another question (doing up an old house and lots of questions I'm
afraid...!! )

We just got our house rewired.

The electricians put in a new circuit breaker (??) in the cellar where
the electricity comes in. It comprises about sixteen switches (all
used). They have placed the cellar and the 1st floor lights on the same
switch (all are used).

Since they have fitted this, 2 bulbs have gone on the `1st floor. Each
time, the switch in the basement has tripped and lights have gone in
the cellar and the 1st floor. Bit of a pain in the butt since we need a
torch to go down to the cellar to switch it, but is this normal
behaviour? Should I worry about any of the electricians' wiring?

thanks for any replies

In article .com,
writes:
another question (doing up an old house and lots of questions I'm
afraid...!! )

We just got our house rewired.

The electricians put in a new circuit breaker (??) in the cellar where
the electricity comes in. It comprises about sixteen switches (all
used). They have placed the cellar and the 1st floor lights on the same
switch (all are used).

Since they have fitted this, 2 bulbs have gone on the `1st floor. Each
time, the switch in the basement has tripped and lights have gone in
the cellar and the 1st floor. Bit of a pain in the butt since we need a
torch to go down to the cellar to switch it, but is this normal
behaviour? Should I worry about any of the electricians' wiring?

It can happen with MCB's.
You could ask the electricians to change the lighting circuits
for 5A BS1361 cartridge fuses, which will stop this in most
cases. In some cases, changing the MCB from a Type B to a Type C
might help, but in other cases it doesn't.

Alternatively, change over to low energy lamps, which don't
cause this.

--
Andrew Gabriel

Andrew Gabriel wrote:

It can happen with MCB's.
You could ask the electricians to change the lighting circuits
for 5A BS1361 cartridge fuses, which will stop this in most
cases. In some cases, changing the MCB from a Type B to a Type C
might help, but in other cases it doesn't.

Alternatively, change over to low energy lamps, which don't
cause this.

The other easy thing to do is to have a battery maintained emergency
light (about £30) installed near the consumer unit, and have it powered
from the same circuit that feeds the lights in the room the CU is in.

That way when you do loose the circuit the light comes on and you can
see to reset it.

--
Cheers,

John.

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

Andrew Gabriel wrote:
In article .com,
writes:

another question (doing up an old house and lots of questions I'm
afraid...!! )

We just got our house rewired.

The electricians put in a new circuit breaker (??) in the cellar where
the electricity comes in. It comprises about sixteen switches (all
used). They have placed the cellar and the 1st floor lights on the same
switch (all are used).

Since they have fitted this, 2 bulbs have gone on the `1st floor. Each
time, the switch in the basement has tripped and lights have gone in
the cellar and the 1st floor. Bit of a pain in the butt since we need a
torch to go down to the cellar to switch it, but is this normal
behaviour? Should I worry about any of the electricians' wiring?


It can happen with MCB's.
You could ask the electricians to change the lighting circuits
for 5A BS1361 cartridge fuses, which will stop this in most
cases. In some cases, changing the MCB from a Type B to a Type C
might help, but in other cases it doesn't.

Alternatively, change over to low energy lamps, which don't
cause this.

Tried 'C' type MCBs - doesn't seem to make much difference

Malcolm

wrote:
another question (doing up an old house and lots of questions I'm
afraid...!! )

We just got our house rewired.

The electricians put in a new circuit breaker (??) in the cellar where
the electricity comes in. It comprises about sixteen switches (all
used). They have placed the cellar and the 1st floor lights on the same
switch (all are used).

Since they have fitted this, 2 bulbs have gone on the `1st floor. Each
time, the switch in the basement has tripped and lights have gone in
the cellar and the 1st floor. Bit of a pain in the butt since we need a
torch to go down to the cellar to switch it, but is this normal
behaviour? Should I worry about any of the electricians' wiring?

thanks for any replies

Sadly it is fairly normal - here anyway.

