On
April, 28, 1974, two persons died in a home fire in
Hampton Bays, New York. Fire officials determined that
the fire was caused by a faulty aluminum wire connection
at an outlet.
Since that tragic
accident, the
U. S. Consumer Product Safety Commission
staff and other government officials have investigated
numerous complaints from homeowners throughout the
nation who have had trouble with small gauge aluminum
branch circuit wiring. The Commission has also had
research conducted that shows that homes wired with
aluminum wire manufactured before 1972 (“old technology”
aluminum wire) are 55 times more likely to have one or
more connections reach “Fire Hazard Conditions”** than
is a home wired with copper.
**The survey conducted by the Franklin
Research Institute defined “Fire Hazard Conditions”
to occur when receptacle cover plate mounting screws
reached 149 degrees C (300 degrees F), or sparks were
emitted from the receptacle, or materials around the
receptacle were charred.
The hazard investigated by the Commission
staff occurs at connections to old technology aluminum
wire, such as at outlets or switches or at major
appliances such as dishwashers, furnaces, etc.
Corrosion of the metals in the connection, particularly
the aluminum wire itself, causes increased resistance to
the flow of electric current and that resistance causes
overheating.
Homes built before 1965 are unlikely to
have aluminum branch circuit wiring. Homes built,
rooms added, and circuits rewired or added between 1965
and 1973 may contain aluminum wiring.
In 1972,
manufacturers modified both aluminum wire and switches
and outlets to improve the performance of aluminum wired
connections. Sale of the old style wire, switches and
outlets still on dealer’s shelves however, continued
after 1972.
Trouble Signs
Signs of trouble in
aluminum wire systems include:
Unfortunately, not all failing aluminum
wired connections provide such easily detected warning
signs; aluminum wired connections have been reported to
fail without any prior indications or problems.
What the Homeowner Can Do
If you
have noticed any of the trouble signs, have a qualified
electrician determine whether the problem is caused by
deteriorating connections to aluminum wiring. DO NOT
TRY TO DO IT YOURSELF.
You could be electrocuted or you could make the
connections worse by disturbing them. If you are not
certain whether your home has aluminum branch circuit
wiring, you may be able to tell by looking at the
markings on the surface of the electric cables which are
visible in unfinished basements, attics or garages.
Aluminum wiring will have “AL”
or “ALUMINUM” marked every few feet along the length of
the cable. (Note - the marking “CU-CLAD” or
“COPPER-CLAD” in addition to the “AL” or “ALUMINUM”
means that the cable uses copper-coated aluminum wire
and is not covered by this message.)
If you do have aluminum branch circuit
wiring, the Commission suggests that you have a
qualified electrician check the system for impending
trouble. Remember, you may not have noticed any of the
warning signs, but research shows that trouble may
develop over time and an electrician may spot potential
problems before you notice them.
Can the Problem be Fixed?
One method of eliminating the risks
associated with old technology aluminum wiring
terminations is to eliminate the primary cause: the
aluminum wire itself. Depending upon the architectural
style of your home and the number and locations of
unfinished spaces (e.g., basements and attics), it may
be relatively easy to rewire your home. A new copper
wire branch circuit system would be installed, and the
existing aluminum wire would be abandoned inside the
walls. This is the most expensive method of repairing
an aluminum wired home; but if you can afford the cost,
it is also the best method available.
Since it may be impractical to rewire
some types of aluminum wired homes (e.g., condominium
units), or since rewiring may be prohibitively expensive
for some homes (e.g., split-levels with no unfinished
areas), the Commission staff attempted to find a repair
method which would permit the continued use of existing
old technology aluminum wire. The main criteria to be
met by such a repair method are:
-
It must permit the repair of every
connection to, or splice between, aluminum wire in
the home;
-
The
repaired connections must be permanent but must
result in a system that can be maintained without
the need for special switches, wall outlets or other
connectors;
-
The
repair technique must be practical for use in an
occupied and furnished home.
The CPSC-sponsored research, laboratory
tests, and demonstration projects identified only one
method of repairing existing aluminum wire circuits
which meet these criteria. That repair is known as the
crimp connector repair.
The crimp
connector repair consists of attaching a piece of copper
wire to the existing aluminum wire branch circuit with a
specially designed metal sleeve and powered crimping
tool. The metal sleeve is called a COPALUM parallel
splice connector and is manufactured only by AMP
Incorporated. This special connector can be properly
installed only with the matching AMP tool. This tool
makes a permanent connection that is, in effect a cold
weld. An insulating sleeve is placed around the crimp
connector to complete the repair.
Two other
repair methods are often recommended by electricians.
While these repair methods are substantially less
expensive than COPALUM crimp connectors, neither of
these repairs is considered acceptable by the Commission
staff.
