Here's the procedure, if anyone wants to try it. First, make a drawing of your bracing and decide where you want every wire to go. I am using 14-gage single-strand wire in a loose 1/4" inch diameter plastic shield. If you're using different wire, you may want to push silicone goo into the holes through your bracing after wires are inserted to reduce chafing from vibration.
When you build your side bracing, drill holes through it so you can run your elecrtical wires through those holes. Then glue your bracing to the interior plywood sidewalls. Finally, cut your pink foam insulation to fit between the bracing and glue it in.
Using your paper drawing, draw the wire routes directly on the foam insulation with a wide felt-tip pen. Be sure the wire routes match up with the holes you pre-drilled in the bracing. Then turn on your soldering gun, get it hot, and follow the felt-tip lines. The foam will sizzle away, and you can make the lines as deep as needed. I ran one wire per line, between 1/8" and 1/4" deep. The electrical pliers give you an idea of scale. See photo below:
Next take a look at the wiring in my left sidewall. The center run is wires for tail lights, These are on the left sidewall because the hole for the door on the right sidewall limits wire runs on the right side.
Because my design includes a flat top, I built the top with its bracing before I put the top on. That let me wire it just like the sides. As you look at this photo, up is the right side, down is the left side, the left side of the photo is the front of the trailer, and the right side of the photo is the back.
The wires at the top go to dome light and ceiling fan switches on the right side of the trailer next to the door. The 9" square vent is wired for the ceiling fan (a 25 CFM computer fan). The four wires going down the bottom of the photo left to right are for rear right and left clearance lights.
When I run a wire, I press it into the slot that I burned in the foam. You could add a piece of duct tape to hold it if needed. I put butcher paper over my trailer and drew where my wires ran so I didn't nail, rivet, or screw into them! Then I put 1/4" thick aluminized bubble wrap insulation over them before I put on the skin. This meant that my wires disappeared.
When I put the skin on the trailer, I drew where the wires were so I could protect them from damage. This worked so well that I didn't nick a wire.
I though four photos would show the process. There are more pictures in my personal album and still more on my new website <www.crocodiletear.com> if you're interested.
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