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Aluminum Wiring Replacement
In North American residential construction, aluminum wire was used to wire entire houses for a short time from the late 1960s to the late 1970s during a period of high copper prices. Wiring devices (outlets, switches, fans, etc.) at the time were not designed with the particular properties of aluminum wire in mind and there were problems with the properties of the wire itself. Older wiring devices not originally rated for aluminum wiring present a fire hazard. Revised manufacturing standards for wiring devices were required.
Upgrading or repairing aluminum-wired homes:
Flat 81 is waiting to be upgraded from Soviet-era aluminum cable to modern copper cable.
Several upgrades or repairs are available for homes with pre-1974 aluminum branch circuit wiring:
Completely rewiring the house with copper wires:
“Pigtailing” involves splicing a short length of copper wire (pigtail) to the original aluminum wire, and then attaching the copper wire to the existing electrical device. The splice of the copper pigtail to the existing aluminum wire uses special wire nuts, special crimp connectors, or special miniature lug-type connectors.
The U.S. Consumer Product Safety Commission (CPSC) recommends one of two alternatives for a permanent repair via pigtailing. The more extensively tested method uses special crimp connectors called COPALUM. As of April 2011, the CPSC has also approved miniature lug-type connectors called AlumiConn connectors. Any repairs should be done by qualified electricians familiar with aluminum wire problems and repair methods.
COPALUM connectors use a special crimping system that creates a cold weld between the copper and aluminum wire, and is considered a permanent, maintenance-free repair. These connections are sometimes too large to install in existing enclosures. Surface enclosures or larger enclosures may be installed to remedy this problem. COPALUM connectors can be costly to install and require special tools and electricians certified to use them. It can be difficult to find local certified electricians and there can be limited space in existing enclosures for these connectors.
The AlumiConn miniature lug connector can also be used for a permanent repair. The AlumiConn pigtail connectors only require the electrician to use a special torque screwdriver. These connectors may have the same problem with limited enclosure space as the COPALUM system.
Special twist-on connectors have been sold for joining aluminum to copper wire, which use a special antioxidant paste containing zinc dust in a low-residue polybutene base intended to prevent corrosion of the connection. CPSC considers the use of pigtails with wire nuts a temporary repair, and notes that “some pigtailing ‘repairs’ made with twist-on connectors may be prone to even more failures than the original aluminum wire connectors.” Ideal No. 65 “Twister” wire nuts, which are a distinctive purple color, are listed by UL for repairing aluminum wiring, but some researchers have criticized that UL listing. Ideal has stated that the Twister is intended for pigtailing leads of ceiling fans and light fixtures and is not intended for full retrofits.
CO/ALR devices (switches and receptacles) should be used in place of older receptacles that did not have the proper rating, and they should be used to replace devices used in homes with aluminum branch circuit wiring. These devices are tested and listed for both AA-1350 and AA-8000 series aluminum wire, and are acceptable according to the National Electrical Code.