EE people: Why use aluminum wiring?

[Rakehellion]

Isn't copper better for pretty much everything?

 

[ControlD]

Isn't copper better for pretty much everything?

Except for cost.

 

[brianmanahan]

i predict this thread will be 1000 pages long

 

[Homerboy]

Google is a bitch!

http://www.doityourself.com/stry/copper-vs-aluminum-wiring-which-to-use#b
http://electrical-engineering-portal.com/copper-or-aluminium

 

[Matthiasa]

It is also weighs less for a given resistance among other things.
Although that is not all that important for home use.

 

[DrPizza]

Isn't copper better for pretty much everything?

What do you mean by "better for pretty much everything?" For carrying a certain amount of current, you need a bit larger of a cross sectional area; but cost-wise, for identical current carrying capacities, aluminum has copper beaten by a mile. Issue two is aluminum oxide - and that's fairly easily circumvented. (There are other termination issues related to the tendency of aluminum to build up a coat of aluminum oxide, but these problems are pretty much eliminated with proper terminations & worksmanship. Creep used to be a problem, but, as far as I'm aware, that's not really an issue any more, assuming good materials.)

 

[Rakehellion]

What do you mean by "better for pretty much everything?" For carrying a certain amount of current, you need a bit larger of a cross sectional area; but cost-wise, for identical current carrying capacities, aluminum has copper beaten by a mile. Issue two is aluminum oxide - and that's fairly easily circumvented. (There are other termination issues related to the tendency of aluminum to build up a coat of aluminum oxide, but these problems are pretty much eliminated with proper terminations & worksmanship. Creep used to be a problem, but, as far as I'm aware, that's not really an issue any more, assuming good materials.)

So copper is better, it's just that aluminum is cheaper.

 

[William Gaatjes]

And weight. I think tensile strength also has something to do with it. There are many different types of aluminum.

 

[Scarpozzi]

Cost. In the past 4 years, I've run about 450 feet of aluminum cable for less than $450.

I was quoted $600 for 100 feet of copper on the last job I did (because it was indoors and copper IS preferred. I decided it wasn't worth the extra money considering the new aluminum cable is wrapped/insulated for indoor use and approved for attics and crawlspaces. You just have to pain the exposed leads to prevent oxidation.

(the other 350' was outdoors for a boathouse and was mobile home feed, direct bury....I was happy to bury aluminum rather than burying copper cable at the higher price)

 

[master_shake_]

my first house was aluminium.

in the 70's when it was built copper was too expensive.

aluminium is just fine and will pass any house inspection because at the time it was code.

if you renovate then you must change it to copper.

 

[William Gaatjes]

When it comes to high voltage power lines :

https://en.wikipedia.org/wiki/Overhead_power_line#Conductors

The most common conductor in use for transmission today is aluminum conductor steel reinforced (ACSR). Also seeing much use is all-aluminum-alloy conductor (AAAC). Aluminum is used because it has about half the weight of a comparable resistance copper cable (though larger diameter due to lower specific conductivity), as well as being cheaper.[1] Copper was more popular in the past and is still in use, especially at lower voltages and for grounding. Bare copper conductors are light green.

This is an interesting read.

https://en.wikipedia.org/wiki/ACCC_conductor

 

[edro]

I thought the skin effect also had something to do with aluminum being used instead of copper on high voltage transmission.

 

[William Gaatjes]

I thought the skin effect also had something to do with aluminum being used instead of copper on high voltage transmission.

Skin effect depends on the frequency of the alternating current. at 50 or 60Hz it penetrates deep enough. But if i am not mistaken even at those low frequencies, a solid core does not give a benefit versus a hollow core. There is a formula for to calculate the penetration depth.


edit:

If i can believe wiki :

At 60 Hz in copper, the skin depth is about 8.5 mm.

 

[edro]

Hm, maybe I am thinking multi conductor versus solid conductor...

 

[William Gaatjes]

Interesting.
I was wondering what the diameter was of high voltage power line wire.
This cable has multiple sub cores and is available in a total diameter of 28.1mm.
The core in the middle is to increase the tensile strength of the wire.

 

[William Gaatjes]

Hm, maybe I am thinking multi conductor versus solid conductor...

Well, it is true that when you have to make for example a high power switch mode power supply (smps) transformer which is used at a frequency of (for example) higher then 50 KHz, it is better to use litze woven wire instead of a solid core wire. But that is because of the skin effect. Since the current only penetrates the conductor for a given depth, you can better use multiple tiny cores woven together. Then the total current capacity of the wire is increased. But that has to do with the current not the voltage.

edit :

https://en.wikipedia.org/wiki/Litz_wire

 

[Iron Woode]

my first house was aluminium.

in the 70's when it was built copper was too expensive.

aluminium is just fine and will pass any house inspection because at the time it was code.

if you renovate then you must change it to copper.

house insurance companies don't like aluminum wiring here.

Ontario Hydro recommended removing it and running copper instead.

Its next to impossible to find co-al compliant electrical devices like receptacles and switches.

My last house had aluminum wiring. yuck.

 

[pauldun170]

http://www.cpsc.gov//PageFiles/118856/516.pdf
http://www.nytimes.com/2006/02/19/realestate/19home.html?_r=0

Around here aluminum wiring is typically old installs and ready for chucking.
I'm looking forward to the day when I get rid of the last of the old aluminum wiring in my house.

 

[BurnItDwn]

Aluminum sounds cooler when said in a sentence.

 

[master_shake_]

house insurance companies don't like aluminum wiring here.

Ontario Hydro recommended removing it and running copper instead.

Its next to impossible to find co-al compliant electrical devices like receptacles and switches.

My last house had aluminum wiring. yuck.

my insurance only asked if knob and tube.

 

[Aharami]

http://www.cpsc.gov//PageFiles/118856/516.pdf
http://www.nytimes.com/2006/02/19/realestate/19home.html?_r=0

Around here aluminum wiring is typically old installs and ready for chucking.
I'm looking forward to the day when I get rid of the last of the old aluminum wiring in my house.

this thread piqued my interest because I am going through a whole house reno process and I am redoing all the electrical wiring in the house. Not knowing anything about AL wiring, the fact that it is much cheaper got my attention. But thanks to your links, I'll be sticking with copper

 

[TheSiege]

Aluminum also expands and contracts with heat causing connections to come loose more easily, the main reason its not used as widely as copper.

 

[LTC8K6]

Aluminum wiring is widely used in modern airliners for weight savings, so they must have conquered the problems.

Lots of stuff from China has what appears to be copper coated aluminum wiring. It appears to have copper wiring, but closer inspection shows that it's not copper.