Can anyone give me any tips on how to locate a short in my house lighting
circuit?

I was sitting here at my desk and the whole upstairs lighting went out. The
circuit breaker had flipped. When I tried to un-flip it, I saw a spark and
it wouldn't flip back, so I conclude the short is still present.

No alterations have been made to the wiring for several weeks here, so I
can't imagine what might have happened. I don't have rats in the loft.

I have a mains testing screwdriver at hand (and a multi-meter if needed).

Thank you!

Al

On 14/03/2012 19:47, AL_n wrote:
Can anyone give me any tips on how to locate a short in my house lighting
circuit?

I was sitting here at my desk and the whole upstairs lighting went out. The
circuit breaker had flipped. When I tried to un-flip it, I saw a spark and
it wouldn't flip back, so I conclude the short is still present.

No alterations have been made to the wiring for several weeks here, so I
can't imagine what might have happened. I don't have rats in the loft.

I have a mains testing screwdriver at hand (and a multi-meter if needed).

Are all the lights switched off? Yes, I know it's trickier to tell if
there's no power, but if you do manage to switch one off and have the
power come on, you've got a really good clue where the problem is.

Then start at the bulbs - remove, does everything else start working?

IME you don't need to do much more to find the problem. It'll probably
be a bulb or switch. Of course having said this you'll now be the one
with the short hidden in the plaster.

(is that a neon screwdriver? :-) Regardless of the comments flying
around this NG (which are probably worth reading), it won't help you,
because you can't turn the power on yet)

AL_n wrote:

I was sitting here at my desk and the whole upstairs lighting went out. The
circuit breaker had flipped. When I tried to un-flip it, I saw a spark and
it wouldn't flip back, so I conclude the short is still present.

MCB or RCD?

No alterations have been made to the wiring for several weeks here, so I
can't imagine what might have happened. I don't have rats in the loft.

Try turning all lights off (or reversing them if they're 2-way or 3-way)
and resetting the breaker, turn lights back one-by-one until it trips
again, might narrow it down, unless the problem is isn't in a switched
part of the circuit.

On 14/03/2012 19:54, Clive George wrote:
On 14/03/2012 19:47, AL_n wrote:
Can anyone give me any tips on how to locate a short in my house lighting
circuit?

I was sitting here at my desk and the whole upstairs lighting went
out. The
circuit breaker had flipped. When I tried to un-flip it, I saw a spark
and
it wouldn't flip back, so I conclude the short is still present.

No alterations have been made to the wiring for several weeks here, so I
can't imagine what might have happened. I don't have rats in the loft.

I have a mains testing screwdriver at hand (and a multi-meter if needed).

Are all the lights switched off? Yes, I know it's trickier to tell if
there's no power, but if you do manage to switch one off and have the
power come on, you've got a really good clue where the problem is.

Then start at the bulbs - remove, does everything else start working?

IME you don't need to do much more to find the problem. It'll probably
be a bulb or switch. Of course having said this you'll now be the one
with the short hidden in the plaster.

(is that a neon screwdriver? :-) Regardless of the comments flying
around this NG (which are probably worth reading), it won't help you,
because you can't turn the power on yet)

I was about to say he could turn screws with it, but then again they are
often too small to do that well ;-)

--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

On 14/03/2012 19:47, AL_n wrote:
Can anyone give me any tips on how to locate a short in my house lighting
circuit?

I was sitting here at my desk and the whole upstairs lighting went out. The
circuit breaker had flipped. When I tried to un-flip it, I saw a spark and
it wouldn't flip back, so I conclude the short is still present.

No alterations have been made to the wiring for several weeks here, so I
can't imagine what might have happened. I don't have rats in the loft.


Given the circumstance, a lamp failed short would seem most likely. Turn
off / remove bulbs to try to find it.


--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

Andy Burns wrote in
o.uk:

AL_n wrote:

I was sitting here at my desk and the whole upstairs lighting went
out. The circuit breaker had flipped. When I tried to un-flip it, I
saw a spark and it wouldn't flip back, so I conclude the short is
still present.

MCB or RCD?

No alterations have been made to the wiring for several weeks here,
so I can't imagine what might have happened. I don't have rats in the
loft.

Try turning all lights off (or reversing them if they're 2-way or
3-way) and resetting the breaker, turn lights back one-by-one until it
trips again, might narrow it down, unless the problem is isn't in a
switched part of the circuit.


