bulb popped the cu but then back on..

[AfterSomeAdvice]

Hi,

When I came back from work I turned the light on and the breaker in the cu went. I turned it back on. I then turned the switch on and the bulb works. The bulb is one of those long energy bulbs.

i am a little worried about this. The light circuit is on a 6amp ring. The system is a year old. Its never done this before.

What could be the cause?

 

[Spark123]

What is written on the device which tripped?
Is there any sign of water getting in? Was there any noise from the switch as you operated it - I have seen 4 lug boxes short to the common of a single way light switch before.
Lighting isn't normally wired as a ring - it is usually radial.

 

[AfterSomeAdvice]

not sure what you mean by 4 lug boxes.

 

[AfterSomeAdvice]

what an idiot i am!!!

Just realized it is another light thats blown!!! The bulbs gone and it is a normal 60w bulb.

Sorry for the bother. BTW, is it ok for a circuit to trip if a bulb blows?

 

[rebuke]

Perfectly normal for an MCB (Miniature Circuit Breaker) to trip when a bulb blows - very briefly there will be a very large short circuit current, which is enough to trip the breaker...

 

[JohnD]

the MCB tripping is particularly common with spotlights and other non-standard bulbs. Some people say it happens less with a premium quality lamp like Osram.

It happens a lot more if you have e.g. a kitchen with large numbers of spotlights or downlighters, as with more lamps, you will obviously have more failures per year.

Compact Fluorescent lamps (energy saving) do not cause this problem, as they do not have a filament which can cause a surge when it fails.