DIYbanter - View Single Post - When bulb blows, earth leakage circuit breaker is tripped

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wrote:
wrote:

I suspect you don't mean earth leakage trips..its uncommon to have those
on lighting circuits alone..

Yes, its very common for bulbs to trip a standard MCB.. as they arc on
failure and draw quite large currents before burning out. Mine do it
every time..I s'pose I could replace then with slower acting ones..but I
can't be arsed..

Out of interest, how do they specify slower acting ones ? I've never
seen them, but then for a twice-a-year event (the MCB tripping on bulb
blowing) I also fall into the CBA category ...

Type C instead of te more common type B. A bit less prone to nuisance
trips.

AIUI though, the reason for the trip is just before the filament blows,
an arc is created, which has a very low (almost infintesimal)
resistance which leads to the current draw being astronomical (almost
infinite) certainly in excess of 200A.

It's the speed that the MCB reacts with that causes the trip. I would
have though that even a type C would trip when a bulb blew ?