Aluminium SWA Cable

Marvo · Jun 6, 2011

We regularly install control panels and the supply is an SWA cable. We obviously install the cable and lug it onto the main breaker and neutral bar. We are building a pump control panel at the moment and are due to install next week so I went to site today for the final survey.

One thing I noticed by chance is that the SWA supply cable has solid aluminium conductors and armour. It's the first time I've encountered a cable of this construction and we don't stock suitable aluminium lugs for terminating.

I spoke to our two main electrical suppliers and have sourced the lugs but neither supplier could tell me what type of crimping tool would be necessary. These lugs are very long compared to the usual lugs for the copper cable and they're a triangular cross-section to match the cross-section of the solid aluminium cores in the cable. The control panel is fairly light duty (<150A 3-phase) but none the less I'm not keen on using our standard hexagonal shaped crimper, I'm thinking the distortion it will cause to the conductor and lug may result in higher temperatures at the connection.

Any pointers in the right direction would be appreciated.

Knobhead · Jun 7, 2011

If you use the crimping tool, bear in mind what I said about over crimping.
You will have to do several crimps over the length of the lug.

The lugs should be supplied in a sealed bag with the anti-oxidant pre coated, wire brush the core first and then fit the lug with the coating still inside.

pennywise · Jun 7, 2011

You could use mechanical lugs, these are in sector profile and are suitable for solid Aluminium conductors.No crimper required just brute force and a socket set.

http://www.etscc.co.uk/jkcm/plugins/ProductsInCategory.aspx?cat=3099

benji · Jun 7, 2011

Aluminium was used a lot in the 1960s due to copper shortage there was a different nest/anvil for 2c ,3c & 4c but the same indent mostly a single indent but larger sizes had 2/3 indents, soldering sounds difficult but with care it,s just the same as copper correct solder&flux and be carefull with the heat

Marvo · Jun 7, 2011

Okay, I've found a candidate locally that looks like it will do the job. It's the 'BOWCRIMPT' model on the page linked. It's nothing to write home about quality-wise but I'm guessing/hoping it won't be too expensive being a manual crimper and the info says it can go up to 120mm² which is one size up from the cable I'm dealing with.

I like the look of the mechanical bolt-on lugs Pennywise, they would certainly make life easy for a one-off job but I would probably have to order them from the UK because I very much doubt they're available here unfortunately.

I have one other question for the aluminium cable whizzes here, being a solid core conductor cable, is the bending radius of the cable and also the individual cores significantly wider than the equivalent sized copper cable?

Thanks to all who have helped, it's greatly appreciated.

pennywise · Jun 7, 2011

They are pretty good crimpers, a very widely copied design that'll never go wrong. you can pick them up for around £115 over here. Is it that bad in SA for parts and tools? does stuff just get nicked alot!

Marvo · Jun 7, 2011

Oh yeah, stuff does get nicked if you're not careful but it's possibly not as bad as it is in the UK though; some of the posts I've read on this forum have been a bit of an eye-opener. We don't get thoroughbred pikeys here, just your common or garden low-lifes.

Tools and electrical supplies are readily available, until you need something that's slightly off the beaten track, that's when I end up sourcing stuff from overseas. Luckily I have good contacts in the UK, US and a few other places but the cost sky-rockets with shipping, import duty etc etc. I'll find out how much the crimpers cost tomorrow and let you know.

Knobhead · Jun 8, 2011

Re: bending solid cores. They will take the same bend as any other cable, but, and it’s a big but, don’t bend the core to many times as aluminium work hardens and starts to crack. Do it once and make sure you get it right. Just a quick tip, you will find the lug grows in length as you crimp it. Not so bad with a 95mm, start playing with 930mm and it can start causing problems. The last transformer I did the guys with me thought I was mad cutting the cable ½” short. Once crimped all the boltholes lined up perfectly.

The crimpers look a good bit of kit.

I like working with aluminium but I’ve been doing it for a long time.

As for soldering, unless you’ve got a temperature controlled metal pot and can do flow soldering don’t even think about it. I’ve only done it with AL paper lead cables where burning the insulation isn’t such a problem.