HELP! is my metal ceiling light live?

[worried]

Recently bought a none contact voltage tester and decided to use it on a few things around the house but a metal bedroom light is lighting up red and beeping to say the light is live. I have tried it on all of the parts of the light and it lights up everywhere. I am too scared to touch the metal light now. I tried it on 2 other metal lights downstairs but it did not beep or light up. Can anyone help? Thanks

 

[westward10]

Non contact voltage testers can give misleading indication however they generally do not indicate through metalwork to the contained conductors. Is it lighting on the black tubework.

 

[swaRRR]

These are not accurate.

Your best bet is to get someone out to have a look, but if you're interested in this sort of thing an actual voltage and continuity tester is a better investment.

 

[worried]

Non contact voltage testers can give misleading indication however they generally do not indicate through metalwork to the contained conductors. Is it lighting on the black tubework.

Hi, yes it lights up on that part too.

 

[westward10]

Hi, yes it lights up on that part too.

In that case I would be getting someone to have a look.

 

[worried]

These are not accurate.

Your best bet is to get someone out to have a look, but if you're interested in this sort of thing an actual voltage and continuity tester is a better investment.

Thanks for the reply. I do have a KEWTECH KT1780 if that would help double check if the metal part is live but not sure how to use it to check.

 

[Dartlec]

Recently bought a none contact voltage tester and decided to use it on a few things around the house but a metal bedroom light is lighting up red and beeping to say the light is live. I have tried it on all of the parts of the light and it lights up everywhere. I am too scared to touch the metal light now. I tried it on 2 other metal lights downstairs but it did not beep or light up. Can anyone help? Thanks

As @westward10 says, non contact voltage testers can only give an indication, which isn't always accurate unless you interpret them correctly.

That looks suspiciously like a LAP tester, which in my experience are not very good quality either so I wouldn't necessarily trust it, though it makes sense to be sure it is safe.

Is the ceiling light on in the picture, it's hard to tell? If it is, do you get the same reading with the light off?

Was it installed by someone who knew what they were doing? It's possible that it's been installed with reverse polarity, so that the neutral and live are crossed - which could mean it might detect the 'live' through the metal even with the light off - though likely only if the metal is thin, or perhaps not metal at all.

The only immediately dangerous option would be that if the earthed metal had become live, in which case it should be installed in a way that would trip the mcb or RCD in the consumer unit.

Is the lighting circuit on an RCD in the consumer unit/fusebox?

it's hard to diagnose any further without a 2 pole tester used correctly to get an accurate view of the installation. If you're unsure it may well be worth getting an electrician to pop in and check, particularly if the installation has never been tested.

 

[westward10]

Problem here is that you would need a known earth you use the tester and if the metalwork is actually live that suggests the fitting is not effectively earthed and other parts of the circuit may not be. Advising how to use your other tester isn't something I would be doing due to the hazards involved so you be best getting an electrician involved. It may be turn out to be the quirks on a non contact tester although as I say it is unusual for them to indicate through metalwork.

 

[worried]

As @westward10 says, non contact voltage testers can only give an indication, which isn't always accurate unless you interpret them correctly.

That looks suspiciously like a LAP tester, which in my experience are not very good quality either so I wouldn't necessarily trust it, though it makes sense to be sure it is safe.

Is the ceiling light on in the picture, it's hard to tell? If it is, do you get the same reading with the light off?

Was it installed by someone who knew what they were doing? It's possible that it's been installed with reverse polarity, so that the neutral and live are crossed - which could mean it might detect the 'live' through the metal even with the light off - though likely only if the metal is thin, or perhaps not metal at all.

The only immediately dangerous option would be that if the earthed metal had become live, in which case it should be installed in a way that would trip the mcb or RCD in the consumer unit.

Is the lighting circuit on an RCD in the consumer unit/fusebox?

it's hard to diagnose any further without a 2 pole tester used correctly to get an accurate view of the installation. If you're unsure it may well be worth getting an electrician to pop in and check, particularly if the installation has never been tested.

Hi, it is a LAP tester.

The light is off and the tester lights up while its off. [The light does switch on and work]

The consumer unit has 2 rcds [1 for one half and the other for the rest] nothing has tripped.

 

[Dartlec]

Hi, it is a LAP tester.

The light is off and the tester lights up while its off. [The light does switch on and work]

The consumer unit has 2 rcds [1 for one half and the other for the rest] nothing has tripped.

Ok, the fact that you have RCDs is one reason to worry a little less, as I assume there have been no trips? However, the light may not have been installed correctly and an RCD not tripping is not a guarantee that things are safe.

