Trailer wiring

​I will say here that I am a cabinet maker, not and electrician, or any kind of engineer, for that matter. 
  Some things were questionable on the wiring for my trailer. Something had blown the 12 volt fuse so nothing was working. I questioned weather the old convertor was in working order as well. Re wiring should have been a couple week project, even for a novice, I think. But really, I know nothing, so I embarked on a "learning journey" about trailer wiring. This took me a couple months, so it has slowed me down a good bit as I am trying to get this thing rolling by next summer, 2017.
  I'll share what I learned with you here.

  First I have a friend who is helping me some, and Dave in an electrical engineer. He has been calculating loads and such, and going over the breakers in the 110 box. It appears that some have been changed for wrong loads, over the years. We are correcting that. The next thing I did was purchase an Inteli- power. Model PD9245C rated 45 amp. Along with that I got a 12 volt fuse box. I'll put up pictures a little later. 

 So here's the deal, Trailers have three systems. 
The first system is the 12 volt from the pig tail in the tow vehicle bumper. This system is completely separate from any other trailer wiring. It goes only to the outside trailer lights, (tail lights, marker lights, and the power brakes). It runs down inside the street side wall along with other wiring, but is hooked up to none of that. It comes in at the front wall above the trailer hitch, down at the floor. There shoule be a little door to access it.

 I found, on mine, that on a lot of it, the insulation had melted together, so I replaced it all with new, high heat, auto wire. (14 gauge stranded wire.) I got colors to match the existing wiring from the truck 7 prong plug. This was existing in the trailer too. Not difficult at all to replace. 

The second system is the 110 volt shore power. It starts with a cord to the shore power poll at a camp ground. That comes in and goes to the breaker box and then supplies all the 110 plugs in the trailer along with the Air conditioner, and the Refrigerator which plugs into a plug behind it. That was all in good working order and I opted to keep the romex wire that came with the trailer. It installs into the plugs better/ tighter than stranded. I also made the couple switch legs from lights with 14gauge romex. .                                                                                                                           
The last system is the 12 volt system, mostly for lighting. This starts with the convertor, which plugs into a normal 110 volt plug next to the convertor location. This is the only place the two systems come in contact with each other.The convertor has heavy ground wires to it and then heavy wire, like #6, to the battery, for recharging. It is then hooked to the 12 volt fuse box. All circuits of the 12 volt start there at the fuse. They all go the lights, and any other  12 volt locations. Usually the heater needs 12 volt for the ignition, The ref. needs it too, along with the water pump, the toilet vent, the hot water heater, the radio, some gauges maybe. A number of things like that.  Since I wanted to  add a couple lights down the center of the trailer ceiling, a shower light, a rear outside light, a porch light, a radio hook up, and new lights under the front overhead cabinet , I chose to replace the original 14 gauge romex 12 volt with the 14 gauge stranded. I was advised along the way that would be the best thing to do. The stranded hooks up to the stranded wire in the lights better than a solid wire, I think. I made 6 different circuits going to all of these components. Each kind of circuit got a different color hot wire along with a black ground.  I had the wire because I bought 250 foot rolls of the colors for the outside light circuit. This cost about $180  and I have used all 250 feet of the black wire, a good bit of the red, which I user for both of the light circuits. I have two Fantastic vent fans, and a stove hood vent fan and a vintage 12 volt fan just to move air around the cabin. I did two circuits for the fans, two for lights and a couple more for other things.    
      So there is my summery of trailer wiring. This could be of help for some of you, but then maybe you all know more than I did to start with, which was next to nothing. Ill add some pictures later. 

It's the middle of March now and I have just gotten back to work on the trailer since late October when I put the trailer back in storage. 

I had most of the wiring done then and I'm now finished with stringing wire. I'll clean up everything and start checking circuits this weekend. It's taken way too long to do this phase. I'm having to learn as I go and I'm not an electrician. When I get stuff checked out I'll re-apply the insulation and start cleaning the inside aluminum so it can be riveted back in place.
I'm doing a tentative hook up mostly to keep track of things as I work. I'll make a PVC tunnel to bring all of that wire out of the wall and move the box and buss bar around to work right, when I get there.
Got with my buddy, Dave, this weekend and we did testing on all of the wiring. Installed switches,Lights, did some safety work in the 110 box. