Copper or aluminium: what changes.

Conductivity, size and the weight you lift

Copper conducts better than aluminium per unit of area, so an aluminium conductor has to be larger to carry the same current. A feeder that is 4/0 in copper is often 250 or 300 kcmil in aluminium. The cable grows in outside diameter, the bend radius grows with it, and the reel it ships on grows as well, which changes everything about how it moves.

Aluminium is far lighter for the same volume, and even after upsizing it usually comes out lighter per foot than the copper equivalent. That changes handling. A full reel of aluminium feeder can be moved with equipment that would not touch the copper version, and a coil of aluminium that two people can carry would need a lift in copper.

None of this changes what the cable is in principle, only what it takes to move and install it. A heavier reel needs a bigger forklift, a wider gate and a longer lift plan. Lighter aluminium buys convenience at the cost of a larger diameter, and the two trade against each other in almost every feeder decision on a Houston site.

• Aluminium needs one or two sizes up for the same ampacity
• Copper wins on diameter and on space inside a conduit
• Aluminium wins on weight per foot and on reel handling
• Aluminium appears mainly above 1/0; copper runs 14 AWG up

Terminations decide where each metal can go

Aluminium terminates differently. The oxide that forms on the surface is resistive, so the conductor has to be cleaned and treated, and every connector must be listed for aluminium rather than copper only. Aluminium also creeps under a lug over time, which is why torque and re-torque practice matters more on aluminium joints than on anything in a copper panel.

For a seller, the consequence is that aluminium cable with damaged or cut back ends is harder to reuse. A copper conductor can be re-terminated with ordinary lugs and a crimper. An aluminium one needs the right connector, the right compound and somebody who knows the procedure, and that labour follows the cable to whoever takes it next.

Mix the two metals and the question gets sharper. A lot with copper feeders and aluminium SER in the same pile has to be split before either part can be judged, because the terminations, the handling and the metal all differ. Say which reels are which, where the labels survived, and the review will not guess from a photograph.

How each metal survives a Gulf Coast yard

Copper corrodes where moisture and salts reach it, going green and then black, and it does so fastest at a cut end where the strands stand exposed to air. Aluminium oxidises almost at once, forming a grey film that protects the metal in storage but ruins a termination if it is not removed before the lug goes on.

Both suffer water wicking into an open end. In Houston, with salt air near the Ship Channel and months of high humidity, an unsealed end is the most common defect on stored cable. Copper tends to show it earlier and more visibly. Aluminium can look sound on the outside while the strands under the jacket have already gone chalky and brittle.

Tape or cap an open end before the reel goes back into the yard. It takes a minute and it protects the part of the cable a buyer examines first.

What a buyer looks at, metal by metal

Conductor material gets confirmed early, from the tag, the jacket print or the cut end. From there the questions split. On copper the interest is size, strand condition and whether the exposed ends are bright or corroded. On aluminium it is oxide, water damage, and whether the cable was ever installed and re-terminated at the far end.

Value per pound is a different conversation from value per foot, and neither is the whole story here. Copper usually carries more per pound. Aluminium lots are often larger, which can make a single collection worth arranging where a copper lot of the same total weight would not be. The two metals are reviewed separately even when they travel on the same truck.

Colour and jacket material matter less than the metal, but they are not irrelevant. A bare copper grounding conductor with bright strands is easy to place. The same conductor gone black at the end is a metal lot. Aluminium with the oxide scrubbed off one end and left alone on the other says something about how it was stored.

• Conductor material, confirmed at the cut end
• Size, conductor count and voltage class
• Bright copper or chalky aluminium at exposed strands
• Water in the end, and whether it was ever sealed
• Terminations cut back, or still fitted to the cable

There is no rule that a mixed metal lot has to be split. It does have to be described, because averaging copper and aluminium into one figure misleads in both directions.