Joining a cable to be buried in a wall

[SJD]

Now and again, I need to join a cable that is buried in a wall, sometimes in a stud wall, sometimes to be plastered over. Sometimes when someone has drilled through it (last one was a kitchen fitter who should have known better), or sometimes to extend a cable e.g. to move an accessory lower on the wall. Generally I'm thinking of 2.5mm2 or 1/1.5mm2 twin & earth. And assuming a new cable can't easily be pulled through.

What jointing method do people prefer?

I've used heatshrink crimp butt connectors plus an outer covering of glue-lined heatshrink. I worry about the crimp not gripping one of the conductors tightly enough and it coming loose.

I've also used heatshrink solder connectors, again with an outer glue-line h/s covering. If the copper is not clean enough, I worry about a dry joint to one of the conductors.

And what if one cable is new solid T&E, while the other cable is stranded imperial cable?

 

[Midwest]

And a side note about using blowtorches... make sure your insurance covers you for using them. When I took out mine, I was asked about hot tools, which included blowtorches, and whether I used them. I have a heat gun for shrinking which doesn't fit the hot tool category because it doesn't use flame.

My household insurance allows me to use one of these Master Class Deluxe Gas Kitchen Blow Torch Professional Cooks * Brand New * | eBay - https://www.ebay.co.uk/i/192097300088?chn=ps&dispItem=1&adgroupid=45192390362&rlsatarget=pla-331477173012&abcId=1129006&adtype=pla&merchantid=114891207&poi=&googleloc=1007245&device=c&campaignid=861899495&crdt=0 for my crème bulee. I just take the joint to my house, sorted

 

[SparkyChick]

I think I've been sucked into the double post issue! It posts but leaves the post to make you think it hasn't been. I thought you were all just careless!

Yes, it's a pain in the posterior, I've nearly fallen foul of it a few times. You click 'Post Reply', the little spinner widget appears in the top right corner to show it's working and then it just stays there. Maybe the scripts are timing out on the server or something?

(@Dan - Just to let you know, if you didn't already, there is an issue with posting)

 

[Midwest]

This worked for the Apollo 13 crew

 

[DPG]

This worked for the Apollo 13 crew
View attachment 37644

At least it has been PAT tested!

 

[Ian1981]

And a side note about using blowtorches... make sure your insurance covers you for using them. When I took out mine, I was asked about hot tools, which included blowtorches, and whether I used them. I have a heat gun for shrinking which doesn't fit the hot tool category because it doesn't use flame.

The only thing I use a blowtorch is for roasting marshmallows

 

[Midwest]

Also crème bulee and when you have no electrickery

 

[Des 56]

If your happy with the crimped or soldered joint,you could use a short length of plastic pipe to cover the joint,put adaptors on the ends to enable a stuffing gland to act as support
Personally I would be reluctant not to have a box and blank plate for enclosing the joint

 

[Pete999]

Is the damaged cable a switch drop or socket? Sorry just read the opening post, personally I would avoid joining if I could, if you are going to dig a dirty great hole in the wall to repair a cable, I would go the whole hog and replace the entire piece to where you can effect a decent MF joint that wont need burying in the plaster, I appreciate it's allowable, but not my cup of tea I'm afraid.

 

[Midwest]

There are times when there is no alternative, but to 'bury' a crimped or soldered joint. I did such when a chap drilled into cable above socket. Flat roof extension, filled with Celotex with no space for JB.

He was in the process of putting up a picture frame, we could of turned it into a bookshelf, I suppose

 

[SparkyChick]

If your happy with the crimped or soldered joint,you could use a short length of plastic pipe to cover the joint,put adaptors on the ends to enable a stuffing gland to act as support
Personally I would be reluctant not to have a box and blank plate for enclosing the joint

I suppose a small length of conduit with a couple of adaptors and glands on the end would be a good choice.

That's a nice idea and a great tip. Thanks

 

[davesparks]

And a side note about using blowtorches... make sure your insurance covers you for using them. When I took out mine, I was asked about hot tools, which included blowtorches, and whether I used them. I have a heat gun for shrinking which doesn't fit the hot tool category because it doesn't use flame.

Whereas the hot works section of my insurance does include hot air guns, the only thing it does not include is a soldering iron.

 

[SparkyChick]

Whereas the hot works section of my insurance does include hot air guns, the only thing it does not include is a soldering iron.

So much variation. Pays to check the fine print and ask lots of questions

 

[PeteNeale]

Thanks for acceptance into your forum, quite a few years into retirement now and just pottering around at home. Trying to replace some old wall lights where the connectors were embedded in the plaster and the connection was just twisted wire with a plastic cap pushed on, normal 1950s practice. I found a 2017 thread on the subject on the site and the information was invaluable. Thank you I will be using the site a lot just to keep up with current practice, but I am afraid I probably wont have much to contribute, thanks gentleman you have an excellent site here.

 

[telectrix]

one of these with heat shrink over.

 

[Spoon]

one of these with heat shrink over.
View attachment 58308

Do you have a link to one. Curious as to rating of them.