On 8/16/11 5:08 PM, AI4WM Bill wrote:
> If you can get a copper buss it may be better than aluminum; just my
> opinion. I never liked aluminum on the ground ( I hate it in electric
> panels too among other places) Jim's idea is good and sound and perhaps
> one of the easiest and it will be reliable.
>
> A properly crimped terminal will be nearly impervious if not impervious
> to water invasion and corrosion (only at the crimp). However correct
> crimping takes good tooling and the cheap tools that most people use
> will not really cut it. I did quite a few cross-sections when I worked
> for the largest connector corp in the world and I have seen what a good
> crimp can do and a poor crimp cannot do. Too bad the company does not
> exist as it did because they had tons of white papers and information
> available that is no more. Yes the areas around the crimp will need
> protected or they can corrode. Then crimp terminals have a problem
> outside also. Most are tin plated and there will be a problem with
> fretting, especially when joining to aluminum or stainless. There are
> gold plated, silver plated, and even platinum plated terminals available
> at very expensive prices.
>
The aluminum bus bar things actually have little ridges in the hole and
the sliding piece that clamps down (on the nice ones) to do the same
sort of gas tight seal thing that a good crimp does. They also have a
very fine pitch thread so that thermal effects don't loosen the screws.
After all, these things are designed to sit in a panel exposed to
daily and annual temperature fluctuations for 20 years without
significantly increasing the resistance. They probably use a carefully
chosen alloy of aluminum, too, relative to the CTE of copper.
(as far as crimps go, I am a huge fan of crimped connectors with the
proper tooling. I'll take a crimped SMA on semirigid over a soldered one
any day.)
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