Aluminum Wiring
By
Frank Ross
In
the late 1960's and early 1970's copper prices rose and
contractors/electricians switched from copper to lower costing
aluminum wiring. Although no longer common for distribution
circuits, aluminum wiring is still used today in certain
applications. For example, 240 volt circuits for stoves and dryers.
It sometimes is used on the main service entrance wire from the road
to the house.
Concerns with this type of wiring have arisen, for example, when
aluminum wire is connected to devices (e.g. receptacles, light
fixtures) which were not designed for aluminum, or, when aluminum
and copper wires are attached. In these cases a reaction can occur
causing the connections to fail, perhaps become disconnected,
and/or, potentially overheat, spark and catch fire. Symptoms of this
can sometimes be seen in the discoloration of receptacles,
flickering lights, or the smell of hot plastic insulation.
The
conductivity of aluminum is not as good as copper so a different,
thicker, gauge wire must used. For example, today the most common
copper wire size is 14 gauge. The comparable aluminum wire size used
was 12 gauge.
What
do you do if you suspect a problem? Have a qualified electrician
check:
1)
Terminations at devices without removing or disturbing them.
2)
Cut back any damaged aluminum conductors and join these to a copper
tail using a connector approved for use with aluminum. These
connectors are colored either brown or purple, depending on the
manufacturer. The copper tail is then terminated at the terminal
screws of an ordinary device (which includes approved receptacles,
etc.). Or, cut back any damaged aluminum conductors and re-terminate
at a new device bearing the appropriate marking. Only devices
bearing the mark CO/ALR are currently approved for use with aluminum
wiring.
3)
Panel board terminations for signs of overheating.
4)
Fuses present for heavy loads are temperature sensitive type (D or
P).
If a
home has aluminum wiring and you suspect problems may exist further
professional advice from a qualified electrician, experienced in
repairing aluminum wiring concerns, is recommended.
Frank Ross is a Certified Utah Home Inspector for Pillar to Post
Professional Home Inspection and a full member of the National
Association of Certified Home Inspectors. Readers may contact Mr.
Ross at (435) 867-6400 or
frank.ross@pillartopost.com. You can learn more about Pillar To
Post Professional Home Inspection at
www.pillarposthomeinspection.com
