Tripped MCB

[Jonnyboy 68]

Hello again all,

Whats the technical answer....

Bulb blows / fails and the MCB trips knocking out everything on the circuit until a good un is put back in...

Why ?

It doesn't happen on new houses but I've occasionally heard of it on older ones..... :z

 

[Andy™]

because its normally a B type, and the high amount of flowing current trips it...

alternative is C6 or B10

 

[PC Electrics]

It's 'cos at the point of failure there is a massive inrush of current as the filament fails and vapourises. A plasma is created inside the bulb which is highly conductive.

The inrush is very short but it is often within the parameters of a B6s fault detection curve and so the MCB 'percieves' the inrush as a fault developing and trips.

Fit a C6 or B10 (Zs permitting) to provide a cure.

 

[Evans Electric]

PC said it all. The downside of using MCBs , it doesn't happen with HRC fuses but no one wants to use them anymore.

 

[Sidewinder]

Bulb blows / fails and the MCB trips knocking out everything on the circuit until a good un is put back in...

The bulk of this has already been explained.

However, there is one thing that remains, are you sure that the MCB cannot be reset until the lamp is replaced?

BTW, bulbs grow, lamps glow.

If so, this could be due to the failure of the lamp element causing the support wires to collapse and allow the input filaments to short thus making the lamp a dead short. This however is quite rare.

Generally the guys above are spot on, mind, no guarantees with the other mcb's just more chance of them staying in.

 

[Jonnyboy 68]

Cheers lads.. thanks for that

An Sidewinder ... You've also answered the question as to why all those 50w halogens I planted under the old cherry tree have done nothing for the past few years !!! LOL

HaHa ... spot on mate ! ROTFWLROTFWLROTFWL

 

[Badger]

Cheers lads.. thanks for thatAn Sidewinder ... You've also answered the question as to why all those 50w halogens I planted under the old cherry tree have done nothing for the past few years !!! LOL

HaHa ... spot on mate ! ROTFWLROTFWLROTFWL

you see mate we do give illuminating answers when required :slap :slap