> I agree that *I* wouldn't use aluminum,
>but Airstream didn't share those sentiments in the late '60's.

nor do all the power companies in the world... they use aluminum for their power distribution lines,
but they also use the proper installation procedures and equipment.

They would use copper, except it is so expensive people steal it causing unplanned outages. :-)

Its kind of amazing - aluminum used to be the most valuable metal in the world because it was so difficult to get out of its ore, but now it is so plentiful we make ladders, canoes and even trailers out of it :-) .... ain't technology wonderful.

> It doesn't necessarily "cause shorts", it causes hot connections due to oxidation and the
> physical movement during current applications. The movement causes connections to become
> loose, causing more heating, causing more movement, etc.

right.

the "physical movement during current applications" might need explained.

It is really a different expansion rate of the al wire and the wall plug connector because of heating at the connector.

It occurs because of an improper connection of al wire made to improper equipment eg- switches and wall plugs manufactured for use with copper wire only.

For example, Consider hooking wire up to a wall plug connector. During installation, the al wire is inserted under the screw, and the screw is tightened on it. The al is compressed under the connecting screw - ok so far, it works fine.

If a little loose, however, there is increased electrical resistance there, which heats that connection when power is applied - now with heating, al expands faster than the rest of the connection. Since al is softer, it gets flattened a little during expansion, and voila - a bigger gap when it cools down --> its looser, which means greater resistance the next time power is applied.

Another factor is the aluminum oxide on the wire, which occurs more readily when the al is heated,
and it has a higher resistance than the al itself. Thats why standard practice with aluminum wiring
is to use an anti-oxide grease if air can get at the connection.

> You then get a fire. :-(

not usually, although it can happen.

what usually happens is, after a great number of power cycles where the connection is getting worse and worse, you get annoying flickering on whatever is downstream from the bad connection eg - the light start flickering.

The connection gap eventually gets big enough that no electricity flows and you have to get the connection fixed to make it work.

another problem is bad installation procedures, where the ignorant electrician bends the al wiring a lot during installation. Al does not endure as much of this as copper does, so you can get a high resistance in the wire itself  due to this work hardening process, which means it fails sooner.

Also, some wall plugs have these little holes in the back for the wires. These are used instead of the screw connections to save time and labor costs. Aluminum does poorly with this type of connection.
Copper fails too - it just takes longer.

most recent building codes recognize the futility of expecting the lowest bidder to employ competent electricians and to use the proper connections, so the coders take the easy way out and ban the aluminum for this use.

if you have al wire in your trailer what do you do?

Regularly make sure the connections are tight.

You might want to go to the electrical supply and get some anti-oxidation grease and squirt it into the connection before tightening.

Some experts recommend installing special crimp-on pigtails at every wire connections, and some experts recommend you do not. :-/ These kits are available at electrician supply stores.

if you are determined to handle it yourself, be aware of the hazards and responsibilities - you are responsible! not me, not the guy next door.

Try to get an electrician familiar with al wire.

unfortunately if a "qualified" electrician screws up your problems will still occur, but the insurance companies are happier.

MORAL:
if you do not know what you are doing, don't do it. Or use copper wire - it is more forgiving of mistakes.

Or if you have lots of money, use silver , it is an even better conductor than copper :-)

good luck
darrell