Hall Light Wiring Advice

[MattOzzy]

Hi all,

To cut a long story short, I have spent the last 18 months (since we moved in) trying to work out an issue with our hallway lighting.

It has a switch at the bottom of the hallway and one at the top with a pendant at either end. In order to turn the lights off, both switches would have to be in the off position, and couldn't be controlled by the other switch if one was in the on position.

After agonising over the wiring and checking it several times, I have found the issue - the black wire which runs between the two switches (connected to L2 on both) seems to be damaged although unsure where, or how. The house had an attic conversion done around 5 years ago which is above the hall and I guess it could have been damaged then.

The question: Is it best to leave it as it is, with the risk that there could be a nail which has penetrated the cable and is live and suffer with running up and down stairs repeatedly. Or, can I use the earth wire (currently connected to the back box) to run between L2 each end instead of the black wire. Which would be safest?

I appreciate that in the ideal scenario we would get the cable re-ran, but i'm also well aware that that will not be a cheap task considering we have no idea of what the damage actually is. My thoughts are that using the earth would be a wise option as the risk of the back box becoming live is minimal?!

Any advice would be hugely appreciated.

Many thanks
Matt

 

[sparkwright]

You can't use the earth wire.

Send pictures if you of the wiring in each switch. You never know, we may come up with a clever plan.

If you really think a cable is damaged though it needs repairing properly.

The pics will help us.

 

[MattOzzy]

Out of pure curiosity, is the reason for not being able to use the earth wire (aside the fact the back boxes wouldn't be earthed) down to the lack of insulation on the cable? As a proof of concept, I did try the earth wire in its place to verify whether there was a damaged wire between the two switches. Rest assured, It is all reverted now - wouldn't put either my family or our house at risk!

I know the cable doesn't work for one reason or another, but without pulling the floor up of the attic conversion and doing some investigatory work its not so simple. We do plan to do some work up there before too much longer so will do it all at the same time, but thats another story! At the end of the day, its been like this since we moved in. I appreciate it is far from ideal though.

Attached a pic of each switch, on the double switch it is the connection closest..

Many thanks

 

[winston1]

You cannot use the earth wire for anything other than an earth. It would be illegal, dangerous, and possibly invalidate your house insurance.

 

[MattOzzy]

Understood, have no intention to do so!

 

[sparkwright]

If you have one damaged wire in a cable, the other wires COULD be damaged too, just making enough contact to work at the moment.

Remote controlled switches may be the answer, for the moment, so you can completely disconnect the damaged cable for the moment.

The wiring looks shoddily done, by some kind of DIYer.

 

[endecotp]

In order to turn the lights off, both switches would have to be in the off position, and couldn't be controlled by the other switch if one was in the on position.

After agonising over the wiring and checking it several times, I have found the issue - the black wire which runs between the two switches (connected to L2 on both) seems to be damaged although unsure where, or how.

Just a break in that black wire would not explain the symptoms you experienced.
The damage would need to involve it being shorted to the brown wire in the same cable.
If this is due to a nail being driven through it, for example, then the nail is now live.

 

[ban-all-sheds]

Just a break in that black wire would not explain the symptoms you experienced.

Matt - FYI - this is what you were suggesting: