soldering short cable

[emphasis303]

Hi guys

In the process of adding new sockets to my ring and one of the wires is a bit short, I tried connector strips and have them right against the back of the backbox however as it is a 25mm backbox the socket does not fit properly and sticks out.

So i remember reading on here about others soldering the short cable to a new length of cable and this i feel would suit me perfectly.

If you could please let me know whether its ok to just use normal leadfree plumbing solder and also whether i should use flex to solder to the 2.5mm twin and earth, and once i do this what would the next step be?

thanks a lot

 

[ban-all-sheds]

Lead-free or leaded. Doesn't the latter melt at a lower temperature? If so that's preferable.

Don't use flex - use more T/E.

You'll need heatshrink tubing for each core, and prepare each end by stripping back the insulation by a couple of cm and then bending each end double, hooking them together (this gives tensile strength to the join) and gently forming with pliers to make the joint as neat as possible.

Solder, inspect the joints, slide down the heatshrink tube & shrink it.

If there's room, something over the whole thing - large heatshrink or self-amalgamating tape.

 

[CallEdsFirst]

Not to start on Ban again, but, what's wrong with through crimps and a bit of heatshrink?

 

[ban-all-sheds]

Nothing.

 

[DESL]

Not to start on Ban again, but, what's wrong with through crimps and a bit of heatshrink?

To be fair OP asked about soldering.

And by the nature of his question it sounds like he has limited space which could be difficult getting the jaws of crimping tool in position to make an effective joint.

 

[stargazer]

Also I would have thought that a well-made soldered electrical connection will be more reliable than crimps.
Isn’t there an analogy with plumbing here?
A soldered connection in copper pipes is much less likely to fail than a compression fitting.

 

[MasterAbacus]

Not to start on Ban again, but, what's wrong with through crimps and a bit of heatshrink?

READ THE OP...

He is short of space and cant get access for crimps etc.... Hence why he asked for info on soldering....

 

[Adam_151]

I'd be worried about making a solder joint in two solid conductors that carry quite a bit of power to be quite honest, I reckon the surface area of copper-copper contact is likely to be quite small, with the gaps filled with less conductive solder

With stranded conductors, you can intertwine the lengths for a bit, and then tightly wrap some bonding wire around the whole lot to force it together... mybe its just me, but the gut feeling is that two hooked together solid conductors, flattened and soldered would't be that good an electrical joint dispite having reasonably good mechanical strength

 

[emphasis303]

Thanks for all the replies guys espcially bas for the walk thru.

I am a bit concerned about what youve said adam, is there anyone who can clarify this? and to confirm, yes it is in a tight space.


One last thing is, with the heat shrink tubing, how do u heat the tubeing or what do you guys do when using a joint.

thanks once again

 

[ban-all-sheds]

Eutectic tin/lead solder has an electrical resistivity some ten times that of pure copper, but it's still quite low, and given the surface areas involved for contact, and the volume of solder, I don't think it'll be a problem.

FYI - 1 cm of a 2.5mm² conductor has a surface area of 56mm²....

 

[ban-all-sheds]

One last thing is, with the heat shrink tubing, how do u heat the tubeing

Hot-air gun.

or what do you guys do when using a joint.

Go outside.

 

[333rocky333]

Hot air attachment fitted on the same gas soldering iron.

 

[emphasis303]

lool @ bas

thanks yeh im not sure why that didnt come to mind using a hot air gun.

Cheers guys

 

[plugwash]

I find the easiest method to do heatshrink is with the side of your soldering iron bit. Just run it along the tubing and it shrinks nicely.

 

[saxondale]

dont bend it double and "hook... " it, lay them alongside each other or better still (though space is tight) wind one at right angles



strewth - spends all that time running the cable with minimum bend radiai then squashes it double