U.K. only. When a bulb goes in my house, the fuse blows as well. Why?

Question

I have lived around different places around the UK and have never experienced anything like this before.

Answer 1

I am assuming that by 'fuse blows' you mean 'breaker trips'???? When the lamp fails (shorts) there is a surge and this is causing the MCB to trip, change the circuit breaker from a type 'B' to a type 'C' which is not as sensitive to these type of transient faults. Sometimes a lamp will fail without shorting, i.e. the filament just breaks, this does not cause the breaker to trip. Rewireable fuses are not nearly as sensitive as circuit breakers, which is why you have not experienced this before.

Answer 2

Q. Why does it do it?
A. When the bulb "blows" there is a sudden spike in current as the filament burn out which exceeds the trip threshhold. It can also be caused as the free live end of the filament "springs back" at the point of breaking and touches other metal parts of the lamp interior also causing current spikes.
Q. How do I overcome this?
A. If you have and RCD/RCCB and that trips there's nothing you can do about it. If you have an old-fashioned fusebox with wire fuses I'd suggest upgrading it so that all you have to de is re-set the trips. You don't necessarily have to replace the whole "consumer unit" as you can get plug-up cartridge circuit breakers that are a standard replacement for the classic fuseholder (look for "type B" circuit breakers on www.screwfix.com)

Answer 3

Limited info there mate email me if this answer does not do the trick.

Firstly if it is an old style fuse box, looks like brown or black plastic, then check the fuses are are correct rating. If the fuse box is a new style it just may need the trip switch pushing. The new one's have a very tight range for safety.

Other thing may be too many halogen lights they can blow fuses. DO NOT put OVER RATED fuses in it will cause a fire!

Like I said though if you have no luck just email me and I will try to help you.

Answer 4

If they are spot lights or down lights this often happens if it's just a normal bulb there may be a fault with your fuse box
It's a good job the fuse blows really, because if it didn't it could cause your home to catch fire

Answer 5

Its a characteristic of the trip switch with tungsten filament lamps. Why not try replacing with energy saving lamps,they don't effect the mcb & save you money in long run. If you have a lot of fancy fittings which can only be used with tungsten lamps then change the mcb for a type c instead of a type b.This will eliminate this problem too.

Answer 6

It in it's last gasp, spikes and draws an arc, of sudden high amperage, and temperature at the fuse link, try slow blow type fuses, that can absorb the shock current, but will still provide a safe circuit.

Answer 7

I had the same problem a few months back and it turned out to be the cable to the light it had a slight nick and hole in it and the wire was exposed causing an arc. Soon as the length of cable was replace no more problems.

£50 Tops to repair. Lets hope it is something as simple as that.

Answer 8

If you have circuit breakers, then that's normal, if on the other hand you have fuse's and have to replace the fuse then you have a wiring problem and you need to get an electrician out to check your wiring.

Answer 9

A lot of houses do this.

I think its to do with cheaper bulbs adn MCB sensitivity. Expensive bulbs have element shields so they do not short out when the element breaks. Std bulbs from Tesco, wilko etc do not have this.

energy savers now come in std shapes so we are all likely to buy those over the enxt few years, this will cure your problem.

Answer 10

If its a new fuse board in the house it will be fitted with a RCD, this is designed to trip in the event of any electrical fault. If it is an old style fuse board most likely to be a wiring fault.