I have two lighting circuits ,one covering the Hall,Back BR ,Kitchen
and Bathroom .The other covers the Front BR,LR and LR Cupboard .
Yesterday I found the Front Bedroom light wasn't working and checking
the circuit breaker ( Wylex Plug in type) and found it was in the off
position .Thinking the bulb had blown and caused this I turned the
breaker on but it immediately went pop and went off .I did it again
with same result .I then checked the wall switches,a couple of juction
boxes in that circuit and then checked the lampholders and found
nothing wrong. I did notice that in the lampholder in the LR
cupboard the lamp could be moved from side to side and wasn't being
held properly .It was one of them curlywurly low energy lamps so I
took the opportunity to change it for a "normal" bulb .I then tried
the circuit breaker and all was well. All the bulbs were checked and
found to be working .
I am going to change that lampholder when I get a new one but is it
possible that has been the cause of the fault...is it possible the
bulb was sitting with only one of the contacts "making contact" .Could
that cause the CB to trip? I was removing some stuff out the cupboard
so may have knocked it on my way out...

Usenet Nutter expressed precisely :
I am going to change that lampholder when I get a new one but is it
possible that has been the cause of the fault...is it possible the
bulb was sitting with only one of the contacts "making contact" .Could
that cause the CB to trip? I was removing some stuff out the cupboard
so may have knocked it on my way out...

The quick easy way to fault find - is to turn everything off, see if it
will then reset, followed by turning things back on again one at a time
until it trips.

The lamp contacts not making contact would not cause the tripping, but
a faulty lamp holder could, a faulty lamp, or a fault (short) on the
flex.

--
Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk

On Aug 14, 5:14*pm, Harry Bloomfield
wrote:
Usenet Nutter expressed precisely :

I am going to change that lampholder when I get a new one but is it
possible that has been the cause of the fault...is it possible the
bulb was sitting with only one of the contacts "making contact" .Could
that cause the CB to trip? *I was removing some stuff out the cupboard
so may have knocked it on my way out...

The quick easy way to fault find - is to turn everything off, see if it
will then reset, followed by turning things back on again one at a time
until it trips.

The lamp contacts not making contact would not cause the tripping, but
a faulty lamp holder could, a faulty lamp, or a fault (short) on the
flex.

Until fixed its an immediate fire risk. The mcb tripped because excess
short current flowed, now hopefully none is flowing. When somewhere
between the 2 flows, the result is fire.


NT