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?

 

[richy3333]

Speaking of heat shrink, can anyone recommend a decent heat gun which isn't mains fed?

I use a Milwaukee one and it works fine - 18V

 

[telectrix]

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

GO ONTO TOOLSTATION. THINK THEY ARE 32a.

 

[Spoon]

GO ONTO TOOLSTATION. THINK THEY ARE 32a.

Pardon... . . ?

Just for info people.

In Line Spring Lever Connectors

Use these 32A spring lever connectors for an easy, fast-fit connection. The levers are a real time-saver, and the compact design makes them easier to work with in confined spaces.• 3 in 3 out inline lever connectors• Spring levers for easy, fast-fit connections• Colour-coded for live, neutral...

www.toolstation.com

 

[pc1966]

I use a Milwaukee one and it works fine - 18V

Useful to know! I had wondered how long / how hot a battery gun would work for, as already have some 18V Milwaukee stuff, to decide if worth getting one at some point. Mostly I have used a mains powered gun from RS (donkey's years old) as generally not needed on-site.

 

[richy3333]

@pc1966 It works great. We no longer carry a mains one on the van. If I recall it was only about £99 as a bare unit off Amazon

 

[Dustydazzler]

Architrave box and wagos , blank plate

job done

 

[Snailspark]

Ideal SpliceLine In-Line Wire Connectors Pack of 10 - http://www.screwfix.com/p/ideal-spliceline-in-line-wire-connectors-pack-of-10/42201?tc=UA4&gclid=CjwKCAjw8IXMBRB8EiwAg9fgMMC5bZQx9nkRlCzGy2bhq4kNiU68RBD4nuIFrr9jlGvBMQu4GWYpzxoCjc0QAvD_BwE&gclsrc=aw.ds&dclid=COepqMCvudUCFYnjGwod3tIFFA Use these...stagger them and heat shrink.

I’ve used those a few times - keeps it nice and straight if you don’t have much slack

 

[Mike Johnson]

Bought one of these recently, with the deflector on it works surprisingly well: View: https://www.amazon.co.uk/Heat-Shrink-Tubing-Mini-Cordless/dp/B0064DGZPG/ref=sr_1_37?adgrpid=88288090060&dchild=1&gclid=EAIaIQobChMI8rLDkcrM6QIVNYBQBh0ykAG1EAAYASAAEgKh-vD_BwE&hvadid=408218351486&hvdev=c&hvlocphy=1007076&hvnetw=g&hvqmt=e&hvrand=7080332380222985000&hvtargid=kwd-359346914070&hydadcr=26613_1931084&keywords=butane+heat+shrink+gun&qid=1590326036&sr=8-37


I also bought a hydraulic crimper, bit awkward in tight spaces, but again extremely competent in squashing inline crimps: View: https://www.amazon.co.uk/HSEAMALL-Hydraulic-Crimping-Electric-Terminal/dp/B07VBMMDDT/ref=sr_1_1_sspa?crid=N7IDSW4HWEOI&dchild=1&keywords=hydraulic+crimping+tool&qid=1590326217&sprefix=Hydrolic+crim%2Caps%2C198&sr=8-1-spons&psc=1&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUFLRDkwVTBIQlRENjAmZW5jcnlwdGVkSWQ9QTAzMDU3NzYzU1ZPVDNSUVk5RENMJmVuY3J5cHRlZEFkSWQ9QTA4NjE0ODczMUhaOFBQR0YyRzRHJndpZGdldE5hbWU9c3BfYXRmJmFjdGlvbj1jbGlja1JlZGlyZWN0JmRvTm90TG9nQ2xpY2s9dHJ1ZQ==

 

[Pete999]

What size cables are you intending to crimp Mike?

 

[Mike Johnson]

one of these with heat shrink over.
View attachment 58308

Surprising how these have now become acceptable, when I first posted about them, there where subject to all sorts of disparaging remarks, one even that the yellow lever should have been stripped green.
[automerge]1590326642[/automerge]

What size cables are you intending to crimp Mike?

The inline crimps I have for 2.5mm are impossible to squash with a hand crimper: 2.5mm² Blue Butt Connectors - https://www.tlc-direct.co.uk/Products/CTBUTTslashB.html the above unit makes short work of it.

 

[Andy-1960]

In a scenario of cable being drilled into for example, as a last resort the cable can't be replaced, joint can't be left above wall unit etc (Wago), I've used butt connectors & heat shrink, as you've suggested. I bought some of these, but not used them yet;
View attachment 37629

They'll be some arguing against using crimp connectors on solid cables, but I've seen that disputed on another forum.

PS Lets not have any book shelf jokes

Big Clive on YouTube tested these recently and as I recall was not too impressed with the results. The solder does not seem to flow into the connection too well. Think they are ok for low current applications, but that’s about all.

 

[telectrix]

i've experimented with some of those solder connectors. the plastic melts before the solder. IMO..... RUBBISH.