Al Cables instead of Copper

We are trying to convince our design team about the use of Aluminium cables in underground electrical design (they have been allowing only copper so far which is 3-4 times more expensive). To back this recommendation we need to find credible examples of landmark buildings form developed countries

Does anyone know of landmark buildings, like airport, hospitals etc. in N america or Europe that have used Al cabling ?



asked 6/24/2012

3 Answers

I suggest aluminium cables for larger size supply cables both outside and inside buildings and smaller size copper cables for sub circuit wiring from consumer unit or load centre to lights,sockets etc where one come across bends,twists and terminations.

answered 6/27/2012 naban 6

I would prefer to use copper, inside buildings, it is not only the cost of the cable, it is its size and  the cable conduit, for example a THW cable  ( Without derating, 30ºC ):

A Copper Wire, THW, size #8 have a   permissible current capacity of 50 Amp.    

Aluminium Wire THW, size #8 have a  permissible current capacity of 40 Amp.

So for 50 Amp you would need a #6 THW AL conductor, so all the installation would be bigger.

So for a building I would use Copper, also it is wisely to be sure depending in which country are you working that the contractors have enough experience with that type of materials, and knowledge of the appropriate tools and hardware required for that job. 

For example, in Latin America some country's have several importation problems so waiting for non-standard hardware and tools would delay the project. So what you think is cheap would cost more at the end with unpredictable results due to the lack of experience of the contractors.

Hope that someone with more experience using AL wires gives us a good example an a real life example using AL wires. I would like to improve my knowledge in AL cables for this type of installations. 

answered 6/25/2012 LuCG 12
Most of the buildings I have seen use copper (but I don’t think people really do any cost analysis). I have done some medium voltage distribution projects for Vector [main Auckland lines company] New Zealand and they do use aluminum.

Not cables, but you probably get a few of the same arguments – I have argued for aluminum in dry type transformers. To my knowledge Siemens standard Geafoil transformers are standard with aluminum. If your using aluminum in your transformers, then why not in the cables.

For aluminum, besides cost, there are a few issues to be aware: bi-metallic connections, different type of crimping required, cracking if bent too much or subject to lots of vibration and installation costs may be higher.

Sorry can’t be more help. Maybe other people will have more experience.
answered 6/25/2012 Steven McFadyen 246
Steven McFadyen

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