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Aluminum Electrical Wiring Hazard:
 | Aluminum wiring, used in some homes from the mid 1960's to the early
1970's, is a potential fire hazard. |
How safe is aluminum wiring?
| According to the U.S. Consumer Product Safety Commission, fires
and even deaths have been reported to have been caused
by this hazard. Problems due to expansion, or more likely micro-fretting
and arcing at the connectors, can cause overheating
at connections between the wire and devices (switches and outlets) or at
splices. The connections can become hot enough to
start a fire without ever tripping a circuit breaker!
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| CPSC research shows that "homes wired with aluminum wire manufactured
before 1972 are 55 times more likely to have one
or more connections reach "Fire Hazard Conditions" than are homes wired
with copper. "Post 1972" aluminum wire is also a
concern. Introduction of the aluminum wire "alloys" in 1972 time frame did
not solve most of the connection failure problems.
Aluminum wiring is still permitted and used for certain applications,
including residential service entrance wiring and single-purpose
higher amperage circuits such as 240V air conditioning or electric range
circuits. The fire risk from single purpose circuits is
much less than for branch circuits. But it's not necessarily because of a
"new alloy" as some folks assert. It's because there
are enormously fewer connections (four or six rather than 30 or 40 per
circuit) and thus statistically a smaller chance of a
connection failure. These connections do still burn up, as indicated by
field reports. |
Reducing the Fire Hazard in Aluminum-Wired Homes:
ANY REPAIRS MUST BE DONE BY A QUALIFIED ELECTRICIAN:
| Aluminum-wired connections in homes have been found to have a very
high probability of overheating compared with copper-wired connections.]
The aluminum-wired connections that fail tend to progressively deteriorate
at a slow rate, and after many years can reach very high temperature
while still remaining electrically functional in the circuits. A large
number of connection burnouts have occurred in aluminum-wired homes. Many
fires have resulted, some involving injury and death.
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| The probability of aluminum-wired connection overheating in a home
varies considerably according to the types of connections, the
installation
methods used, and the circuit usage, along with many other factors.
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| The most certain corrective action for all cases would be to rewire
the home with copper wire. This is expensive and impractical in most
cases.
A practical approximation to rewiring can be achieved by a method known as
"pig-tailing", using a specially-selected connector and installation
method to splice a short length of solid copper wire to each aluminum wire
end. The copper wire "pigtail" is then connected to the circuit breaker,
light fixture, receptacle, dishwasher, or other termination. This method
is only effective if the connections between the aluminum wires and the
copper pigtails are extremely reliable. Pig-tailing with some types of
connectors, even though they might be presently listed by UL or certified
by
CSA for the application, can lead to increasing the hazard.
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| Other actions and partial repairs are less certain in effectiveness,
but they still can substantially reduce the risk of fire due to aluminum
wire
connection overheating. Among the possibilities are replacing certain
failure-prone types of devices and connections with others more compatible
with the aluminum wire, and removing the ignitable materials from the
vicinity of the connections. These actions can be accomplished at lower
cost than rewiring or complete pig-tailing, but with less reduction of the
hazard. The homeowner has choices to make.
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Note:
The Information contained within this website is for informational
purposes only. Kevin M. Leonard & The Home Inspection Company always
recommends that a qualified expert be consulted in the area of concern
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