

[GrahamT]

Hi

My lighting circuit MCB tripped last night when a bulb blew. When I went to reset it after replacing the bulb, it wouldn't stay in the up position.
There doesn't seem to be the same physical resistance when I move the switch and it just falls back to the down position.

Anyone know what the problem is? any advice, much appreciated.

Regards,

Graham

 

[1john]

one of two things, there is a fault still present or the mcb is shot and needs replacing.

 

[GrahamT]

the mcb is shot and needs replacing.

Is that an easy job? does it just pull out and click back in?

 

[sparkwright]

What make is it and how old do you think it may be?

 

[sparkwright]

Have you tried removing the bulb and leaving the light switch in the off position?

Does the wiring at the lampholder look healthy? Perhaps changing the bulb has disturbed a bad connection.

 

[GrahamT]

What make is it and how old do you think it may be?

Protec. I seem to remember this might have happened before, a couple of years ago, but can't be sure it was the 6A circuit. Generally, the consumer unit looks fairly new - we've lived here for almost 4 years and it was here when we arrived

 

[GrahamT]

Have you tried removing the bulb and leaving the light switch in the off position?

Does the wiring at the lampholder look healthy? Perhaps changing the bulb has disturbed a bad connection.

Currently, I have left the bulb out.

 

[sparkwright]

You may struggle getting one of those on a Sunday.

Don't know what other makes would fit.

Could be a fault with the wiring.

Do you have another 6 amp lighting circuit mcb in the board?

 

[GrahamT]

We can hold out for another day using lamps on the ring main. I know screwfix do MK, Crabtree, Volex, Wylex. But I can go to merchants tomorrow for Protec one.

My main question is whether this is easy to replace. I'm a heating engineer, so not a total spanner with my hands, but I have a healthy respect of electrics (i.e. I rarely do any apart from wiring in boilers, pumps etc.)

And no, there isn't another 6A MCB

 

[mikhailfaradayski]

is it possible for you to remove the wire ( carefully, whilst power is off) that comes from the suspect mcb, then restore the power and see if the trip will reset?

 

[holmslaw]

..

 

[securespark]

Isn't that RCD's?

I've only replaced 3 faulty MCB's in recent years: two were Protek and one Contactum.

If the board is not old, contact Protek and ask for a replacement in the post. Explain how old your board is and they should send you one FOC.

That's what I did.

 

[Taylortwocities]

Protek?

Isn't that RCD's?

I've only replaced 3 faulty MCB's in recent years: two were Protek and one Contactum.

Funny thing. I have changed two faulty MCBs this week (at different sites)

Both were MK B6's. One had stripped clamp on output so bad contact to lighting circuit, the second was the same fault as the OP's - floppy lever.

 

[Spark123]

Switch the main switch off and see if it will reset. If it doesn't then the MCB is shot.

 

[kai]

Won't that fault suggest that the MCB breaker has interrupted a very large short circuit current, and has destroyed the internal mechanism?? - this is one possible explanation - the lever failing to reset is an indicating device to tell you to buy a new one.