Aluminum wiring facts for kids

A fire almost started here due to oxidized aluminum wire

Aluminum wiring is a type of electrical wire made from the metal aluminum, instead of the more common copper. It is widely and successfully used for carrying electricity over long distances, like on big power lines. It is lighter and stronger than copper wire, which helps prevent the cables from sagging. It is also less expensive than copper wire. Aluminum wiring has also been used successfully in aircraft. In the 1960s, when the price of copper went up, electricians started to use aluminum to wire homes and other buildings. However, this use of aluminum wiring was not successful and became a major safety problem. Because of these safety problems, it was stopped for use in building wiring in the mid-1970s.

Why Aluminum Wiring Can Be Dangerous

Over time, aluminum wiring can cause problems in homes. Here's why:

• Loose Connections: The aluminum wire can slowly pull away from the screws on electrical outlets, light switches, or light fixtures. This creates a loose connection.
• Heating Up: A loose connection makes it harder for electricity to flow smoothly. This causes the wire to heat up, much like a narrow pipe makes water flow faster and build pressure.
• Oxidation: When aluminum heats up, it can react with the air and form a layer of "rust" called oxidation. This oxidation makes the connection even worse and causes more heat.
• Fire Risk: This cycle of heating and oxidation can get worse and worse, eventually leading to very high temperatures that could start a fire.

Problems with Repairs

Trying to fix aluminum wiring incorrectly can make the problem even worse.

• Mixing Metals: Connecting aluminum wire directly to copper wire with common twist-on connectors (often called "wire nuts") is very dangerous. Aluminum and copper expand and contract differently when they heat up and cool down. This difference can make the connection even looser over time.
• Special Connectors: Even some twist-on connectors that claim to be designed for aluminum to copper connections can still be risky.

Proper Ways to Repair Aluminum Wiring

The only safe and proper way to repair aluminum wiring is to use special methods and connectors.

• Pigtailing: This involves connecting the aluminum wire to a short piece of copper wire, called a "pigtail."
• Approved Connectors: These connections must be made with special crimped or screw-on connectors that are specifically designed and approved for connecting aluminum to copper wires. These special connectors ensure a tight and safe connection that won't loosen over time.

Images for kids

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  New York City utility lines in 1890.

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  Modern 500-kV overhead power lines used in an electrical power distribution system supplied by a utility

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  Larger electrical cable that has stranded aluminum wires with an outer sheath used for service entrance feeders from a meter to a panel

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  Solid aluminum branch circuit wire (top) and solid copper branch circuit wire (bottom)

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  Larger stranded aluminum wire at termination lugs of a disconnect

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  Older solid aluminum wire at older receptacle with steel terminal screws

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  Special CO/ALR rated wall outlet and wall switch

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  AL to CU Pigtail done with COPALUM crimp connectors

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  Ideal no. 65 Al-Cu twist-on wire nut with distinctive purple color