Numpty (me) damaged 2.5 TE cable in plastered wall

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StephenArfer

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I was adding some shelving supports in my study and totally ignored the obvious cable drop to the socket below. Not much of a flash/bang and and I stopped drilling when I heard the RCD trip. After taking a club hammer and chisel to the problem, it turned out that I had drilled through the plastic conduit and one conductor and damaged the insulation on the others. It clearly couldn't be left like that. There was plenty of free cable in the ceiling cavity so that was easy to pull through and I pulled a new section of T/E from the socket below to the now quite large hole in the wall. I decided to install a 2-gang pattress to cover the damage and join the cables with a choc block. I also took the opportunity to spur off a 5A supply for and additional light. See image below. I should mention that the other cable of the ring was untouched.

This was all at least a year ago, but now I would like to "bury the evidence" in the wall (I no longer need the 5A lighting spur). So at last I come to the point; What is the best (and electrically sound) way of joining the conductors without a junction block? I'm competent at soldering and could easily lap join and heat shrink sleeve, but I'm wary of using soft solder on a power circuit. I've quite a lot of experience using crimps on stranded wire low voltage installations (aircraft) and I have the appropriate ratchet crimping tool. However I'm not sure whether this type of crimp should be used on solid conductors. So, can I have some advice on the best and safest way of joining wires under this set of circumstances?

After joining the cables, I will provide some physical protection to cover the cut away section of conduit and then I would like to bury the joint in the wall by filling over the area.

Thanks for any advise on my best course of action to hide the evidence of my aberration for ever.



Numpty's wiring.jpg
 

StephenArfer

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That's correct. I want to conceal in what is a confined space and plaster over .

Thanks for all responses.
 

roys

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Can you not just pull in a new length of cable since it’s in conduit then no joints required.
 

Richard-the-ninth

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I bet its capping not conduit.

Wagos (in a box) are maintenance free, so yes bury in a wall no problem.

(I am not going to say about the 1.5 mm cable going to the FCU)
 

StephenArfer

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Yes, it is indeed capping, not conduit. Sorry if I misled anyone. I can't pull another full length though. It could be either the cable up the wall across the ceiling and down the opposite wall, or, the loop up into the ceiling and through the joists and down the same wall a few feet away. It would be easy to find out which but in either case I have no access to the ceiling void and not being familiar with pulling through solid core cable, I'm concerned that I'd get it stuck half way. Sod's law.

I would have to do a bit more excavation to bury a Wago, so I think I'll go with the soldering method the increased size of the finished joint will be no problem then. I might need some helping hands that can stick to the wall. :giggle:
 

Brobat

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I was adding some shelving supports in my study and totally ignored the obvious cable drop to the socket below. Not much of a flash/bang and and I stopped drilling when I heard the RCD trip. After taking a club hammer and chisel to the problem, it turned out that I had drilled through the plastic conduit and one conductor and damaged the insulation on the others. It clearly couldn't be left like that. There was plenty of free cable in the ceiling cavity so that was easy to pull through and I pulled a new section of T/E from the socket below to the now quite large hole in the wall. I decided to install a 2-gang pattress to cover the damage and join the cables with a choc block. I also took the opportunity to spur off a 5A supply for and additional light. See image below. I should mention that the other cable of the ring was untouched.

This was all at least a year ago, but now I would like to "bury the evidence" in the wall (I no longer need the 5A lighting spur). So at last I come to the point; What is the best (and electrically sound) way of joining the conductors without a junction block? I'm competent at soldering and could easily lap join and heat shrink sleeve, but I'm wary of using soft solder on a power circuit. I've quite a lot of experience using crimps on stranded wire low voltage installations (aircraft) and I have the appropriate ratchet crimping tool. However I'm not sure whether this type of crimp should be used on solid conductors. So, can I have some advice on the best and safest way of joining wires under this set of circumstances?

After joining the cables, I will provide some physical protection to cover the cut away section of conduit and then I would like to bury the joint in the wall by filling over the area.