Thanks to you all, for the helpful suggestions. This is strange: I switched
all the lighs off and then flipped the circuit breaker. It flipped back to
the "on" position.

I then turned all the lights on, one by one, expecting one of them to cause
the short again. None of them did! Now all the lights are working.

What does this mean? It makes no sense to me!

Al

On Mar 14, 8:38*pm, "AL_n" wrote:
Andy Burns wrote innews:99SdnRqB0YRSav3SnZ2dnUVZ8gOdnZ2d@brightview .co.uk:



AL_n wrote:

I was sitting here at my desk and the whole upstairs lighting went
out. The circuit breaker had flipped. When I tried to un-flip it, I
saw a spark and it wouldn't flip back, so I conclude the short is
still present.

MCB or RCD?

No alterations have been made to the wiring for several weeks here,
so I can't imagine what might have happened. I don't have rats in the
loft.

Try turning all lights off (or reversing them if they're 2-way or
3-way) and resetting the breaker, turn lights back one-by-one until it
trips again, might narrow it down, unless the problem is isn't in a
switched part of the circuit.

Thanks to you all, for the helpful suggestions. This is strange: I switched
all the lighs off and then flipped the circuit breaker. It flipped back to
the "on" position.

I then turned all the lights on, one by one, expecting one of them to cause
the short again. None of them did! Now all the lights are working.

What does this mean? It makes no sense to me!

Al

sometimes filament lamps arc over when they fail, causing a very large
current surge.

http://wiki.diyfaq.org.uk/index.php?...on_screwdriver


NT

On Mar 14, 8:38*pm, "AL_n" wrote:
Andy Burns wrote innews:99SdnRqB0YRSav3SnZ2dnUVZ8gOdnZ2d@brightview .co.uk:





AL_n wrote:

I was sitting here at my desk and the whole upstairs lighting went
out. The circuit breaker had flipped. When I tried to un-flip it, I
saw a spark and it wouldn't flip back, so I conclude the short is
still present.

MCB or RCD?

No alterations have been made to the wiring for several weeks here,
so I can't imagine what might have happened. I don't have rats in the
loft.

Try turning all lights off (or reversing them if they're 2-way or
3-way) and resetting the breaker, turn lights back one-by-one until it
trips again, might narrow it down, unless the problem is isn't in a
switched part of the circuit.

Thanks to you all, for the helpful suggestions. This is strange: I switched
all the lighs off and then flipped the circuit breaker. It flipped back to
the "on" position.

I then turned all the lights on, one by one, expecting one of them to cause
the short again. None of them did! Now all the lights are working.

What does this mean? It makes no sense to me!

Al- Hide quoted text -

- Show quoted text -

Other possibilities:-

Any _down_stairs lights sneakily placed on the _up_stairs circuit?
Lights in cupboards you didn't think of?

A cable run in an unprotected/shallow notch in a joist too close to a
loose floorboard/nail. Thermal expansion/contraction might start/stop
the short. Your mention of "No alterations have been made to the
wiring for several weeks" implies there have been some relatively
recently, or the floorboards disturbed for some other reason. and this
kind of fault can take time to show, when someone walks over the
offending point.

Similarly, have you moved anything in the loft recently? Try waggling
any cables up there.

Loose screws in ceiling roses can cause arcing and hence carbon
tracks, but don't usually self-heal.

Chris

On Wed, 14 Mar 2012 20:24:33 +0000, John Rumm
wrote:

On 14/03/2012 19:54, Clive George wrote:
On 14/03/2012 19:47, AL_n wrote:
Can anyone give me any tips on how to locate a short in my house lighting
circuit?

I was sitting here at my desk and the whole upstairs lighting went
out. The
circuit breaker had flipped. When I tried to un-flip it, I saw a spark
and
it wouldn't flip back, so I conclude the short is still present.

No alterations have been made to the wiring for several weeks here, so I
can't imagine what might have happened. I don't have rats in the loft.

I have a mains testing screwdriver at hand (and a multi-meter if needed).

Are all the lights switched off? Yes, I know it's trickier to tell if
there's no power, but if you do manage to switch one off and have the
power come on, you've got a really good clue where the problem is.

Then start at the bulbs - remove, does everything else start working?

IME you don't need to do much more to find the problem. It'll probably
be a bulb or switch. Of course having said this you'll now be the one
with the short hidden in the plaster.

