Aluminum to Copper
Aluminum to Copper Wire Changeover
Household wiring in most Maryland homes is made of copper, with aluminum wiring used only for specified heavy duty conections (for example, heavy aluminum wire is normally used for the incoming electric mains, and frequently from the circuit breaker panel to such things as the electric oven, the water heater, the dryer, or the central air conditioner).
But during the period from 1965 through 1973, the price of copper skyrocketed, causing builders to look for an alternative. The only alternative was aluminum, so they began to use aluminum wire for normal household wiring lines. This was also a record-breaking period for new home construction. As a result hundreds of thousands of houses were built with aluminum wire.
The problem with aluminum wiring use in general household service is in the way it was used, not in the wire itself; builders used it just as if it were copper wire despite the fact that any electrician should have known that the metals have different characteristics. A heavier aluminum wire is required to carry the same volume of electricity as the copper wires for which the electrical codes were designed.
When aluminum wire is slightly overloaded, it heats up; when it heats, even slightly, it expands; when it expands very slightly hundreds of times over the years, it tends to work loose at outlets, switches, or where it connects with copper fittings that don't expand. When it works loose, an arcing or short circuit can occur, and either one on any wire can start a fire. And fire here is a particular threat since aluminum wire burns.
In 1974, after several spectacular losses of life, the code was changed. No homes have been built since then with aluminun household wire. (Remember this does not concern thos heavy duty 220 volt aluminum wires from panels to appliances).
It is vital, potentially life saving, to have any aluminum problems corrected.
What is involved?
Each outlet and light switch is opened and checked to see if it is Aluminum wired and has not already been "pigtailed" which involves splicing a short length of copper to the original aluminum. If the switch or outlet needs changing over the electrician will either replace the outlet, or add a pigtail with an antioxidant filled wire nut, or properly install a bimetallic connector. Then re-install each outlet or switch.
The Circuit breaker panel is also opened; the wire connections are covered with an antioxidant and the fittings tightened.
Key Points to Remember:
- 1965 - 1973 is the period; perhaps 1/2 of all homes built then were involved
- Aluminum household wiring is a significant fire hazard if corrective actions are not taken but is safe afterwards
- Aluminum wiring to heavy duty (220 volt) uses is not involved
- Correction should be done by a licensed electrician