Aluminum wiring was
used in the 1970's for the wiring of receptacles
and switches. Single stranded branch aluminum wiring,
has been implicated with fires in houses. Aluminum
does not conduct electricity as efficiently as copper
and creates more resistance and heat. The wire expands
and contracts more than copper. The problem was compounded
by screw heads which were too small at the devices.
This expanding and contracting are susceptible to
working the connections loose at the receptacles
and switches. This is where a short can occur as
oxidation builds up between the aluminum wires, and
pose a potential fire hazard. Updated devices with
larger screws were created however, these are not
considered the best or only solution. Some people
feel the aluminum should be removed and copper replaced.
There are some approved and accepted methods. Standard
wire nuts are not approved for pig tailing and according
to the Consumer Product Safety Commission may be
a greater fire hazard and should be repaired.
Approved Methods According to the Consumer Product
Safety Commission include:
- Copper pig-tails crimped onto the aluminum
at all receptacles and switches. A special tool
is used for this application.
- UL. approved wire nut connectors, filled with
anti-oxidant cream, designed specifically for
aluminum to copper connections.
- Secure connections as is on approved Al/Cu
devices.
- Use antioxidant on all aluminum wiring connections
Monitor conditions such as flickering lights,
voltage drop, or warm receptacles. In any case,
an electrician familiar with aluminum wiring should
be consulted to verify proper connections. Multi
stranded aluminum wiring is not part of this problem
and of no concern. The majority of modern 220 amp
rated houses are utilizing multi stranded aluminum
wiring. COPPER CLAD ALUMINUM Copper Clad Aluminum is easily mistaken for copper.
It does not have the same problem with oxidation
build up as does aluminum. It is typically a #
12 wire and still needs proper devices with the
larger screw heads or approved pig tailing methods.
To identify Copper Clad Aluminum look for a silver
color at the ends of the wires where they are connected
to the grounding bar. Another location to identify
Copper Clad Aluminum is in the attic or crawlspace.
In these areas look for the identification on the
wire sheathing such as CU Clad AL. |
