CU / AL
Definition and meaning of CU / AL in real estate.
CU/AL is a label printed on electrical devices, such as outlets and switches, indicating they are approved for use with both copper and aluminum wiring.
In more detail
Copper, abbreviated as CU, and aluminum, abbreviated as AL, have different physical properties that can cause issues if they are connected improperly. When aluminum wire is attached to a standard copper-only outlet, it can corrode or expand at different rates, potentially loosening the connection and creating a fire hazard.
Devices marked with the CU/AL rating are specially designed to prevent this dangerous reaction. Home buyers and inspectors should look for these markings in older homes built during the era when aluminum wiring was common.
Key facts
| Category | Property Types & Construction |
|---|---|
| Meaning | Copper (CU) and Aluminum (AL) compatible |
| Purpose | Preventing electrical fires and corrosion |
| Required in | Homes with aluminum branch wiring |
An inspector checks the electrical outlets in a house built in the early 1970s to verify they have the CU/AL rating.
Frequently asked questions
Why is the CU/AL rating important in older homes?
Many homes built in the late 1960s and early 1970s used aluminum wiring, which requires compatible CU/AL outlets to prevent overheating and fire risks.
Can you connect copper and aluminum wires directly to each other?
No, they should not be twisted together directly without a specialized wire connector approved for joining copper and aluminum.
How can a home buyer identify aluminum wiring?
Aluminum wiring can be identified by its silver color or by looking for the word "ALUMINUM" printed on the plastic wire jackets in the attic or electrical panel.