"David WE Roberts" wrote in message
...

"David WE Roberts" wrote in message
...
Just set off to do my good deed of the day.
Replacing the PIR outside light by the front door which had given up the
ghost.
New light half price from Homebase was the incentive :-)

snip
My conclusion is that somehow in moving the wires around I have induced a
short between live, neutral and earth somewhere in the power wire which
disappears into the cavity wall to gawd knows where.
Have I missed anything which might be good news?
snip

I was double checking that the central heating was off the lighting
circuit by taking the CB up half way (this gives power - full up trips)
whilst someone watched the programmer for signs of life.

I had just used this trick to locate any lights still turned on and turn
them off.
To my surprise, after I heard the boiler fire up the breaker stayed set.

So I am now wondering if the CH was just putting too much load on the CB
when first reset - the initial suge knocking it over again.

So the thing I do need to confirm - in a power cable from a lighting
circuit where some lights may be turned on should I see an open circuit
between live and neutral?
Doesn't seem right to me.
Seems more likely that a small contact has burned itself out during the
repeated short power ups.

I am now not going to touch anything until it is daylight and the house is
toasty warm.

Then presumably I play hunt the phantom fault.


After a good night's sleep in a warm house I have had further thoughts.
I think I have had a phantom problem and gone too far seeking a solution.

Firstly, I think that the main issue was that the CH was trying to fire up
when I reset the breaker, and the initial surge was too much for the breaker
to cope with. After a few tries and holding the switch half way the breaker
reset O.K. and has been fine overnight. [JR suggested the problem might be
in the breaker.]

Secondly, in looking for a fault (which may not have been there) I was
trying too hard.
If there is a switch closed anywhere in the circuit (CH, a light, whatever)
then there is a route for the current to pass between live and neutral.
So a tester will show a connection between L&N.
So this isn't a fault, but expected behaviour.
I think.....

Now hoping that a sensitive breaker is the explanation for everything.

Thanks for all the suggestions.

Dave R

--
No plan survives contact with the enemy.
[Not even bunny]

Helmuth von Moltke the Elder

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