After some time and an estimated 1.5 million installations, dangerous overheating was discovered at the 15- and 20-amp circuits due to the expansive and corrosive characteristics of the aluminum wiring within the circuit connections. At this point, the branch wiring was deemed by the NEC to be a potential fire hazard and all further installations ceased.
Multiple problem points were common at outlets and switches because of the expanding and contracting nature of the aluminum wiring, and subsequent movement or creep out of the connection. The wiring deteriorated (corrosion) to the point that overheating and arcing set the stage for serious fire potential. Actual fires were, in fact, documented.
Signs of premature failure of aluminum branch wiring observable to the homeowner may include:
- Unusually warm cover plates on switches and outlets
- A distinctive or strange odor in the vicinity of a switch or outlet
- Sparks or arcing at switches or outlets
- Flickering of lights
The first step to take if you have discovered that your home has this electrical component is to contact a licensed electrician. Do not attempt to 'DIY'. A professional electrician will be familiar with this situation and will know how to return your home to a safe environment.
The electrician's goal will be to evaluate and repair every connection within the home. Only at this point will the house be deemed safe. Here are three methods the electrician may use to remedy the problem without resorting to replacing all the wiring:
- COPALUM crimp connectors. This is the recommended method and will permanently bond the aluminum wire to a copper wire to every outlet, switch, and junction.
- CO/AL(R) switches and outlets. Every switch and outlet in the home will be replaced with those labeled CO/AL(R).
- Copper pigtailing. Electricians will occassionally attach copper wires between the aluminum wiring and outlets and switches by twisting the wires together in a fashion called pigtailing. While workable, this is probably the least desireable of the above three methods.
It should be noted that while the NEC approves these methods, the Consumer Product Safety Commission (CPSC) only approves the COPALUM method. (The CPSC also leans toward total replacement as a strong consideration.) There has been quite a bit of discussion between these groups, but the CPSC has not yet been convinced. Click on this link for a detailed white paper issued by the CPSC.
Bottom line: If you discover your home has single strand alumium wiring, you are strongly encouraged to take steps to bring it up to current-day standards. This will require the services of a certified and licensed electrician. It's a problem that should not be ignored.