I want to use aluminum wiring in my home, but I'm concerned about the potential for electrical fires. Aluminum wiring was used extensively in North American homes in the 1960s and 1970s before being phased out due to safety concerns. Aluminum is a great conductor of electricity, but it expands and contracts at different rates compared to copper. This can lead to loose connections and overheating at outlets and switches, which can start fires. However, with the proper precautions and maintenance, aluminum wiring can be used safely. Here's what I need to know.
Dangers and Risks of Aluminum Wiring
Before using aluminum wiring, it's important to understand the potential risks and dangers if not installed and maintained properly:
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Loose connections - Aluminum wire expands and contracts more than copper. This can lead to loose wire connections at outlets and switches over time. Loose connections generate heat which can melt plastic and start fires.
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Galvanic corrosion - When aluminum and copper come into contact, galvanic corrosion can occur. This accelerates loosening of connections.
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Higher resistance - Aluminum has a higher resistance than copper, which causes more heat generation in the wiring. This builds up over time.
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Brittle wires - Pure aluminum wiring is stiffer and more brittle than copper. This can cause breakage at connection points over repeated bending and movement.
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Difficult to install - Electricians require special training and techniques to properly install aluminum wires due to their unique properties. Improper installation heightens fire risks.
These factors can combine to make aluminum wiring prone to overheating and fire hazards if not properly installed and maintained. Fires typically start at outlets and switches where loose connections generate dangerous levels of heat.
Proper Installation Methods
If using aluminum wiring, it's critical that a licensed electrician use the proper installation techniques:
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CO/ALR rated switches/outlets - Use connectors labeled CO/ALR. These are specially designed to join copper and aluminum wires and resist galvanic corrosion.
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Anti-oxidant paste - An oxide-inhibiting paste should be applied to all connections to prevent corrosion and loosening.
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Proper torque - Wire connectors must be tightened to the proper torque specifications to avoid looseness while avoiding damage to the aluminum wire.
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Breaker sizes - Because aluminum has higher resistance, larger breaker amp sizes may be required to handle the increased heat output under load.
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Splicing pigtails - Copper pigtails spliced to the aluminum wires using special connectors is recommended to reduce heating and corrosion at devices.
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Proper wire sizes - Thicker gauge wire may be required compared to copper installations to account for the higher resistance in aluminum.
Ongoing Inspections and Maintenance
Regular inspections and maintenance are critical for existing aluminum wiring installations to catch any loosening connections before they become fire hazards:
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Visually inspect wires and connections for any damage, wearing, overheating signs, or corrosion. Any issues should be fixed immediately.
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Check outlet and switch connections for tightness. Retorque loose connections and apply more anti-oxidant paste.
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Check breakers and fuses to ensure proper amp sizes are used for the aluminum wiring gauge. Upsize any undersized breakers.
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Consider replacing old style outlets and switches with CO/ALR rated ones and add copper pigtails if not present. This significantly reduces fire risks.
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Electricians recommend inspecting aluminum wiring every 5 years or during any remodeling or changes to the electrical system.
Replacing Aluminum Wiring with Copper
For maximum safety and peace of mind, replacing all aluminum wiring with copper is recommended whenever remodeling or upgrades are performed:
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Copper wiring does not suffer the oxidation, expansion/contraction, and connection issues inherent to aluminum. This eliminates the fire risks.
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However, full replacement with copper can be expensive. Prioritize high use circuits first, such as kitchen, laundry, and bathrooms.
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Use qualified electricians when replacing aluminum wiring, as improper installations can be dangerous.
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Consult local building codes - some jurisdictions now require copper wiring in any remodeled circuitry.
While aluminum wiring can often be used safely, it does require vigilance and proper maintenance to avoid fire risks. Follow these best practices, and consult with qualified electricians throughout the process. With the right precautions, aluminum can provide an affordable and reliable wiring solution. But extra care is required compared to copper.