Candle bulbs are the worst offenders.

The Natural Philosopher wrote:
wrote:
another question (doing up an old house and lots of questions I'm
afraid...!! )

We just got our house rewired.

The electricians put in a new circuit breaker (??) in the cellar where
the electricity comes in. It comprises about sixteen switches (all
used). They have placed the cellar and the 1st floor lights on the same
switch (all are used).

Since they have fitted this, 2 bulbs have gone on the `1st floor. Each
time, the switch in the basement has tripped and lights have gone in
the cellar and the 1st floor. Bit of a pain in the butt since we need a
torch to go down to the cellar to switch it, but is this normal
behaviour? Should I worry about any of the electricians' wiring?

I noticed this when I replaced our CU. I believe the reason it happens
is that as a bulb blows, there is a split second when the filament
breaks, and an arc appears across it. IIRC, the resistance of an arc is
very low (milliohms ?) which causes the current drawn to appear almost
infinite - certainly greater than the 16A of the MCB - hence the trip.
This doesn't happen with fuses because the duration of the arc is so
short that a normal fuse can't react in time. However the MCB can react
much quicker.

I vaguely recall (maybe from uk.d-i-y, a google might help) that there
are "slow blow" MCBs for just this purpose, BICBW

The Natural Philosopher typed


wrote:
another question (doing up an old house and lots of questions I'm
afraid...!! )

We just got our house rewired.

The electricians put in a new circuit breaker (??) in the cellar where
the electricity comes in. It comprises about sixteen switches (all
used). They have placed the cellar and the 1st floor lights on the same
switch (all are used).

Since they have fitted this, 2 bulbs have gone on the `1st floor. Each
time, the switch in the basement has tripped and lights have gone in
the cellar and the 1st floor. Bit of a pain in the butt since we need a
torch to go down to the cellar to switch it, but is this normal
behaviour? Should I worry about any of the electricians' wiring?

thanks for any replies

Sadly it is fairly normal - here anyway.

Candle bulbs are the worst offenders.

The mini-globes in my hall do it a lot too.

--
Helen D. Vecht:
Edgware.

Helen Deborah Vecht wrote:
The Natural Philosopher typed


wrote:
another question (doing up an old house and lots of questions I'm
afraid...!! )

We just got our house rewired.

The electricians put in a new circuit breaker (??) in the cellar where
the electricity comes in. It comprises about sixteen switches (all
used). They have placed the cellar and the 1st floor lights on the same
switch (all are used).

Since they have fitted this, 2 bulbs have gone on the `1st floor. Each
time, the switch in the basement has tripped and lights have gone in
the cellar and the 1st floor. Bit of a pain in the butt since we need a
torch to go down to the cellar to switch it, but is this normal
behaviour? Should I worry about any of the electricians' wiring?

thanks for any replies

Sadly it is fairly normal - here anyway.

Candle bulbs are the worst offenders.

The mini-globes in my hall do it a lot too.

Yus, I had one of those do mine in again as well.

wrote:
another question (doing up an old house and lots of questions I'm
afraid...!! )

We just got our house rewired.

The electricians put in a new circuit breaker (??) in the cellar where
the electricity comes in. It comprises about sixteen switches (all
used). They have placed the cellar and the 1st floor lights on the same
switch (all are used).

As others have said...

However, if you use energy saving lights, they don't usually do this.

The message .com
from contains these words:

Since they have fitted this, 2 bulbs have gone on the `1st floor. Each
time, the switch in the basement has tripped and lights have gone in
the cellar and the 1st floor.

Happens all the time. As the filament breaks it causes an arc inside the
bulb, which spreads along the remains of the filament to the wires that
carry the current up to it. Arcs have very low resistances - far lower
than a working bulb and the surge in current pops the circuit breaker.
Most bulbs now have an internal fuse - but it still happens.

--
Skipweasel
Pay no attention to that man behind the curtain.