(is that a neon screwdriver? :-) Regardless of the comments flying
around this NG (which are probably worth reading), it won't help you,
because you can't turn the power on yet)

I was about to say he could turn screws with it, but then again they are
often too small to do that well ;-)

They are great at unscrewing things, screwing them up again usually
results in the red cap unscrewing itself and releasing the
ping****its.

--
Graham.
%Profound_observation%

NT wrote in news:11eef274-6467-42dd-8475-
:

sometimes filament lamps arc over when they fail, causing a very large
current surge.

I only have one incandescent bulb on the affected floor. It is a 150W bulb.
However, it has not blown. All the other bulbs are fluorescent or LED.

Al

AL_n wrote:
Andy Burns wrote in
o.uk:

AL_n wrote:

I was sitting here at my desk and the whole upstairs lighting went
out. The circuit breaker had flipped. When I tried to un-flip it,
I saw a spark and it wouldn't flip back, so I conclude the short
is still present.

MCB or RCD?

No alterations have been made to the wiring for several weeks
here, so I can't imagine what might have happened. I don't have
rats in the loft.

Try turning all lights off (or reversing them if they're 2-way or
3-way) and resetting the breaker, turn lights back one-by-one until
it trips again, might narrow it down, unless the problem is isn't
in a switched part of the circuit.


Thanks to you all, for the helpful suggestions. This is strange: I
switched all the lighs off and then flipped the circuit breaker. It
flipped back to the "on" position.

I then turned all the lights on, one by one, expecting one of them to
cause the short again. None of them did! Now all the lights are
working.

What does this mean? It makes no sense to me!


How long is a piece of string?

Maybe the MCB is "tired" and will not switch on when under load? It is not
uncommon.

--
Adam

On Mar 14, 9:06*pm, "AL_n" wrote:
NT wrote in news:11eef274-6467-42dd-8475-
:

sometimes filament lamps arc over when they fail, causing a very large
current surge.

I only have one incandescent bulb on the affected floor. It is a 150W bulb.
However, it has not blown. All the other bulbs are fluorescent or LED.


Well the thing is that if one is no longer working, it is likely the
cause of the fault soyou can chuck it out. Problem solved.

"ARWadsworth" wrote in
:

Maybe the MCB is "tired" and will not switch on when under load? It is
not uncommon.



That seems like a plausible explanation. I wasn't aware of that phenomenon.

Hopefully all will be well from now on! BTW, my circuit breakers are
plugged into an old-style fuse box. It's not one of the more recent
consumer units that flips their MCB's every time someone breathes too
heavily.

Al

AL_n wrote:
"ARWadsworth" wrote in
:

Maybe the MCB is "tired" and will not switch on when under load? It
is not uncommon.



That seems like a plausible explanation. I wasn't aware of that
phenomenon.

Hopefully all will be well from now on! BTW, my circuit breakers are
plugged into an old-style fuse box.




It's not one of the more recent
consumer units that flips their MCB's every time someone breathes too
heavily.

IMHO the type of MCBs you have (plug in Wlylex fuse replacements?) are the
sort of MCBs that often fail to turn on when under load.


--
Adam

On Mar 14, 9:36*pm, "AL_n" wrote:
"ARWadsworth" wrote :

Maybe the MCB is "tired" and will not switch on when under load? It is
not uncommon.

That seems like a plausible explanation. I wasn't aware of that phenomenon.

AL_n wrote
Andy Burns wrote
AL_n wrote

I was sitting here at my desk and the whole upstairs lighting went
out. The circuit breaker had flipped. When I tried to un-flip it, I
saw a spark and it wouldn't flip back, so I conclude the short is
still present.

MCB or RCD?

No alterations have been made to the wiring for several weeks here,
so I can't imagine what might have happened. I don't have rats in the loft.

Try turning all lights off (or reversing them if they're 2-way or
3-way) and resetting the breaker, turn lights back one-by-one until
it trips again, might narrow it down, unless the problem is isn't in
a switched part of the circuit.

Thanks to you all, for the helpful suggestions. This is strange:
Is witched all the lighs off and then flipped the circuit breaker.
It flipped back to the "on" position.

I then turned all the lights on, one by one, expecting one of them to
cause the short again. None of them did! Now all the lights are working.

What does this mean? It makes no sense to me!

That you have a partial short somewhere in the system.

