How to join thick electrical wire ?

whipper_snapper

whipper_snapper

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Any suggestions on the best way to splice together lengths of thick electrical wire. I always try to avoid having to do this all, but sometimes there is no choice. For thin stuff I always twist, solder, cover with adhesive lined heat-shrink, provide mechanical support.

However, now I have to splice thick cable to the tails from the windcharger. Twisting and soldering is a mess and I a completely unconvinced by th quality of the result even after using a mini blowtorch to get it really hot. Plan B is to crimp and solder big lugs and bolt them together. But I don't have a crimp tool that will handle such big lugs so I would have to just nip them closed with mole grips or similar and rely heavily on the solder. Any better ideas ?

Thanks
 
Armoured cable splice kits use uninsulated single screw terminal block connectors which are then encapsulated in a potting compound (epoxy?). If you can hide the connections you could use something similar.
Alternatively there is a range of 2 pin heavy duty plugs/sockets that are used for jump leads etc. called Anderson Plugs, look on Ebay.
 
I used to do this with battery cables.

Un-twist the strands, fan out, slide the ends (strands) together, overlapping each of the strands so they intermingle, roll this area (splice) in your hands (fingers) now solder the strands all together on masse. slide heatshrink, glue lined sleeving over the join, on the soldered bit only, then slide more glue lined heatshrink over the whole of the area an seal the whole lot. Works fine and no resistance join.

Hope this makes sense!
 
I've had to do this many times in BDR (Battle Damage Recovery) exercises on very heavy 28v DC cables. If you can get the tube connectors Tinkickers method is great. As he says, make absolutely sure the wire is butting up to the end of the tube. If it's very thick cable you have to shape the ends a bit. Don't worry too much about the crimping with them - it's usually the solder that makes the electrical connection and the crimp does the physical support. The solder should fill the tubes completely so make sure you get the size and that the wires fit properly.

Englander's method is taught in the RAF too. Couple of points - get the best flux you can and make sure the surfaces to be joined are spotless - no grease oxidation or anything. Once you've cleaned them don't touch with your bare hands. Apart from contaminating the surfaces again you'll probably get a strand stuck in your skin and that can be a *!%£)!! moment.

The only bit of the metal that needs to be hot is the bit that's touching the solder - technically even that doesn't if you could the solder hot enough. I wouldn't bother with a blow torch - either use the biggest electrical iron you've got and just do a little bit at a time or try and get a plumber's soldering iron - one of the things that looks like a poker with a square bit on the end. You an use the blow torch to get that glowing hot and that'll do the trick.

Final point - you've created a hard point in the cable. If it goes anywhere near the engine or is subject to any significant vibration then make sure the cable is supported at 2 or 3 points either of the join. After you put the heat shrink on (use the stuff with adhesive in) then you an also wrap tape around the join, making it gradually thicker as it approaches the join. This reduces the effect of the the single stress pint where the solder ends and the cable starts flexing.

Finally - don''t forget to put the heat shrink on first /forums/images/graemlins/blush.gif

G
 
Thanks all, very helpful.

I did try interlocking the strands and soldering but could not get it to work well, I am probably too ham fisted and I was working in an awkward and greasy place.

I have tried googling for tube connectors without success, any suggestions for sources ? The wire I am adding is 8AWG and the existing tails are thinner - I guess 10AWG.

One additional challenge is that I need to common the 'ground' and the neg cables. Is there any kind of 'double tube connector' which allows 2 wires in and 1 out with everything commoned?

Thanks
 
R.S do have cable splices for wire sizes uo to 10.5 mm2

Your 10AWG is 5.27 and your 8AWG is 8.35

size conversion

I would have thought most electrical suppliers would have then. The normal yellow plastic covered crimps go up to 6.5mm2
 
[ QUOTE ]
One additional challenge is that I need to common the 'ground' and the neg cables. Is there any kind of 'double tube connector' which allows 2 wires in and 1 out with everything commoned?

Thanks

[/ QUOTE ]

clicky
 
I would shy away from soldering as this is effectively creating a solid core cable where vibration will crack the soldered joint creating high resistance.

I would recommend using a butt joint crimp...

p34_ButtSplice.jpg


as a good mechanical joint is always a good electrical joint. Then finish with self-amalgamating or heat shrink.
 
Because he was having problems with soldering, in that for battery cables you need a large flat iron, which not many people (inc me) do not own. So I found him some solutions to the two problems he asked about. It seems he does not require them anymore so I may have well not bothered. /forums/images/graemlins/frown.gif
 
Sorry if you feel ignored, I issued 2 general thanks for all of these useful responses.

I have ordered butt splices as you and others recommended, not from the supplier you recommended as they did not stock the sizes I needed.

The commoning system you suggested would not work as it will be dangling inside the support pole. But since the in wires are thinner than the out wires I have sized the splice to allow 2 wires in and one wire out.

I will solder with a mini butane torch and provide mechanical support.
 
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