Aluminum & Copper Wiring
What's the difference?
•Not all aluminum wiring is hazardous, aluminum wiring can be safe if properly utilized. •Things like high voltage transmission lines and even the service entrance conductors feeding you home are usually aluminum. •So whats the big deal with aluminum wiring? •When used as smaller conductors (Like AWG#10 for a 20 AMP circuit or AWG#12 for a 15 amp circuit in a home) aluminum wiring can be hazardous.
What Makes Aluminum Wiring Unsafe?
Here are some reasons why small aluminum conductors make a poor substitute for copper. •Aluminum is not as conductive as other metals like copper. •Because it has a higher resistance, and because of its metallic properties, aluminum expands and contracts under loads significantly more than copper. •As the "load" or amperage increases on the conductor it begins to expand, and when the load decreases, the conductor contracts back to its initial size. •The constant expansion and contraction or aluminum wire, combined with oxidation, cause terminations in wire connectors, and on devices such as outlets and switches, cause them to become loose. •When the wiring becomes loose, it will arc, and arcing will eventually lead to a fire.
For larger appliances and large "feeders" aluminum does not pose as big of a problem. The connection methods for the larger wires take this expansion and contraction into account. Additionally anti-oxidant compounds are required on these connections.
What the National Electrical Code 2005 Says About Aluminum Wiring Devices
•Receptacles rated 20 amps or less and designed for the direct connection of aluminum wire shall be marked CO/ALR. •Switches rated 20 amps or less directly connected to aluminum wire shall be marked CO/ALR. •What is CO/ALR? CO/ALR is a device that has specific characteristics minimizing the effects of aluminum expansion and contraction. This makes the device safer for a direct connection to an aluminum conductor.
What the Consumer Product Safety Commission Says About Aluminum Wiring Devices
An estimated 2 million homes have been constructed using aluminum wiring.
Trouble signs associated with aluminum wiring:
•Warm switch or outlet plates. •Strange or distinctive odor of burning plastic. •Flickering lights.
If your home has aluminum wiring and you have experienced any of these occurrences, call now!
Copper & Aluminum Approved Devices (CO/ALR)
•These devices were designed for the direct hookup of both copper and aluminum. •Each device will be marked CO/ALR or CU/AL. •Each device will also bear the UL listing symbol.
What is Pig Tailing? Should I Use It In My Home?
Pig Tailing is achieved by attaching a short piece of copper conductor at the end of the aluminum conductor, made safe by using a UL approved connector designed to connect copper and aluminum wire. When copper is added, you may then attach the wiring to any copper approved device, outlet, switch, appliance, ground fault receptacle, etc. The National Electrical code only approves UL listed connectors for this application, but does discourage the connections of two dissimilar metals, due to electrolytic action.
The consumer product safety commission recognized and supports pig tailing when using the approved UL listed products. Pig tailing should be utilized when designer devices or ground fault devices are being installed. The alternative to pig tailing is simply installing CO/ALR devices. When installed by a professional, these devices are both safe and inexpensive.
Larger Circuits & Aluminum Wiring
Larger circuits, like feeder circuits for breaker boxes, are in most cases safe even when using aluminum wiring. These are safe because of the special methods used in the installation of these conductors and their respective connectors. Large circuits are desinged with aluminum wiring in mind.
Anti-Oxidant Compounds & What They Do
Anti-Oxidant compounds, if properly used, minimize the effects of oxidation on the aluminum conductor. This results in a better, connection and an ultimately safer system.