How to identify copper clad aluminum wire?


For technical reasons, it is useful to recognize what c […]

For technical reasons, it is useful to recognize what copper-clad aluminum wire looks like. For example, the wire gauge or diameter size of copper clad aluminum wire will follow the same physical dimensions as solid aluminum wire. The 15 amp circuit will be connected using #12 aluminum wire, #12 copper-clad aluminum wire, or #14 solid copper wire.

Wire sizes required for electrical outlets for common household branch circuit wiring, and SE cable and branch circuit wire sizes versus amps, including wire sizes from #14 AWG to 4/0 AWG. From the outside, if we don't pay attention to the printed labels and markings that may be present on the copper-clad aluminum wire, and if we just look at the wire itself, strip off the insulation, the wire looks like copper.

Look at the cut end of the "copper" wire and you'll notice that the cut end looks silver, which is a clear sign of the wire's aluminum core. Silver cut ends are always present, but hard to spot for two reasons:
1. Oxidation turns aluminum gray. Older wiring copper-clad aluminum wire ends that were initially shiny silver when the first cut will oxidize to an easy-to-miss gray. Also, almost any copper-clad aluminum wire you find in buildings today will be old.
2. Conical extruded copper overlaid aluminum. The silver aluminum wire ends will also be covered by the wire's outer copper cladding, which is usually squeezed by wire cutters when cutting the wire. When initially cutting CU-CLAD AL wire, the wire cutter will not produce square-cut wire ends. Instead, clamp the wire ends at an angle, further extruding the copper cladding against the aluminum, which may be visible on the wire ends.

However, if we look closely at the relatively square-cut end of the wire, we should see the aluminum core surrounded by the copper sheath. It's important to note that filing wire ends to show aluminum core is not something a home inspector or electrical inspector would typically do in the field. Obviously, you need to turn off the power to the circuit first to avoid a serious electric shock.

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