How do you test a uk 3 core wire to see if it's live

[bosco72]

Hello, How do you test a uk 3 core wire to see if it's live? The wire is high up and is sticking out of the porch ceiling with nothing on the end like it has just been cut. I would just like to cut it and patch over. directly below is the electricity meter so I'm guessing something was originally attached and the wire is not live. But I would like to test it to make sure.

I have one of those screw drivers with the bulb in but I've had it a long time wouldl that still be safe to use?

Cheers in advance

 

[EFLImpudence]

I have one of those screw drivers with the bulb in but I've had it a long time wouldl that still be safe to use?

No, they will not tell you for certain what is more important - that the wire is NOT live.

You need, at the very least, a two-pole multimeter set to A/C volts

with one probe connected to a known earth and

the other probe, in turn, to each of the conductors.

 

[bosco72]

I can get a multimeter not sure I can find an earth as its quite high up, any ideas?

I have one of those screw drivers with the bulb in but I've had it a long time wouldl that still be safe to use?

No, they will not tell you for certain what is more important - that the wire is NOT live.

You need, at the very least, a two-pole multimeter set to A/C volts

with one probe connected to a known earth and

the other probe, in turn, to each of the conductors.

 

[Diyisfun]

Cheap option (probably get shot down) put the wires in a terminal block, tape over it, pock back in the ceiling.

 

[mattylad]

Attach a length of wire to one probe that allows you to get to an earth then.

 

[ericmark]

We all I am sure at some time we have all used the testers with reed switches in tip or neon screwdrivers as quick or second test to find if a wire is live but this is not the way it should be done.

The big problem with any unknown wire is even using a approved tester and proving unit it could become live latter when something is switched and however much care is taken it could still become live latter.

There is only one safe method and that's to remove the cable. However where that's not an option then consider it is live and insulate. Where I can I fold the cable so end is sheaf not a wire so unlikely to stick out of the end.

Theory is we should not use insulation tape as it can be removed without a tool but some times we just have to use some common sense. Same applies to having something to show where cables run. So in theory you need to fit a ceiling rose so anyone can see there is a cable there or remove it completely but in practice I would tape it up and push it out of the way up the hole.

But be very away even if you do use a meter and have a wandering lead connected to earth it still can't be proved dead. You can only prove it to be live. So why bother? I would insulate and hide although I should not be telling you that.

 

[bosco72]

Not sure I can hide it, it is just sticking out of the corner of the ceiling? I can not believe there is no safe and easy way to test? Do I need specialist equipment? Or do I need to get a electrition in?

We all I am sure at some time we have all used the testers with reed switches in tip or neon screwdrivers as quick or second test to find if a wire is live but this is not the way it should be done.

The big problem with any unknown wire is even using a approved tester and proving unit it could become live latter when something is switched and however much care is taken it could still become live latter.

There is only one safe method and that's to remove the cable. However where that's not an option then consider it is live and insulate. Where I can I fold the cable so end is sheaf not a wire so unlikely to stick out of the end.

Theory is we should not use insulation tape as it can be removed without a tool but some times we just have to use some common sense. Same applies to having something to show where cables run. So in theory you need to fit a ceiling rose so anyone can see there is a cable there or remove it completely but in practice I would tape it up and push it out of the way up the hole.

But be very away even if you do use a meter and have a wandering lead connected to earth it still can't be proved dead. You can only prove it to be live. So why bother? I would insulate and hide although I should not be telling you that.

 

[bosco72]

That was my initial thought but there is no room for it to go into especially with a block on it.

Cheap option (probably get shot down) put the wires in a terminal block, tape over it, pock back in the ceiling.

 

[ban-all-sheds]

You really ought to trace it back and disconnect it at the other end.

The wire is high up and is sticking out of the porch ceiling with nothing on the end like it has just been cut.

Are there any light switches nearby which do nothing?

 

[ericmark]

No equipment can test a unknown cable and say this cable will never become live.

The more experience the tester has the more likely it is that his results will be correct. but no one can 100% be sure the cable is dead without finding the other end of the cable.

In an ideal world all installations will have an installation certificate or a minor works certificate detailing what they do and where they run but we don't live in an ideal world and we can only P with the C we have and so at the end of the day it's down to a risk assessment.

There is no black and white one has to make that executive decision be it right or wrong. That's why we have insurance.

So only option is to employ someone whose insurance will cover should it be other than expected.

 

[PrenticeBoyofDerry]

How do you test a uk 3 core wire to see if it's live?

You need a two pole approved voltage indicator, to be sure.
Something like this would do http://www.kewtechcorp.com/products/electrical_testing/KEWVOLT1.htm

The wire is high up and is sticking out of the porch ceiling with nothing on the end like it has just been cut. I would just like to cut it and patch over. directly below is the electricity meter so I'm guessing something was originally attached and the wire is not live. But I would like to test it to make sure.

Don't just patch over it until you have proved it is dead, and it can not be re-energised.

I have one of those screw drivers with the bulb in but I've had it a long time would it still be safe to use?

Not something that I would ever consider safe to use, regardless of age.

As already mentioned, it is one thing confirming it is dead but another thing preventing it becoming live again. When the cable is hidden and no one knows it is there and it still has the potential to become live, that then becomes a potential hazard, so must be prevented.
So I would be identifying the circuit, this may mean tracing it back to the consumer unit, using continuity tests.
Then find the most convenient point where the supply to this cable can be disconnected without interfering with the rest of the circuit, if it is still in use.
http://www.esc.org.uk/fileadmin/user_upload/documents/industry/best_practice/BPG2_09.pdf
http://www.youtube.com/watch?v=g_5irKWf18s

 

[letinman]

get an electrician because it may be dead now then become live later as Eric says, i would not risk a cover up job on this , i would charge £45 as a call out and would most likely remedy in the hour so i expect you can get this sorted for similar

 

[bosco72]

The only electrical thing on that side or near the cable is a double plug socket on the same wall in roughly the same position in the room above, next time I'm at the house I will test the sockets to see if live. And I will feed back my findings.

 

[ban-all-sheds]

The only electrical thing on that side or near the cable is a double plug socket on the same wall in roughly the same position in the room above, next time I'm at the house I will test the sockets to see if live.

But not with this:

I have one of those screw drivers with the bulb in

And I will feed back my findings.

I'll respond to your feedback in advance.

Unless you know that the cable in the porch ceiling comes from that socket then knowing whether the socket is live or dead is of no use whatsoever in determining whether that cable is, or could become, live.

And if you do know that it comes from the socket you can disconnect it and ideally remove it. If you can't remove it then cut it back as far as possible.

 

[bosco72]

I was simply going to cut the power and do some wire jiggling like I would do on a server rack to locate the correct cable. At no point am I going to risk injuring myself over a power cable.