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ALUMINUM WIRING HAZARDS & REPAIRS
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Repairing Aluminum Wiring - US CPSC Publication 516: This is the original U.S. CPSC document explaining the hazard of solid conductor aluminum electrical circuit wiring, and recommending the use of the AMP TYCO COPALUM special crimp connector to pigtail copper to the aluminum wires as an alternative to complete re-wiring of the building. This document was scanned from the original CPSC document explaining how to recognize the presence of an aluminum wiring hazard and how to repair aluminum wiring. Edits or comments by Daniel Friedman, added for clarification, update, or to provide links to current sources of the AMP COPALUM Connector equipment and specifications are included in this document in [italicized brackets.] For in-depth information about the aluminum wiring hazard and for description of alternative repair methods when the methods recommended here are not available, see More Information below. Readers are welcome to make and freely distribute printed copies of this article. For the latest US CPSC publication on aluminum electrical wiring see Aluminum Wiring - CPSC Publication #516-PDF.
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ALUMINUM WIRING [the history of aluminum electrical wiring and the aluminum branch circuit wire fire hazard]
U.S. Consumer Product
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 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 dealers' shelves however, continued after 1972.
Signs of trouble in aluminum wire systems include warm-to-the- touch face plates on outlets or switches, flickering lights, circuits that don't work, or the smell of burning plastic at outlets or switches.
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.
1 The survey conducted by the Franklin Research Institute defined "Fire Hazard Conditions" to occur when receptacle cover plate mounting screws reached 149~C (3O0~F), or sparks were emitted from the receptacle, or materials around the receptacle were charred.
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.
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:
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.
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 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.
Follow the procedure below with attention given to steps 1 thru 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 #12 or #10 AWG 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:
[DJF NOTE: the following address which appears in CPSC #516 is OBSOLETE]
[15 January 2008 DJF note: We add the following update and detail to this US CPSC document: Consumers and electricians may have difficulty obtaining further information, advice, or equipment from AMP or the successor distributor, TYCO, for the COPALUM connector and aluminum wiring repair. Consumers and electricians needing to evaluate or repair aluminum wiring should see Reducing the Fire Hazards in Aluminum-Wired Homes, details of the hazard of and what to do about aluminum wiring, aluminum wiring repair methods, aluminum wiring failures research, field and lab experience, expert sources. This document answers most technical questions about the hazards and remedies of aluminum electrical wiring.
[DJF NOTE: ] Consumers or electricians looking for access to the "AMP" COPALUM connectors and special crimping tool should contact Tyco Electronics:
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.
[DJF note: Consumers should make certain that their electrical inspector or electrician is fully familiar with the hazards of aluminum electrical wiring, and fully trained in proper repair methods for aluminum wiring. Improper repairs using improper devices or equipment, or incomplete repairs, such as failure to address every connection in the building, or using non-recommended parts and devices, may actually increase the risk of a fire or loss.]
The following advice is excerpted from ALUMINUM WIRING GUIDE for HOME INSPECTORS and was not part of the original US CPSC document.
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