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question for electricians

njdbaxter

Prominent Member
one ceiling light in the house is playing up. Its a standard ceiling rose with the light bulb fitting.

when I press the switch it either will come on for as short while, or just flicker on then straight off, or nothing will happen. Happened since yesterday afternoon. Changing the bulb does nothing.

all other lights on same circuit breaker are fine and the light doesn't trip the circuit breaker.

so would I be right in guessing that there may be a lose connection in the ceiling rose connection or the switch.
 

RBZ5416

Distinguished Member
I'm no electrician but that sounds the most likely. If it's a pendant it could also be a bad connection in the bulb holder. They're dirt cheap if you want to replace the whole thing.

Just make sure the mains is off before you start to play & make a careful note of or photograph the wiring before disconnecting anything. Check Kieron's thread for what happens if you don't!
 
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blue max

Distinguished Member
Not an electrician, so usual warnings about how it can kill, but...

Turn off circuit at fuseboard (check!). You really need a circuit tester - even a basic light up job will do to be absolutely sure (couple of quid if you don't have one).

Unscrew carefully the rose at the ceiling. Before you do anything else, take a pic of it or draw the wiring. You may need a torch.

They check all connections are sound. Hopefully you will spot one that isn't. Or the lamp holder is defective.

Good luck.

Oops beaten by the croc : )
 

Wahreo

Distinguished Member
Best way to tell if it's the switch is to undo the switch, pop a tester on the red or brown live cable to see if it's live. then move the tester to the black or blue cable to see if that goes live when you flick the switch on. If it doesn't go live then your switch is kaput.
 

njdbaxter

Prominent Member
Not an electrician, so usual warnings about how it can kill, but...

Turn off circuit at fuseboard (check!). You really need a circuit tester - even a basic light up job will do to be absolutely sure (couple of quid if you don't have one).

Unscrew carefully the rose at the ceiling. Before you do anything else, take a pic of it or draw the wiring. You may need a torch.

They check all connections are sound. Hopefully you will spot one that isn't. Or the lamp holder is defective.

Good luck.



Oops beaten by the croc : )

have a circuit tester in the house, like this one

not sure how to use it
 

blue max

Distinguished Member
With suspected bad connections it's easier to just check everything's tight first. In that case all you need is a screwdriver.

I meant so he could physically check it wasn't live before fiddling with it!

That looks very elaborate and I can't help. I was just referring to one of the 'screwdriver' types with a light inside.

Just as a precaution.
 

Wahreo

Distinguished Member
I must admit, I use my neon tester all the time when I possibly shouldn't. I do have a Multimeter though, which I bought from Lidl which I have used to install dozens of Underfloor heating systems over the years. Well worth the money.
 
blue max said:
I meant so he could physically check it wasn't live before fiddling with it!

That looks very elaborate and I can't help. I was just referring to one of the 'screwdriver' types with a light inside.

Just as a precaution.

No, no and thrice no. Neon screwdrivers, volt sticks etc do not prove isolation and are likely to get you killed. GET AND ELECTRICIAN IN.
 

Sonic67

Banned
I wouldn't bother with a neon screwdriver for testing electricity. I use a steinel combi check.
 

paulyoung666

Distinguished Member
I wouldn't bother with a neon screwdriver for testing electricity. I use a steniel combi check.

As above get an electrician in , we got issued neon screwdrivers in our kit at work , they come in quite handy as they have a pocket clip on them , we have found they are perfect for poking air solenoids :D
 

blue max

Distinguished Member
No, no and thrice no. Neon screwdrivers, volt sticks etc do not prove isolation and are likely to get you killed. GET AND ELECTRICIAN IN.

Not questioning you personally, but have always used one to double check AFTER I am satisfied the power is off. I just touch every wire to confirm myself it is dead. I've wired all my sockets, and all my lighting this way and am obviously still here.

I've been using one for years. What is the risk that you think I was facing by using a neon tester particularly?
 

Sonic67

Banned
The thing stopping you getting a shock in those neon testers is a little resistor or something. I worry one day it will fail. I use to work on a UN camp that was a factory before the conflict started. An electrician called Mirv who had worked there used to test everything with one of those screwdrivers. One day an overhead electrical cable came down off a pylon. Not the huge pylons but still probably maybe 415v or something. They got me and I said I wasn't going near it and to keep everyone away from it. On the other side of this crowd watching the cable Mirv appeared, walked up, stuck this screwdriver on it and then said, "is good." I had visions of him turning into something like off a cartoon.
 
blue max said:
Not questioning you personally, but have always used one to double check AFTER I am satisfied the power is off. I just touch every wire to confirm myself it is dead. I've wired all my sockets, and all my lighting this way and am obviously still here.

I've been using one for years. What is the risk that you think I was facing by using a neon tester particularly?

Neons should be used as an indication tool, not a proving one. I'm glad you've not killed yourself, but they are not foolproof and shouldn't be treated as such.

Out of interest, do you know the max Zs on all the circuits you have wired and are you comfortable that you would get instantaneous disconnection for ADS?

And to answer your question, a neon is unreliable. Easy to short and explode in your face and dangerous as there's no finger guards for the careless or tired. Get a Fluke 120 for about 40 notes and treat yourself and stay safer :)

Further edit, they need an earth path to work....guess what that includes?
 
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blue max

Distinguished Member
Neons should be used as an indication tool, not a proving one. I'm glad you've not killed yourself, but they are not foolproof and shouldn't be treated as such.

Out of interest, do you know the max Zs on all the circuits you have wired and are you comfortable that you would get instantaneous disconnection for ADS?

And to answer your question, a neon is unreliable. Easy to short and explode in your face and dangerous as there's no finger guards for the careless or tired. Get a Fluke 120 for about 40 notes and treat yourself and stay safer :)

Further edit, they need an earth path to work....guess what that includes?

Thanks for both your replies. I like to touch a live first to check the bulb is working before turning the circuit off and re-checking. Just satisfies me that it is in fact off. The way you describe them sounds like a death trap. I am sure they must be safe to be on sale in the UK. Do you have evidence of them failing and causing death? (again, interested in the info, you are entitled to your views).

I had the consumer unit replaced with a split circuit RCD unit and he left me with tails to go to the first light/socket. I wired the rest in a new basement. He showed me how to wire the lights. He has been back to do a couple of other things and will have to return to sign-off the consumer unit and test at some point.

Sockets are simple. Lights more complicated, but the face plates are plastic anyway, so I'm not too concerned. I know the cables have been laid carefully which is the main thing.

I'm not a pro and can't check the Z's etc. However, I'm not doing this against the clock, so taking additional care to ensure it is all done correctly. It is being done when I am able, so over months and years. Getting an electrician out every time I wanted a socket threading through plasterboard would have been unrealistic. I also needed power/light to work.

I've had a zap from the mains before by poking a screwdriver into a fridge interior light to try and remove it in a rented flat many years ago. It wasn't pleasant and I have no desire to repeat it :)
 

Sonic67

Banned
In the UK you can get cheap cycle helmets. If you want them buy one. I am sure they are safe. If you have a ten pound head get a ten pound helmet as the saying goes.
 

njdbaxter

Prominent Member
bought new switch and ceiling rose with bulb cord.

unscrewed old switch and it only had a wire completely disconnected. didn't need to replace switch or ceiling rose, and not sure if I could be bothered taking them back to Homebase, just for £8
 

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