During the later 1960s and into the mid to late 70s, single strand (solid) aluminum Romex type wiring replaced copper, branch circuit wiring in many new residences. However, after a decade, inherent weaknesses in aluminum became more apparent. Over time, some people retrofitted their connections with copper leads, but many older homes still contain fixed aluminum wiring. Poor connections at devises such as wall receptacles, light switches, and poorly connected splices can cause overheating, and this situation may not necessarily trip the circuit breaker. The best thing to do if you have fixed aluminum wiring in your home, is to have your entire electrical system evaluated by a licensed electrician.
How to Identify Aluminum Wiring
On your switchboard, check for the symbol “AL” or word “Aluminum” which will be on the plastic wire jacket. Take a flashlight with you; it can be hard to spot! If your house has been around since the 1960s and 70s, then there is a greater chance that your wires are made of aluminum. To look inside the box, turn off the main breaker. Open the cover and look at the grounding bar inside the panel to see if aluminum wire is apparent. Turn off all branch circuit breakers before turning the main back on.
Safety of Aluminum Wiring
Aluminum is a soft metal, and it can expand or contract on heating or cooling. Copper also does the same but the rate at which both expand and shrink vary. Besides, most metals oxidize when exposed to oxygen; however, when copper undergoes oxidation, it forms a conductor, whereas aluminum forms a resistance, resulting in more heat which can affect the circuit breaker. Subsequently, this could cause electrical problems like dimming lights, power outages, fluctuations, and overloaded switchboards that can harm your devices and cause electrical fires. Always look out for signs of melting, and for the smell of burnt wires. Splice caps (wire nuts) will actually melt when loose splices are present.
Aluminum to Copper Connections
A qualified electrician can help you evaluate aluminum wiring. Keep in mind that not all licensed electricians have been trained in aluminum wiring problems. These are issues that younger electricians may not be familiar with. Therefore, you need to select the right service provider to ensure everything works properly, and to resolve any potential electrical problems with the circuit breakers within the shortest time possible. If your home contains aluminum wiring, the original circuit breaker panel is most likely obsolete as well.
Options for Al to Cu Connections
The options available for converting from aluminum to copper connections include:
- Copper rewiring: Rewire the house entirely, using copper Romex wires. Although an expensive approach, it is the best method in terms of safety. The existing aluminum wire may remain stapled to the studs & joists behind the drywall inside the walls and ceilings as long as it’s not connected to anything.
- Pig-tailing: Here, you need to attach a short section of copper wire (lead) to the existing aluminum wire, but aluminum to copper wires must be connected together using the proper materials, which include several methods. The copper lead connects to the switch or receptacle screws. This is one of the most effective ways of connecting aluminum and copper pigtails, and it is quite reliable. However, in some cases, pig-tailing with some different types of connectors can be hazardous. For a permanent repair, the U.S. Consumer Product Safety Commission (CPSC) recommends that pig-tailing be done with special crimp connectors, called COPALUM, or special miniature lug-type connectors, called AlumiConn connectors. However, this type of electrical repair should be done only by a certified electrician that is familiar with aluminum wire problems and repair methods. ALL aluminum connections, whether they be aluminum to aluminum, aluminum to copper, or aluminum to a devise screw must be coated with a special paste approved for aluminum connections. Noalox is one brand of paste.
- COPALUM Crimping. This connector repair comes with the option to attach pieces of copper wires to the existing wires. They have a special metal sleeve, powered by a crimping tool.
- AlumiConn Connectors. Approximately three years ago, in 2011, the U.S. CPSC approved the AlumiConn miniature lug connector as an alternate to the COPALUM connectors for a permanent repair.