I didn't see your previous post, but if you are joining two dissimilar
metals, be sure to use a joint compound to prevent moisture from touching
the connection. If you were to join copper to aluminum with no means of
preventing moisture from bridging the joint, corrosion loss will occur over
time. This is the accelerated corrosion (loss) of the least noble metal
(anode) while protecting the more noble (cathode) metal. Copper, in this
example, is the more noble metal.

The aluminum will pit to the copper leaving less surface area for contact.
The connection could be become loose, noisy, and even allow arcing. These
corrosion problems can be prevented by using a joint compound, covering and
prevent the bridging of moisture between the metals. The most popular
compounds use either zinc oxide or copper particles embedded in silicone
grease. As the joint pressure is increased, the embedded particles dig into
the metals and form a virgin low resistance junction void of air and its
moisture. My electricians use nolox, but I'm sure there are other brands
out there that work just as well.

just my .02
S.


"Harry Muscle" wrote in message
oups.com...
Thanks to everyone who's responded to my last question about aluminum
wiring. I thought I'd investigate the option of using a hydrolic
pressing or crimping tool to add copper pigtails onto the aluminum
wires. Apparently that's how aluminum wire connections are made by the
utility companies.

I know there's a tool available and certified for residental wiring,
called COPALUM, unfortunately the company who offers this tool has very
strict rules and regulations, etc. regarding who can use it, etc. ...
making it quite expensive to actually use, not to mention that no one
in Canada is actually certified at the moment to use this tool.

However, electrical utilities obvioulsy have tools that they use also
for such things. Hence I'm wondering if anyone could help me dig up
some information on other powered crimping tools that can be used to
attach copper to aluminum wire.

Thanks,
Harry