UK Looking for help - Trying to move a light switch but I think the cable I’ve bought is defective

[Scott smit]

Looking for a little advise as I’m not sure what’s happening

So I’m looking at moving a two way light switch probably about 100cm away from its current location as it’s obstructed

So I bought PRYSMIAN 6243YH three core and bare earth wire When I wired the existing switch connections up to the new cable I notice that the earth wire was live?

This didn’t seem right to me so I hooked up the bare earth wire to the switch live and notice that this caused all three cores to be live?

This video might show what I’m trying to explain will also mentioned that the other end of the cable is not connected to anything and the wires are not touching

Streamable Video

Watch this video on Streamable.

streamable.com

 

[Avo Mk8]

That is a classic example of the capacitance between the cable conductors enabling a small current to light the neon tester. (You might notice the neon is brighter when applied to the live wire, and slightly dimmer when applied to the other wires, showing the coupling capacitance that's in circuit)
If using a dead tester it would not show live.

There's likely nothing wrong with the cable. That's what neon testers do - confuse people!
If you have a multimeter you can check continuity between the cores, and I'm willing to bet you'll find the cable OK.

If you were "measuring" the earth wire when it was wired up, but the earth wire was not connected to anything, the same effect of lighting neon could happen. If the earth wire was connected to earth, and the neon lit, you have a earth fault.

PS I appreciate that's an experiment in the photo, but connecting live mains to the bare earth wire of a length of 3 core+e is not the safest thing to be doing. Just wire the cable up as intended.

 

[Scott smit]

That is a classic example of the capacitance between the cable conductors enabling a small current to light the neon tester. (You might notice the neon is brighter when applied to the live wire, and slightly dimmer when applied to the other wires, showing the coupling capacitance that's in circuit)
If using a dead tester it would not show live.

There's likely nothing wrong with the cable. That's what neon testers do - confuse people!
If you have a multimeter you can check continuity between the cores, and I'm willing to bet you'll find the cable OK.

If you were "measuring" the earth wire when it was wired up, but the earth wire was not connected to anything, the same effect of lighting neon could happen. If the earth wire was connected to earth, and the neon lit, you have a earth fault.

PS I appreciate that's an experiment in the photo, but connecting live mains to the bare earth wire of a length of 3 core+e is not the safest thing to be doing. Just wire the cable up as intended.

So even though the tester screwdriver is light up it’s probably not actually live?

Could it be possible that I’ve put purchased the wrong cable this photo is of the cable I bought and the light switch wiring currently

Also not sure if this helps this is the video I took when I was trying to test my wiring before putting it into the wall for the light switch when I noticed that the earth was showing live

Streamable Video

Watch this video on Streamable.

streamable.com

As you said it was not wired to earth in the video it was just disconnect

 

[Scott smit]

please delete this I edited into last post

 

[Avo Mk8]

So even though the tester screwdriver is light up it’s probably not actually live?

it's not 'live' in that it can't support much current, so not dangerous, and when it's connected that effect will go away!

Could it be possible that I’ve put purchased the wrong cable this photo is of the cable I bought and the light switch wiring currently

that is the correct cable.

Also not sure if this helps this is the video I took when I was trying to test my wiring before putting it into the wall for the light switch when I noticed that the earth was showing live
As you said it was not wired to earth in the video it was just disconnect

You will need to connect the earth wire to earth and run it to the new switch position, even if it's in a new plastic box and the switch doesn't require an earth.

When you move the light switch remember to run the cable in an allowable zone, ie horizontal from the previous socket.
Look up 'cable zones' if not familiar. I'd suggest putting a blanking plate over the old box to maintain legitimate zones for the wiring. If you want to plaster over the old position, and the wiring is in the wall, that could be a zone issue (ie if there's a cable going down to the old light switch, that will no longer be in a visible zone, so not to regulations. Also you would need a 'maintenance-free' junction box, and to install it competently, but hopefully you know all this.

