How to Use Aluminum Wiring Safely
What is Aluminum Wiring?
Aluminum wiring refers to electrical wires made from aluminum metal rather than the more common copper metal.
Aluminum became a popular substitute for copper wiring in American homes built between 1965 and 1973 because it was cheaper and more readily available at the time. The aluminum used in home wiring is nearly pure aluminum metal formed into wire strands.
Unlike copper, aluminum has some properties that make it more prone to problems when used for electrical wiring:
Aluminum expands and contracts more with temperature changes compared to copper. This can loosen connections over time.
Aluminum conducts electricity less efficiently than copper, leading to some overheating issues.
Aluminum corrodes more easily than copper when exposed to air and moisture. This can increase electrical resistance.
Potential Hazards of Aluminum Wiring
The main safety concern with aluminum wiring is the potential for loose connections leading to overheating. Some specific hazards include:
Loose connections: As aluminum wires expand and contract with temperature, connections can loosen over time. This can increase electrical resistance and cause wires to overheat.
Corrosion: Aluminum readily forms an insulating aluminum oxide coating when exposed to air. This coating increases resistance and can cause overheating issues.
Poor terminations: Outdated connection methods like soldering or poor quality connections can compound problems for aluminum wires.
These factors can lead to overheating and arcing faults, which can start electrical fires inside walls and ceilings. So extra care needs to be taken with aluminum wiring to prevent loose connections and corrosion issues.
Inspecting Aluminum Wiring
If your home was built between 1965-1973, the first step is to check if aluminum wiring was used. Visual signs include:
- Wire sheathing labeled "Aluminum"
- Wires with dull matte finish rather than copper's bright orange color
- Wires marked "AL" rather than "CU" on circuit breaker panels
An electrician can use a multimeter to check wire material by conductivity. Aluminum conducts about 60% as well as copper.
Thoroughly inspect connections for signs of looseness, corrosion, overheating:
- Loose, overheated outlets and switches
- Discolored, warm wires at connections
- Cracked wire sheathing
Also check appliances like stoves, dryers etc. and exposed wiring like in attics.
Upgrading Aluminum Wiring
Replacing all aluminum wiring with copper is the best option, but can be cost prohibitive. Some more affordable upgrades include:
Pigtailing: Copper pigtails are attached to existing wires with special connectors. Improves compatibility at outlets and switches.
CO/ALR switches: Special switches designed for copper-aluminum connections. Reduce resistance and overheating.
Alumiconn connectors: Replace old connections with new connectors designed for aluminum. Tighten to spec.
Arc-fault circuit breakers: These advanced breakers detect dangerous arcing and shut off power. Provide protection if arcing occurs.
To use aluminum wiring safely over the long term:
Have an electrician routinely check connections for tightness and heat. Tighten or replace as needed.
Check for cracked, damaged wire sheathing and exposed wires. Have repaired immediately.
Never overload circuits or use high-wattage appliances on aluminum wiring.
Shut off and disconnect aluminum wiring before doing any electrical work.
Consider having aluminum remediated or replaced if safety issues persist.
The risks of aluminum wiring can be managed with proper inspections, maintenance, and upgrades. Replacement with copper wiring is the ultimate solution. But other options exist to improve safety at more reasonable cost.
Warning Signs of Unsafe Aluminum Wiring
Here are some key warning signs that indicate potential safety issues with aluminum wiring:
Hot outlets or switches - if you feel heat or smell odd odors around an outlet, this could indicate a bad connection
Light fixtures flickering - if lights dim or flicker unpredictably, it can point to a loose wire connection
Circuit breakers tripping - circuits randomly tripping for no obvious reason may be caused by arcing faults
Buzzing sounds from outlets - buzzing or crackling noises are a warning of arcing problems
Discolored wires - overheated copper-aluminum connections can turn wires dark or oxidized
Visible sparks or smoke - sparks, smoke and burning odors means dangerous arcing is occurring
Any of these warning signs suggest you should have an electrician inspect the aluminum wiring right away. Leaving these issues unattended risks electrical fires or shocks.
Frequently Asked Questions
Is it safe to use outlets with aluminum wiring?
Outlets wired with aluminum can be safe if proper connectors are used and connections are tight. But they require more vigilance to check for overheating problems. Avoid using high-wattage appliances in aluminum-wired outlets.
What kind of switches should be used with aluminum wiring?
Special CO/ALR rated switches, marked for use with copper and aluminum, are recommended. They are designed to reduce heat buildup. Standard switches have more potential for overheating failures.
Should aluminum wiring be replaced with copper?
Replacing all aluminum wiring with copper is the best long-term solution, but can be very expensive. Upgrades like pigtailing and Albiconn connectors can improve safety at lower cost. Routine maintenance is also essential.
How much does it cost to replace aluminum wiring?
The cost to replace all wiring varies greatly based on house size and complexity. As a rough estimate, it may cost $8,000 to $15,000 to replace all the wiring in a typical single family home. Get quotes from electricians.
Is aluminum wiring banned?
Pure aluminum wiring was banned for use in North American homes by the Consumer Product Safety Commission in the 1970s. Special alloys using small amounts of copper or other metals were later allowed.