Fault finding lights stopped working

[cragglecat]

Hi all, I switched off the downstairs light circuit at the consumer unit, switched back on and now none of the lights on the circuit are working. I've put a new bulb in one light just to check they hadn't all blown for some reason - no joy. Any advice on what usually causes this issue?

Thanks,

Craig.

P.s. The only other thing I've done recently is fit a new ceiling light in my lounge which is on a different circuit so I'm assuming this is not related? Living room lights are still working fine.

 

[deadshort]

Hi, some mcb's need the breaker to be pushed down to the bottom and then back up to reset them. It's not unheard of for breakers to become faulty.

Regards,

DS

 

[ban-all-sheds]

Hi all, I switched off the downstairs light circuit at the consumer unit.

Why?

 

[cragglecat]

Why?

I was going to change a ceiling light at the weekend and was checking which switch would isolate the lights.

 

[cragglecat]

Hi, some mcb's need the breaker to be pushed down to the bottom and then back up to reset them. It's not unheard of for breakers to become faulty

Thanks but wouldn't this then affect all sockets and lights rather than just the one circuit I switched on and off? I have power everywhere else in the house.

 

[PrenticeBoyofDerry]

If all the lights are off on this circuit and no other circuit is off, I would first check at the consumer unit, that this lighting circuit is not protected by a separate RCD that is not covering other circuits and that is in the on position.
Then it would be a case of looking for loose connections.
It could be a loose live or neutral, this could be right at the start of the circuit either at MCB/RCBO or neutral busbar. Also check that when the MCB/RCBO is on that a voltage is being detected at the live terminal of the device, you will be looking for a voltage of something near 240V plus/minus 10%. Use a two pole approved voltage indicator for this test.
If no voltage when device is closed, then you have a contact failure at the device, so check the device is fitted correctly to the live busbar (isolation at the main ISO required and proved) if it is, then check a voltage appears at the live busbar when main ISO and any associated RCD are closed, If voltage is present of about 240V, then the device needs replacing.If no voltage check busbar connection to ISO.(again isolation required and proved)
The next stage would be to check at the first light fitting/junction/switch after the consumer unit for live voltage an loose connections.
Depending on the configuration of your installation, it could be that the first part of the loop could be either at a fitting, switch or junction box, so investigation would be required. Also check that lamps (bulbs) are in working condition. As you could have a blown lamp/bulb at the first fitting and the loose connection then be at the second fitting.
So investigation is needed and a means of testing safely.
Ideally I would recommend extensive testing if required are performed with the circuit dead, and continuity tests performed.

 

[JohnW2]

Hi, some mcb's need the breaker to be pushed down to the bottom and then back up to reset them. It's not unheard of for breakers to become faulty

Thanks but wouldn't this then affect all sockets and lights rather than just the one circuit I switched on and off? I have power everywhere else in the house.

Assuming we're just talking about the breaker (MCB or RCBO) for the lighting circuit, then it will affect only that one circuit. You aren't talking about an RCD which covers multiple circuits, are you?

Kind Regards, John