 

[Scott smit]

it's not 'live' in that it can't support much current, so not dangerous, and when it's connected that effect will go away!

that is the correct cable.

You will need to connect the earth wire to earth and run it to the new switch position, even if it's in a new plastic box and the switch doesn't require an earth.

When you move the light switch remember to run the cable in an allowable zone, ie horizontal from the previous socket.
Look up 'cable zones' if not familiar. I'd suggest putting a blanking plate over the old box to maintain legitimate zones for the wiring. If you want to plaster over the old position, and the wiring is in the wall, that could be a zone issue (ie if there's a cable going down to the old light switch, that will no longer be in a visible zone, so not to regulations. Also you would need a 'maintenance-free' junction box, and to install it competently, but hopefully you know all this.

Perfect okay thanks so much I did what you said and wired up the earth this time and everything appears as I would expect no neon lights on the tester and all safe to touch

Yes I intended to run the cable horizontal ally and also put a blank face plate on the existing switch but thank you for pointing out

I planned on using terminal strips for connection of the new wire but if you have any suggestions on what would be better please let me know it’s really appreciated

 

[Avo Mk8]

I planned on using terminal strips for connection of the new wire but if you have any suggestions on what would be better please let me know it’s really appreciated

I would use 'Wago' connectors. Just Google 'Wago' if you don't know them. Beware of imitations, although it seems others here get on with alternative makes OK.
The Wago option would be a bit more expensive than terminal strips, especially if you have some strips to hand, and there's nothing wrong with using them, as long as no bare copper showing, and they are done up correctly!

 

[Scott smit]

I would use 'Wago' connectors. Just Google 'Wago' if you don't know them. Beware of imitations, although it seems others here get on with alternative makes OK.
The Wago option would be a bit more expensive than terminal strips, especially if you have some strips to hand, and there's nothing wrong with using them, as long as no bare copper showing, and they are done up correctly!

Okay perfect thanks for all the help and advise really appreciated will send an update when project is finished

 

[Scott smit]

Well pretty much finished with this project now just the wall is left to repair I’ve added pictures so you can see if there’s anything you would like to let me know please feel free much appreciated

I used some electrical tape around the terminal strips to ensure nothing will touch other cables unfortunately didn’t have all of the colours to hand to just used green

 

[Avo Mk8]

Well pretty much finished with this project now just the wall is left to repair I’ve added pictures so you can see if there’s anything you would like to let me know please feel free much appreciated

I used some electrical tape around the terminal strips to ensure nothing will touch other cables unfortunately didn’t have all of the colours to hand to just used green

Thanks for coming back.
I think I'm right in saying you have connected the earth conductors to the old wall box?
It would be desirable to put full length green/yel sleeving on all those bare earth wires if you can. Otherwise, looks good to me!

 

[Scott smit]

Thanks for coming back.
I think I'm right in saying you have connected the earth conductors to the old wall box?
It would be desirable to put full length green/yel sleeving on all those bare earth wires if you can. Otherwise, looks good to me!

Firstly just wanted to again thank you for all your help I really appreciated it couldn’t have done it without you

I connected the earth wires to both the old box and the new box as I thought that made the most logical and safe sense

Yes I’ll try to put some sleeving on them would electrical tape be just as good if can’t find any small packs of sleeving?

 

[Avo Mk8]

Firstly just wanted to again thank you for all your help I really appreciated it couldn’t have done it without you

I connected the earth wires to both the old box and the new box as I thought that made the most logical and safe sense

Yes I’ll try to put some sleeving on them would electrical tape be just as good if can’t find any small packs of sleeving?

Personally I hate 'insulation' tape. You come back years later for maintenance or whatever and everything is sticky and gunky to work on, and you get the stick on the bare ends of the wire and then wonder if the terminal connection will be poor as a result. Horrible!
Spoil yourself and do it nicely with sleeving!

 

[loz2754]

Personally I hate 'insulation' tape

Agreed. I don't think it should be sold as insulation tape. Maybe electrician's tape...