Making your own trailor cable......

[JSGOLD]

I need to rewire my trailor to correct a ground issue and update as the old wiring was not done using correct size or color as well. I was wondering if any of you had ever used THHN building wire and made your own cable. I have access to whatever I need as I work for an electrical distributor and THHN is rated for 600 volts and has a protective nylon coating on it. Rather than the trailor cable "kits" I was looking at using 14 guage stranded conductors with correct colors, an extra 12 guage white cable going directly to the cable to eliminate ground issues, and split duct for added protection. Still unsure whether to solder connections and heat shrink or use w/p crimps and heat shrink. Any thoughts appreciated!

 

[wifisher]

Re: Making your own trailor cable......

I have done almost exactly that in the past. Had to get a trailer on the road, and THHN was all I has on hand. Only difference is I ran most of it through conduit (welded to frame). The trailer I did it to lasted for 5 years before we got rid of it and had no problems.
I always run a ground wire, as frame/body grounds seem to have too much trouble.
As far as solder/crimp, I like to solder because it actually connects the wires, and eliminates the chance for connector related problems. I know a lot of people like the crimp connectors. Whatever float your boat.

 

[Silverbullet555]

Re: Making your own trailor cable......

I would ask what the advantage to you is to making your own? The premade kits are pretty cheap so cost really isn't a factor. That being said, if you are doing something special, then making your own can make sense.

For instance, I am rebuilding my trailer this year and moving from a 4 flat to a 7 round. This will allow me to be prepped for going from drum brakes to disc brakes with the rever solenoid. also, I am adding LEDs under the trailer to light it up if I need to work in the dark. the aux power wire on the 7 round can be used for this as it is always hot and the LED will be switch operated.

If you are not doing anything special, I would just go with a 4 or 5 flat kit as it will be easier. I did that on our last boat when I rewired the trailer after our boxer ate all the wiring from underneath.

 

[JSGOLD]

Re: Making your own trailor cable......

The two reasons are that I want a direct ground included to each light and cost. I can get the THHN wire cheaper than the kit. Plus, the kits looks wastefull to me. I have never installed one but it looks like you have to run all the wires on both sides.....or do you just split the cable in two?

 

[LippCJ7]

Re: Making your own trailor cable......

I don't think it can hurt anything, if I remember correctly the THHN coating is intended for chemical protection and has zero UV benefits, in my experience with THHN it will likely just come off after a couple months anyway leaving the PVC coating and then your no worse off anyway. We use THHN in communications enclosures for Battery power but anytime we run it outside it has to be in PVC conduit to protect it from sunlight.

 

[soldier side]

Re: Making your own trailor cable......

I've been doing automotive/trailer wiring for 10 years, and my advice is to get the wiring harness at walmart (only $10), starting at the front, cut off your white wire (ground) and drill a pilot whole in the botom of the trailer tongue and screw the ground there, split your other 4 wires (2 on the left, 2 on the right) and then run them back to your tail/brake lights, these are all 4 hots (running lights, turn signals, and break lights), you're light housings should have build in grounds via the mounting bolts, mount them into the metal on the trailer and you have a full ground/hot circuit. this is the most effective way to wire trailer lights.

As a side note, no wiring method is permenant and should be inspected every 3-6 months ( not the include every time you hook up your trailer), and replace every 2-4 years or as needed.

good luck