Fixing unsheathed twin and earth

[Spudders]

Under my floorboards I have a short section of twin and earth which is unsheathed. The outer grey coating has been stripped over a 10 cm length and the two inner red and black coatings have been stripped over a 2-3cm length to expose the copper cables. The cable has no marking to indicate the size but the copper is stranded and I'd say it's 6mm cable (from my very limited experience). I don't know where the cable runs to but there isn't an electric shower and it's not to the cooker/hob so it can only be for plug sockets.

What is my best course of action? I've wrapped the exposed cable with electrical tape and turned the power off as the house is being renovated and I'm staying at my parents while it's being finished. Will I need to cut the wire and fit a junction box and if so I presume a 60a maintenance free one?

The cable must have been in this state for some time. I only noticed when I was securing a squeaky floorboard and moved a cable out of harm's way only to hear a pop from the other side of the room where I tugged on it and caused the exposed copper to touch the earth wire.

Many thanks

 

[GBDamo]

Could be redundant cable.

You really need to determine if it is live and if so what it is for.

I personally would prove its dead, cut it and get chock blocks on each end before re-energising to see if it is still in use. If it is still in use then reconnect inside a maintenance free junction box, ensuring that all unscathed cable is inside the JB.

If you don't have enough slack to do this you will have to determine the size of the cable before using a second JB to insert a new section of cable.

 

[westward10]

I think you are going to need an electrician to verify if it is live or can be made live.

 

[ipf]

Could be redundant cable.

You really need to determine if it is live and if so what it is for.

If it he heard a 'pop', I don't think it was a champagne cork........!!
Help needed fast.

 

[Spudders]

Thanks for the quick reply.

I have a fair amount of slack so have plenty to play with. I'll give that a go. If it does turn out to be 6mm do I need a 60a box? I've got a 32a Hager one which I found in a box of stuff left by the previous owner but wasn't sure if that would be sufficient for the cable size, even if the cable only serves plug sockets.

Thanks.

 

[telectrix]

could be 7/029? if so, one of these with heatshrink would fix without the need for much slack:
https://www.toolstation.com/in-line-spring-lever-connectors/p78346

 

[stevethesparks]

I'd also be asking why the insulation is missing - rodent problem?
2 -3 cm length

 

[Spudders]

I'd also be asking why the insulation is missing - rodent problem?
2 -3 cm length

No, there's no sign of rodents, the sheathing/insulation has been cut relatively cleanly and the lighting cable is next to it but hasn't been touched.

Maybe the previous owners wanted to spur off for something, stripped it and realised they got the wrong cable and just left it. It's not the only thing that's left me scratching my head. Blu-tack as wood filler is my favourite so far.

 

[7029 dave]

Any chance of taking a photo.

 

[Spudders]

Any chance of taking a photo.

 

[Dartlec]

It sounds like the old practise of running through a junction box without cutting the cable, to spur another cable - but perhaps the cable was removed or never used.

You or someone does need to trace it, as if it's redundant it can be safely isolated and left. If it isn't then with a cable of that age it might be a good time to replace it while you're renovating anyway, to avoid any issues in the future

 

[7029 dave]

Yes does look like someone has spliced into it, then changed their minds, needs turning into a MF jb.

 

[Dartlec]

Hard to tell the scale, but that doesn't look like 6mm to me. It may be if it's traced that it's 4mm on a 30A fuse or 32A breaker, in which case any of the 32A MF junctions boxes should suffice.

Assuming it's metric, then the giveaway may be the cpc size - 6mm has a 2.5mm earth, 4mm has 1.5mm - if it's imperial then it's a different matter, though that doesn't look quite that old from the pic at least.

Not sure I've seen a maintenance free junction box rated more than 32A though if it is 6mm.

 

[Spudders]

Thank you for your replies and advice. I'll take a look at the earth tomorrow. The cable isn't quite as chunky as another bit of 6mm I've got in the house but it's a a lot bigger than the 2.5mm. The cable itself didn't give any indication as to the size, it just says "Volex Salford".

I've got an electrician coming soon to wire the cooker/hob cables into the fuse board but that won't be for a couple of weeks. I was hoping this would be a quick and straightforward job I could do myself before then so I could get the floorboards fixed in place and carpets laid but I can wait for him to check it out if needs be.

 

[westward10]

Yes does look like someone has spliced into it, then changed their minds, needs turning into a MF jb.

Definitely the cut through the line and neutral insulation is staggered.

 

[Dartlec]

Thank you for your replies and advice. I'll take a look at the earth tomorrow. The cable isn't quite as chunky as another bit of 6mm I've got in the house but it's a a lot bigger than the 2.5mm. The cable itself didn't give any indication as to the size, it just says "Volex Salford".

I've got an electrician coming soon to wire the cooker/hob cables into the fuse board but that won't be for a couple of weeks. I was hoping this would be a quick and straightforward job I could do myself before then so I could get the floorboards fixed in place and carpets laid but I can wait for him to check it out if needs be.

Given that the cable isn't broken the important thing is to protect it from touching and shorting if it may still be live. You seem to have managed that temporarily, but will need something more pemanent before the carpet goes down.

I wonder whether If it could be put into one of the old circular junction boxes, then that may be enough - the point of a maintenance free junction box is that the terminals can't come loose - but in this case there are no 'terminations' as the cable is still complete. The point is to safely insulate the cable.

But if the electrician will be working then he will be signing things off so it should probably be his decision. It might be a case of asking the electrician to pop in earlier, even if briefly - it shouldn't be a long job.

 

[7029 dave]

Given that the cable isn't broken the important thing is to protect it from touching and shorting if it may still be live. You seem to have managed that temporarily, but will need something more pemanent before the carpet goes down.

I wonder whether If it could be put into one of the old circular junction boxes, then that may be enough - the point of a maintenance free junction box is that the terminals can't come loose - but in this case there are no 'terminations' as the cable is still complete. The point is to safely insulate the cable.

But if the electrician will be working then he will be signing things off so it should probably be his decision. It might be a case of asking the electrician to pop in earlier, even if briefly - it shouldn't be a long job.

Good shout about using J201 joint box, the cable is still in one piece.

 

[ipf]

Thank you for your replies and advice. I'll take a look at the earth tomorrow. The cable isn't quite as chunky as another bit of 6mm I've got in the house but it's a a lot bigger than the 2.5mm. The cable itself didn't give any indication as to the size, it just says "Volex Salford".

I would say sixties, seventies cable. It looks like a solid earth so I would say, metric, 4.0mm, maybe.

It's interesting, Volex was the trade name of Ward and Goldstone, a big manufacturer based in Salford. Their cable wasn't bad but their general accessories were known by us as 'cheap Ward and Goldstone crap'....the equivalent of Proteus today, I suppose, but they didn't get into distribution equipment. No cheap circuit breakers around in those days.
Just a point.