Does The 25 Ft 4-Way Trailer Wiring Harness Have Tinned Copper Wire?

Updated 10/30/2026 | Published 10/28/2026

Question:

Is the copper wire tinned?

asked by: John

Expert Reply:

Hey John, thanks for reaching out. No, the Optronics 4-Way Wishbone Trailer Wiring Harness # A25W2GWB uses bare copper wire rather than tinned copper. That said, Optronics makes dependable trailer wiring products, and this harness will work just fine on really any trailer as long as the connections are properly sealed and protected from moisture. I recommend using heat-shrink butt connectors and dielectric grease to help prevent corrosion, especially if you're installing it on a boat trailer.

What kind of trailer are you servicing?

expert reply by: Jesse M

25 Ft 4-Way Trailer Wiring Harness - Wishbone Style - 25' Ground
(click to enlarge)

Jordan S.

10/29/2026

I’ve used this harness many times for my boat trailers. I solder and heat shrink the connections and I’ve never had an issue. Far better than relying on the trailer to be your ground

Jesse M.

10/29/2026

@JordanS Yep definitely a good call with the heat shrink. Thanks for sharing!

Jordan S.

10/29/2026

@JesseM I trailer my flats boat a couple thousand miles a year, and I recommend this harness to all my buddies.

Jesse M.

10/29/2026

@JordanS Nice! I appreciate the recommendation!

See All (4) Replies to Jordan S. ∨

Mike N.

10/29/2026

Hi, I use this wishbone trailer wiring harness on a 2016 Bass Tracker boat trailer and it’s working like it came from the factory. The copper wire is not tinned. Etrailers sells reputable replacement wiring but do your research to make sure your getting the right wiring harness you need. Gone fishing. Later.