How much are Aluminium cables used in your country?. I had the task of connecting a 300mm2 3core+ Neutral with XLPE insulation, recently, at a Meat-works. To say the least, it was a real job in itself, just to crimp the lugs onto the ends of the wires, these are filled with grease, to assist the crimp. But, can anyone please tell me, if there is a manufactured form of acid or some other chemical, that will remove the oxide layer from the Al, before the crimp is made?, as these wires are going to be carrying 400-600A, I would like to think that the oxide layer, has some resistance(electrically). Any help on this, would be cool.
I know AL is used in line work and some heavy industrial cabling, but that's a little out of my league, so I can't be more specific.
In normal residential work, aluminum never caught on as it did at one period in the States. Pre-metric cables were tinned copper rather than just bare copper, which sometimes leads people to believe that they have Al cables.
In the UK aluminium cables are not permitted below 16sq mm. In my area only the PoCo use Al cables. They installed a 100A 3 phase PME (MEN) service on a job of mine this week. The cable was 35mm Al 3 core concentric (neutral screened cable), the concentric screen is Cu.
Re: Aluminium Cables#134794 12/02/0201:00 AM12/02/0201:00 AM
Thanks for your replies, guys, Aluminium is only used over here, where CU becomes un-economical. For Underground work, anything larger than 70-95mm2, will be laid in Al, as opposed to Copper. All of our Overhead Lines that carry more than 400V, are run in Aluminium, with a Steel core, for mechanical strength. CT-Wireman, what type of Anti-Oxidant is the most used in the US?.
Re: Aluminium Cables#134795 12/02/0211:14 AM12/02/0211:14 AM
Paul, I was told by a migrant Electrician, from the UK, that Aluminium, was used for the internal wiring of houses, in the 60's, just like NM or TPS, except it had a stranded??, aluminium core, that was larger than the Copper equivalent. This was a real nuisance as far as terminating wires into a ceiling rose was concerned(as far as I was told), as I guess they were only 5A types, back then. Could you or David please expand on this?.
Re: Aluminium Cables#134797 12/22/0207:33 AM12/22/0207:33 AM
I've never heard of aluminum cables used in normal domestic branch circuit wiring here. As David mentioned, the IEE Regs. prohibit the use of smaller AL cables and have done so for a long time.
The metric-size cables introduced in 1970 are solid copper in all sizes up to 2.5 sq. mm.
Prior to that, we did use stranded cable much more often. The ring circuit was generally wired in a type known as 7/.029, for example (i.e. 7 strands, each .029" diameter). Although at first glance this wire might look like aluminum, it is in fact tinned copper strands.
Under this old system the only non-stranded cable in use was 1/.044, a very small size limited almost exclusively to domestic 5A lighting circuits. But even this was tinned copper, and therefore had a silver appearance.
Like I have said before, I have never seen Al conductors of small cross section in domestic wiring. There used to be a reference to copper clad aluminium conductors in an older edition of the wiring regs. I think they may have been used during a copper shortage in the early 70's. I have seen a Cu clad Al conductor once only in my 20 years in the trade. It was used as a main earth bonding conductor to the water service in a house rewired around 1970, this cable was sized 10mm at a time when 6mm Cu would have been the norm.
Re: Aluminium Cables#134799 12/23/0207:00 AM12/23/0207:00 AM
Some abandoned 1950ies wiring in our new bathroom was 1 mm2 PVC sheathed aluminum. (Single balck wires in plaster, we found it when taking down the tiles) This was the only occasion I've ever seen aluminum wiring.