Comparing cable types
Copper vs aluminum wire: what changes the value
Copper and aluminum are both purchased, but they are not interchangeable and they are not priced the same. Confusing the two is the most common reason a surplus quote comes back wrong.
The difference is physical: aluminum conducts less efficiently per unit of cross-section, so it is used in larger sizes for the same ampacity. It is also roughly a third of the weight, which is why an aluminum reel that looks identical to a copper reel feels noticeably light.
Where each one shows up
Copper dominates branch circuits, control wiring, grounding and anything where space or termination quality matters. Aluminum dominates large feeders, service entrance cable, URD and utility distribution, where weight and cost favor it at large sizes.
Tennessee work uses both heavily. Multifamily and commercial feeders are often aluminum; hospital and industrial work is usually copper. A single jobsite can produce both, which is why the quote form asks you to separate them.
How to tell them apart
Read the print. Cable marked AL or ALUMINUM is aluminum; CU or COPPER is copper. AA-8000 is the aluminum alloy used for building wire. If the print is gone, a magnet will not help — neither metal is magnetic — but weight and the color of a cut end will: aluminum is bright silver-white and oxidizes dull gray, copper is reddish and oxidizes brown.
Why it matters for the quote
Metal is the first input in value. A lot described as copper that turns out to be aluminum will be re-quoted, which costs a week. Stating the metal clearly on the form, even as “both” or “not sure”, gets you an accurate number sooner.
| Copper | Aluminum | |
|---|---|---|
| Typical use | Branch circuits, control, grounding | Feeders, service cable, URD, utility |
| Weight | Heavy for the same ampacity | About a third the weight |
| Common constructions | THHN, XHHW-2, MC, bare | XHHW-2, THHN, SER, SEU, URD, USE-2 |
| How to identify | Print says CU or copper; reddish cut | Print says AL, ALUMINUM or AA-8000; silver cut |
Questions about this
Is aluminum wire worth selling?
Yes. AA-8000 building wire, SER and URD are purchased routinely, at aluminum value rather than copper value.
Can a lot contain both metals?
Yes. List them separately so each is priced against the right metal.
What does AA-8000 mean?
It is the aluminum alloy series required for building wire conductors, formulated for better termination performance than older utility aluminum.