Are Optronics 35 Ft 4-Way Trailer Wiring Harness Wires Solid Copper

Updated 02/27/2026 | Published 02/24/2026

Question:

I am wondering if the wire in this wire harness is solid copper or is it copper coted aluminum wire thanks Brian

asked by: Brian K

Expert Reply:

Hi Brian; the 20 AWG wire on the 35 Ft 4-Way Trailer Wiring Harness # A35W42B is solid copper.

What kind of trailer do you have?

expert reply by: Robin H

Trailer Wiring Harness
(click to enlarge)

Brian K.

2/26/2026

I'm asking if these wires are solid copper or if they are aluminum wires coted with copper. SOLID Copper wire lasts ffor a long time and aluminum wiring coted with copper will oxidize and literally turn in to powder @ 10 years of water infiltrating a small Crack in the wire but you are the expert so you should know why I ask this about the wire and not about a trailer that has no name (home built trailer) thanks for tour help Brian

Robin H.

2/27/2026

@BrianK like I said above, it’s solid copper not copper-clad aluminum. If it were CCA I would have said that. I understand why you’re asking, which is why I answered it directly the first time. The trailer question wasn’t avoiding anything, application can matter when recommending wiring.