The fact that it detects on this light when off, and not the others, suggests that something is not quite right and it would be best to get it accurately diagnosed.

It would take an electrician less than 30 minutes to confirm whether anything is wrong here and it sounds like it would be a worthwhile investment for peace of mind at least.

 

[worried]

As @westward10 says, non contact voltage testers can only give an indication, which isn't always accurate unless you interpret them correctly.

That looks suspiciously like a LAP tester, which in my experience are not very good quality either so I wouldn't necessarily trust it, though it makes sense to be sure it is safe.

Is the ceiling light on in the picture, it's hard to tell? If it is, do you get the same reading with the light off?

Was it installed by someone who knew what they were doing? It's possible that it's been installed with reverse polarity, so that the neutral and live are crossed - which could mean it might detect the 'live' through the metal even with the light off - though likely only if the metal is thin, or perhaps not metal at all.

The only immediately dangerous option would be that if the earthed metal had become live, in which case it should be installed in a way that would trip the mcb or RCD in the consumer unit.

Is the lighting circuit on an RCD in the consumer unit/fusebox?

it's hard to diagnose any further without a 2 pole tester used correctly to get an accurate view of the installation. If you're unsure it may well be worth getting an electrician to pop in and check, particularly if the installation has never been tested.

Hi, it is a LAP tester.

The light is off and the tester lights up while its off. [The light does switch on and work]

It was installed

 

[Aaron b]

My little boy ran around once probing things with my fluke one and had I lighting up an some 5v items. I wouldn't be surprised if you have a broken cpc and see a voltage from the leakage from LED's.

 

[worried]

Hi, thanks for all the replies. I just tried the tester on other cables [including unplugged appliances] and it is also beeping on them. So I think this tester is faulty but I will get an electrician to check for peace of mind. Thanks

 

[Carolina]

Hi glad you'll check with a pro, these testers can sometimes be too sensitive, I have two and one of them lights up even when pointing at an appliance or my computer at about 10cm while the other one only does when you probe a wall socket or touch an actual live wire or faulty fixture.

 

[timhoward]

Hi, it is a LAP tester.

The light is off and the tester lights up while its off. [The light does switch on and work]

The consumer unit has 2 rcds [1 for one half and the other for the rest] nothing has tripped.

For extra peace of mind in meantime, press the test buttons on the RCDs and check they work. They benefit from occasional exercise and I’ve known them to stick.

 

[Sapper]

Does this light have two switches? There's two wiring methods for two way switching that I use (yeah, old skool). One of the methods can leave both feed wires 'live' while the light will be off. Flip both switches and test again.

 

[telectrix]

all good suge=gestions. as regards voltsticks, would to try to trace a ECU error on a 2022 Mercc. with a neon screwdriver. / NOPE, YOU'S USE A PROPER DIAGNOSTIC ANANYSER.

 

[Carolina]

Does this light have two switches? There's two wiring methods for two way switching that I use (yeah, old skool). One of the methods can leave both feed wires 'live' while the light will be off. Flip both switches and test again.

Hi, is that allowed? I'm in a course and my instructor said it could be dangerous if both contacts on the holder become live and someone unscrews (E26) a lightbulb and accidentally touches the cap and the ceiling/wall at the same time, closing a circuit. I won't do that but someone who doesn't knows might.

 

[swaRRR]

Does this light have two switches? There's two wiring methods for two way switching that I use (yeah, old skool). One of the methods can leave both feed wires 'live' while the light will be off. Flip both switches and test again.

Can you give a drawing for that?

All feed wires are permanent lives it's only the switch wire that is dead when the light is turned off.

Normally on say, pendants or battens, the perm live will go to each light on the run and then an individual switch wire goes from the rose to each switch from each fitting. Can't picture the way you're saying.

 

[Carolina]

Can you give a drawing for that?

All feed wires are permanent lives it's only the switch wire that is dead when the light is turned off.

Normally on say, pendants or battens, the perm live will go to each light on the run and then an individual switch wire goes from the rose to each switch from each fitting. Can't picture the way you're saying.

Feed L+N to both switches then run a single wire from each switch to the light.
When the light is off there's a chance both contacts on the lamp holder are live because both switches are hitting their respective live contacts instead of the neutrals.

It's easier and cheaper to do in older installations as you don't have to route as much wires as with the "proper" way.

I believe that's what he's doing.

edit: here's what I'm thinking about. I used aussie sockets because they're the ones the software comes with, imagine you have the sockets then and want to add a 2-way switch in the same box, that's a way of doing it