We follow the DOT trailer wiring standard for sizing conductors and enclose multi single conductors and cables in split wire loom or in blue tube conduit.
All floor penetration s are in pvc to blue tube compatible boxes or end fittings or run in the trailer frame when possible. All tubing is fastened every 18" using metal straps.
Only metal tie wraps are used if used at all. Terminations are onto insulated ring terminals to a screw or suitable capture terminals never open wire ends under screws.
We crimp all connections and use die lectric grease on all finished terminations and in the rear of all crimped wire ends.
We solder wire connections and certain terminals dePending on situation.
Please check out this approach on our site www.flyingtigertransport.com
hope this is helpful. The attachment shows what can happen to plastic inline connectors under stress.