tripped MCB

This morning (prior to fitting a replacement lightswitch), whils

polyfilling a small section of a wall - I forgot to switch off th electrics and managed to have the live wire touch the earth wire

The MCB tripped for the downstairs light circuit (as it should) bu after resetting the MCB - it reset easily - I have lost all the light downstairs - there is no current going through at all. All the othe circuits are fine in the house.

What could the matter be? Can anyone help please?

Thank

-- eastangliacyclist

Reply to
eastangliacyclist
Loading thread data ...

something somewhere burnt out due to the current surge. Lightswitches are vulnerable to this.

NT

Reply to
meow2222

Lightswitches

Or maybe the MCB died electrically despite apparently resetting?

AWEM

Reply to
Andrew Mawson

Is the light switch you were working on likely to be the first light on the circuit? If it is not then that makes it less likely (although not impossible) that it is a wiring related failure.

It is possible that the MCB has failed. To be certain you would need to take the cover off the CU and test the output terminal with a volt meter to make sure it is electrically "on" when it ought to be.

Reply to
John Rumm

Best use a multimeter to find the fault.

NT

Reply to
meow2222

Hi, Thanks for all the advice.

The lightswitch is right at the end of the house - in the utility roo

- so not at the start of the circuit. I have also swapped the MCB wit a different one (in case it was damaged) and still no current.

I guess that something has burnt out somewhere - I'll keep you informe of progress.

Thanks EA

-- eastangliacyclist

Reply to
eastangliacyclist

If you are sure you have tried all the lights on that circuit and none of them work, then try and identify the first light on the circuit. Check to see if power is reaching its ceiling rose. There is a reasonable chance that will be where your problem is.

Reply to
John Rumm

Now John, you KNOW the broken wire is ALWAYS in the least accessable position !

AWEM

Reply to
Andrew Mawson

On Mon, 19 Mar 2007 11:22:35 +0000 someone who may be eastangliacyclist wrote this:-

How do you know?

How do you know? Have you measured the voltage?

Reply to
David Hansen

and the last place you look....

(then again, to carry on looking once you had found it would suggest a "special" type of intelligence! ;-)

Reply to
John Rumm

In message , snipped-for-privacy@care2.com writes

Best use a properly designed set of testlamps to find the fault. Domestic multimeters in the wrong hands can become bombs when they are inadvertently applied to mains voltage while the leads are in the 10A sockets.

That's why many meters now don't have a 10A AC setting. (I think it's a liability thing.)

Industrial test meters have a good quality HRC fuse in series with the

10A range to break the circuit in a controlled manner.
Reply to
Clive Mitchell

6A mcb not good enough?

There are other risks too, such as touching one prod while poking the other... one needs some competence when dealing with situations with inherent risks. And ideally the meter would be cat whichever it is etc.

NT

Reply to
meow2222

In message , snipped-for-privacy@care2.com writes

Not if you poke the meter on the supply side.

The REALLY nasty accidents with cheap meters happen on industrial supplies.

Reply to
Clive Mitchell

formatting link
and suggest if you want to prod round a consumer unit then you do need a good safe DVM such as some of the modern Flukes or the Meterman range.

NB there is a cheap DVM that is on sale at some DIY stores, this has a 10A range that on the sample that I recived was proctected by a glass 10A fuse....

Reply to
James Salisbury

In message , James Salisbury writes

Which is as good as no protection, since the glass fuses arc internally through the metal vapour from the exploded fuse, failing to break the circuit in a controlled manner and adding to the final explosion.

Like this one....

formatting link

Reply to
Clive Mitchell

Is it just me who doesn't like actually holding a dmm when measuring mains or higher voltages? Since it has a stand anyway, I usually put it down on a surface or hang it when using it. It does have a 20A Bussmann HRC fuse, (and a 5A for the lower ranges) but I would still not want to be holding it if I'd inadvertently stuck the probes in the "Amp" sockets while checking mains voltage ;) :)

Lee

Reply to
Lee

HomeOwnersHub website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.