1. The
first repair (“pigtailing”) involves attaching a short
piece of copper wire to the aluminum wire with a
twist-on connector sometimes called a wire nut; the
copper wire is connected to the switch, wall outlet or
other termination device. The Commission staff has
evaluated the effectiveness of "pigtailing" as a
repair. In CPSC-sponsored laboratory testing some
brands of twist-on connectors have performed very
poorly. Over time, substantial numbers of these
connectors have overheated in laboratory tests. Surveys
of and statements made by electricians and electrical
inspectors confirm the highly variable and often poor
performance of these connectors when used with old
technology aluminum wire. It is possible that some
pigtailing “repairs” made with twist-on connectors may
be even more prone to failure than the original aluminum
wire connections. Accordingly, the Commission staff
believes that this method of repair does not solve the
problem of overheating present in aluminum branch
circuits.
2.
The other
repair recommended by the industry uses switches and
outlets labeled "CO/ALR".
Underwriters Laboratories, Inc.
(UL) lists these devices especially for use with
aluminum wire, although they can be used with copper or
copper-clad wire.
CO/ALR
devices perform better with aluminum wire when installed
carefully and according to best electrical practices
than do the types of switches and outlets usually used
in the original installations of old technology aluminum
branch circuit wiring. However, CO/ALR
connectors are not available for all parts of the wiring
system (for example, for permanently-wired appliances
and ceiling mounted light fixtures). In the opinion of
the Commission staff CO/ALR
devices must be considered to be, at best, an incomplete
repair. Further, CO/ALR
wiring devices have failed in laboratory tests when
connected to aluminum wire typical of that installed in
existing homes. The test conditions simulated actual
use conditions; no “overstress” type of testing was
used.
EXCEPTION:
If you have an aluminum wire termination in your home
which exhibits symptoms of failure, twist-on connector
pigtails or CO/ALR
devices may
be used as an emergency temporary repair for a failed
aluminum termination. Should such a repair be
performed, the Commission staff recommends that you
arrange to have your home rewired or the
COPALUM crimp connector repair performed as soon as
possible.
It is important to note that there is
only one manufacturer of the special connectors and the
tools required to make the repairs recommended by the
CPSC staff.
Warning
There are many other brands and types of
crimp connectors including those intended to be
installed with a pliers type of hand tool - which are
readily available to consumers at hardware stores,
lumber yards, hobby supply stores, automotive supply
stores, and so forth.
THE
COMMISSION STAFF DOES NOT BELIEVE THAT THESE COMMON
VARIETIES OF CRIMP CONNECTORS CAN BE USED TO RELIABLY
REPAIR ALUMINUM WIRING.
The Copalum Crimp Method of
Repair
The
precision dies in the COPALUM tool squeeze the connector
and wires into a particular shape which was determined
during the design of the COPALUM wire connector. Both
the final shape of the connection and the amount that it
is squeezed (deformed during crimping) are critical in
making a reliable crimp connection. Upwards of 10,000
pounds of force is necessary to obtain the amount of
deformation for which the connector is designed.
In
addition, electricians who are authorized to install
COPALUM connectors are thoroughly trained by the
manufacturer to use the tool properly. The Commission
staff emphasizes that this training is necessary to
assure that the electrician uses the careful,
professional workmanship required to make the crimp
connector repair safe and reliable.
Crimping Procedure
Follow the procedure below with attention
given to steps 1 through 4.
1. Use
the correct tool and dies (recommended by the AMP field
representative) for the splice being crimped. Ensure
that the color coding and marking designation on the
splice correspond to the color coding and marking
designation on the tool.
2. Be
sure the perforated liner is inside the splice. The
ends of the liner are flared to prevent removal.
3. Load
the splice into the dies of the tool.
4. Insert
stripped wires into the splice until the ends of wires
extend beyond end of the splice. Wires should be
parallel in the splice. Insulation of the wire MUST NOT
ENTER the splice.
You should request a copy of AMP
literature from your electrician prior to his beginning
work. Discuss with your electrician any information in
the literature which you do not understand. Remember
every connection of aluminum-to-aluminum or
aluminum-to-copper wire in your home should be repaired
in order to obtain the maximum benefit from such repair
work.
All appliances connected directly to
number 12 or number 10 aluminum branch circuit wiring
(for example, dishwashers, cooking equipment, heaters,
air conditioners and light fixtures) must be repaired in
addition to wall outlets, switches, junction boxes and
panel boxes.
To
determine whether the COPALUM crimp connection method of
repair is available in your area, you may wish to write
or call the manufacturer of the COPALUM connector for a
list of authorized electricians who are doing aluminum
branch circuit repair work in your area. You may write
to:
AMP Incorporated
Attn: Aluminum Wire Repair Program
Mail Stop 140-13
P.O. Box 3608
Harrisburg, PA 17105-3608
PHONE: 1-800-522-6752
The Commission staff wishes to remind you
that all modifications and additions to your wiring
system should be done in accordance with local
regulations and inspected by municipal authorities. You
should insist that repairs to your aluminum wiring be
inspected.
NOTE:
The preceding text is
adopted from
U.S. Consumer Product
Safety Commission
Publication 516
(REPAIRING ALUMINUM
WIRING).
This is provided for your information. Since the
recommendations regarding aluminum wiring can change,
you should visit the
U. S. Consumer Product Safety
Commission web site,
and obtain a copy of
Publication 516 (REPAIRING ALUMINUM WIRING)
to get the latest information.
For further information
on aluminum wiring, we recommend visiting
Inspect-ny.com
and
Heimer Engineering
