The problem with aluminum wiring-
Aluminum wiring was used for small branch circuits, that is the circuits that service 15-20 amp loads throughout the house, were installed in homes during the late 1960’s through 1976. During this time period several problems associated with aluminum conductors were found.
First, the relatively low melting point of aluminum as compared to that of copper causes the conductors to fail during excessive loading and during short circuits. This failure can cause excessive heat which can lead to fires and damage to appliances and other loads connected to the circuits.
Second, as aluminum oxidizes, it forms an aluminum oxidation at the micron level that is highly resistive. Resistance in a circuit causes heat. The more heat in a circuit, the more resistance, the more resistance, the more heat. This condition is self-perpetuating. As mentioned above, this condition can lead to fires or damage to connected loads.
Third, connection of dissimilar metals causes an electrochemical event where the aluminum conductor usually becomes the anode or the point in the circuit where oxidation occurs. This electrochemical process causes rapid deterioration of the metal which usually results in conductor failure causing short circuits, fires, and equipment damage or circuit failure.
Finally, the properties of aluminum cause for the rapid expansion and contraction of the metal during normal usage. This process can actually loosen terminations either at the screw terminals of a device such as an outlet or light socket or even at the wire terminals such as a panel or wirenut connection.
There are a couple of different remedies for the branch circuit wiring mentioned above.
1. Conductor replacement- This is a costly remedy which usually requires drywall patching, painting and can cost $5-$7 per square foot of the finished area of the home. Although it is the only absolute permanent repair, the cost of this method of repair usually outweighs the benefit of such a repair.
2. Pig-tailing- This is the most cost effective means of combining aluminum conductors to copper conductors which eliminates most, if not all, of the above mentioned problems with the aluminum conductors. This is the method that we use with great success to repair aluminum wiring issues. By utilizing UL approved wire connectors, we combine the aluminum conductors to copper conductors. The copper conductors are then used to connect to the electrical devices such as light fixture, outlets, and other electrical loads. This can be done for $15-$18 dollars in most cases and includes new outlets and switches and the associated cover plates in plastic.
3. The proprietary method- There is a proprietary AL-CU method of pig-tailing. Although this method forms what is considered to be a permanent repair it revivals the cost of conductor replacement. This method costs $18-$22 per connection and most electrical devices have 3 connections. It does not include a new device or faceplate by most installers. Due to the excessive cost of this repair we do not perform this repair.