CO/ALR
Definition and meaning of CO/ALR in real estate.
CO/ALR is a designation stamped on electrical receptacles and switches indicating they are certified for use with copper, aluminum, or copper-clad aluminum wiring. This safety certification ensures that the device's terminals are constructed to prevent dangerous corrosion and heat buildup when connected to aluminum conductors.
In more detail
Aluminum wiring was widely installed in homes built during the late 1960s and early 1970s due to the high cost of copper. However, aluminum expands and contracts more than copper under electrical load, which can loosen connections and pose a fire hazard. Devices marked CO/ALR, which stands for copper/aluminum revised, use specific metals in their terminal screws to mitigate these thermal expansion differences. Home inspectors and electricians search for this designation when evaluating older homes with original aluminum electrical systems.
Key facts
| Category | Property Types & Construction |
|---|---|
| Stands for | Copper/Aluminum Revised |
| Watch out for | Standard outlets connected to aluminum wiring can cause house fires |
| Applies to | Electrical switches and outlets in older homes |
During a home inspection of a house built in the early 1970s, the inspector verifies that all the wall outlets have the CO/ALR stamp to ensure they are safe for the home's aluminum wiring.
Frequently asked questions
Why is aluminum wiring dangerous with standard outlets?
Aluminum oxidizes and expands differently than copper, which can cause loose connections, electrical arcing, and potentially start a fire if standard outlets are used.
Can I use CO/ALR devices in a home with copper wiring?
Yes, CO/ALR devices are fully rated and safe for use with standard copper wiring as well as aluminum wiring.