Most likely in what you changed in the changes you made several weeks ago.

Or its an intermittent fault somewhere, but thats not all
that likely unless you have got a water leak somewhere.

AL_n wrote
NT wrote

sometimes filament lamps arc over when
they fail, causing a very large current surge.

I only have one incandescent bulb on the affected floor. It is a 150W
bulb. However, it has not blown. All the other bulbs are fluorescent or LED.

You dont usually get intermittent faults in those that blow the breaker.

Its much more likely to be in what you did several weeks ago.

Corse it can be a coincidence too.

Could be a water leak.

Something only shorts when it gets hot?
Brian

--
Brian Gaff....Note, this account does not accept Bcc: email.
graphics are great, but the blind can't hear them
Email:
__________________________________________________ __________________________________________________ __________


"AL_n" wrote in message
...
Andy Burns wrote in
o.uk:

AL_n wrote:

I was sitting here at my desk and the whole upstairs lighting went
out. The circuit breaker had flipped. When I tried to un-flip it, I
saw a spark and it wouldn't flip back, so I conclude the short is
still present.

MCB or RCD?

No alterations have been made to the wiring for several weeks here,
so I can't imagine what might have happened. I don't have rats in the
loft.

Try turning all lights off (or reversing them if they're 2-way or
3-way) and resetting the breaker, turn lights back one-by-one until it
trips again, might narrow it down, unless the problem is isn't in a
switched part of the circuit.


Thanks to you all, for the helpful suggestions. This is strange: I
switched
all the lighs off and then flipped the circuit breaker. It flipped back to
the "on" position.

I then turned all the lights on, one by one, expecting one of them to
cause
the short again. None of them did! Now all the lights are working.

What does this mean? It makes no sense to me!

Al

But he said they all work, and in any case normally this failure tends to
vaporise the shorted area and the bulb is then just open circuit. I suspect
something getting hot or failing intermittently. It could be a leaky
capacitor that eventually breaks down but recovers enough to allow the
reconnection. Some older Thorne fittings seemed to have an annoying
tendency to do this sort of thing.
Brian

--
Brian Gaff....Note, this account does not accept Bcc: email.
graphics are great, but the blind can't hear them
Email:
__________________________________________________ __________________________________________________ __________


"NT" wrote in message
...
On Mar 14, 8:38 pm, "AL_n" wrote:
Andy Burns wrote
innews:99SdnRqB0YRSav3SnZ2dnUVZ8gOdnZ2d@brightview .co.uk:



AL_n wrote:

I was sitting here at my desk and the whole upstairs lighting went
out. The circuit breaker had flipped. When I tried to un-flip it, I
saw a spark and it wouldn't flip back, so I conclude the short is
still present.

MCB or RCD?

No alterations have been made to the wiring for several weeks here,
so I can't imagine what might have happened. I don't have rats in the
loft.

Try turning all lights off (or reversing them if they're 2-way or
3-way) and resetting the breaker, turn lights back one-by-one until it
trips again, might narrow it down, unless the problem is isn't in a
switched part of the circuit.

Thanks to you all, for the helpful suggestions. This is strange: I
switched
all the lighs off and then flipped the circuit breaker. It flipped back to
the "on" position.

I then turned all the lights on, one by one, expecting one of them to
cause
the short again. None of them did! Now all the lights are working.

What does this mean? It makes no sense to me!

Al

sometimes filament lamps arc over when they fail, causing a very large
current surge.

http://wiki.diyfaq.org.uk/index.php?...on_screwdriver


NT

Might be worth turning all off and watching if the meter runs faster when
you connect the circuit, and then doing the same with each individual light
and see if the current increases. Ideally you would need some kind of clamp
meter to be sure what is going on if you suspect one fitting or part of the
wiring. Its a real pain when things are not constant.
Brian

--
Brian Gaff....Note, this account does not accept Bcc: email.
graphics are great, but the blind can't hear them
Email:
__________________________________________________ __________________________________________________ __________


"AL_n" wrote in message
...
"ARWadsworth" wrote in
:

Maybe the MCB is "tired" and will not switch on when under load? It is
not uncommon.



That seems like a plausible explanation. I wasn't aware of that
phenomenon.

Hopefully all will be well from now on! BTW, my circuit breakers are
plugged into an old-style fuse box. It's not one of the more recent
consumer units that flips their MCB's every time someone breathes too
heavily.

Al