Aluminum Wiring
Due
to implications in numerous house fires, the once
common practice of using aluminum wiring during the
1970's is no longer permitted in new installations
in most jurisdictions. If your house has aluminum
wiring you do not necessarily need to panic.
Aluminum wiring can be just as safe as copper wire
as long as it has been installed correctly. The
concern with aluminum wiring is that it is very
unforgiving if it has been installed incorrectly.
Aluminum wiring expands when it warms up, and
contracts then it cools down. Aluminum reacts
differently than copper wire after several
warm/cooling cycles. After each cycle aluminum tends
to lose more of its tightness. This process is often
referred to as "cold creep". Combined with
aluminum's tendency to oxidize when in contact with
certain metals, these factors can lead to dangerous
problems. When aluminum oxidizes it heats up more to
conduct the same amount of electricity, which then
causes more oxidation. Due to this cycle, eventually
the wires may start to get very hot, melt the
fixture that it attached to, and even possibly cause
a fire.
If you are considering purchasing a home with
aluminum wiring, or have discovered it later, it
would be a good idea to hire a licensed electrician
or inspector to check over the wiring for any
potential problems.