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Old 25-May-2012, 9:23 PM   #8
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Join Date: Aug 2011
Location: USA Gulf South
Posts: 231
Originally Posted by xploremore View Post

Having said that, a ground connection using aluminum wire is a whole different thing. In most cases there is no noticeable load whatsoever. If there is, one would definitely have other things to worry about.

I use to install a lot of Starband satellites. The common practice back then was to install the ground wire using aluminum wire, which is what I did as well. However, after driving the ground rod into the soil, I always left a couple inches of the ground rod above ground. The aluminum wire was then attached (clamped) above grade. While this doesn't look quite as nice, it seems as if the integrity of the clamp is achieved by the connection being above ground.

Aluminum wire has many problems that make it a poor choice for ground wire. Aluminum was banned in the USA for home wiring. Unlike copper, aluminum oxidizes almost instantaneously when exposed to air. This is a good thing [sort of] because the aluminum oxide coating protects the wire from the elements. However, aluminum also develops small cracks when worked. This is a bad thing. Those cracks oxidize almost instantaneously. Cracks in metal propagate which explains some of the deep corrosion mentioned by GroundUrMast. Aluminum oxide is an insulator, which increases the effective gauge number of your ground wire which, in turn, reduces the wire's current-carrying capacity.

The bottomline is that aluminum represents an unnecessary risk as ground wire. Use copper.
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