Re: [A/S] Serious discovery!

["Dr. Gerald N. Johnson, electrical engineer" <geraldj@xxxxxxxx>]

I've considered that the looseness of single strand aluminum wires comes
from the differential expansion between the wire and the brass screw. As
the wire heats, aluminum expands more than brass but since the brass
screw retains it the aluminum has to spread at right angles to the screw
pressure. Then when the assembly cools the aluminum shrinks in all
directions and the screw is loose. Next time there's a load it heats a
lot faster and repeats the deformation. All together a bad idea, "bad
scene", fires and shocks including deaths result when the ground wire
looses its connection. Been there, done that as an expert witness. Had
to explain deaths to parents.

Pigtails with ratcheted crimp tools are one way to solve the problem.
There are also receptacles and switches rated for connecting to aluminum
wires. Look for Al/Cu near the connections. Many are rated only for
copper (Cu) and are very bad with aluminum. The aluminum connection
greases can't hurt because they contain zinc crystals in the grease to
break through the aluminum oxide inherent on any aluminum exposed to air
and the grease keeps the aluminum from being exposed to air. But the
grease alone is not good enough with receptacles and switches not rated
for aluminum.

Rewiring with copper is the optimal solution for safety. Replacing the
wiring devices with those rated for aluminum is a big step towards
safety. Pigtails are a big step towards safety. 

So long as you have aluminum wiring, the receptacle AND the main panel
need attention to those connections and the breakers need to have lugs
rated for Al/Cu, you may wish to avoid using electric heaters, vacuum
cleaners, cookers, and toasters on those circuits. Wire heating is worse
with large loads, insignificant with razors, and clock radios.

Don't accept any receptacles or switches not rated for aluminum wire. If
they aren't labeled specifically for use with aluminum wire they are
hazardous with aluminum wire. Part of the problem in the 60s was that
there weren't such labels or products. They may be hard to find now
since most of the structures built that way have already burned to the
ground drastically reducing the market.

I don't find any parts in my several year old WESCO supply catalog that
are labeled specifically for Al/Cu but I have seen such products.

Be careful with wiring, hire a qualified electrician if you have any
questions. Cousin "George", the electronics technician, isn't qualified.
Death from electrocution or fire is permanent but not necessarily
instantaneous.

Gerald J...