Suggestions for new wiring
I would suggest that care is used to select materials for project. A wire called mtw, read machine tool wire, is terrific for most wiring, and is tranded. This wire is very common and available at most electrical stores and sign companys. The wiring from tow vehicle is not a long distance and Number 12 AWG will do a good job. If possible, after check to be assured all connections are correct, soldering is very good. The connections inside the quick electrical disconnect should have all the wire ends soldered before fastening with screw. The new can wire sleeving is good instead of lots of plastic tape to make a wire bundle for plug end. It is not necessary but different wire colors for different tasks is nice. Extra wire can be made into nice spare wire roll in trailer. Making a mechanical restraint for wire is required. Usually the ground wire will do this task well. I usually size the ground wire to # 8 AWG MTW with the ends crimped and soldered.
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