Thanks for any advise on my best course of action to hide the evidence of my aberration for ever.


I’d crimp it, wrap in some self amalgamating tape, stick a bit of capping over the damaged bit and re-plaster. I’ve spoken to NICEIC helpline in the past and they were ok with crimping solid conductors.
 

Luckyboy

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Can you pull through up to above ceiling me make the joint in the ceiling/floor void?
I'd also suggest this, if possible, and then run a new length of T/E down to the socket.

Another alternative would be to add another socket outlet to the ring (at the height you've put this choc-block), then you wouldn't have to hide any junction in a wall or patch up the damage to the wall... just a thought.
 
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To make a good joint you will need to be able to pull some slack on the two cable ends..
and will need to cut back some plaster to give yourself enough cable to work with..

AND... If you are considering burying some sort of joint..
Then plastering / patching over and painting / decorating the wall..
(i.e. leaving a patch of some sort to make good part way down the wall.)

Then personally I would stop all this pi55ing in the wind and faffing about...

and just chase out the section of cable.. replace it..
then make joint(s) above ceiling / below floor, rather than a "Heath-Robinson" make-do, poor workmanship, joint mid-way up a wall...

The wall is going to need some redecorating anyway..
So why not do a better job and be 100% sure it will not come back to bite you at a later date..

Personally I've been trading self employed since Feb 1999...
During which time I have come across a reasonable share of damaged cables to replace..

And so far... I have NEVER had to bury any joints part-way up a wall..
BUT I have come across numerous failed buried joints during fault finding on various circuits!!!

So from my personal experience I would say it is a daft idea to consider a bury-the-joint option...
even if technically BS7671 is happy with inaccessible maintenance-free joints!

At the end of the day.. You-Pay-Your-Money, and Take-Your-Pick....
Even though what is permissible is not always the best solution.
 
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Unfortunately you just sometimes have to make a mess.......

This one was damaged when fitting a curtain rail bracket,,, unfortunately the wall was dot & dabbed without any capping or trunking so it needed to be cut out at the dabs.... I made the joint using Wago's in a Wiska box with stuffing glands in the ceiling void

IMG_2800.jpeg
 

StephenArfer

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Another alternative would be to add another socket outlet to the ring (at the height you've put this choc-block), then you wouldn't have to hide any junction in a wall or patch up the damage to the wall... just a thought.
Thanks for that very practical suggestion mate. That's the way I'm going to go. I'll fit a new back box and a 2 gang socket as you suggest. Plenty available to pull down and I can pull another section in from socket below if I need more slack.

I can use the new socket to power an adjacent WAP and network switch so with any luck it'll look as if it was always intended that way. The 5A spur will be going anyway.

Thanks to everybody who responded. It's nice to join a forum where such constructive advice is available.

Steve
 

Mike P

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Thanks for that very practical suggestion mate. That's the way I'm going to go. I'll fit a new back box and a 2 gang socket as you suggest. Plenty available to pull down and I can pull another section in from socket below if I need more slack.

I can use the new socket to power an adjacent WAP and network switch so with any luck it'll look as if it was always intended that way. The 5A spur will be going anyway.

Thanks to everybody who responded. It's nice to join a forum where such constructive advice is available.

Steve
That’s the way I would go. The good thing about it is the junction box will always be accessible. The only change I would make is to fit a split double back box so you can have a socket and a fused spur. It just gives you a bit more flexibility.
 

Mike.J

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If you are able to pull down from above and up from below, why can't you pull in a new length of cable and avoid a join?
 

StephenArfer

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That’s the way I would go. The good thing about it is the junction box will always be accessible. The only change I would make is to fit a split double back box so you can have a socket and a fused spur. It just gives you a bit more flexibility.
Good suggestion. That's the way I'll go then. Thanks again.
If you are able to pull down from above and up from below, why can't you pull in a new length of cable and avoid a join?
I can only pull down existing slack in the ceiling void. I have no access to lay new cable up there without more hassle than I want to get involved in.
 
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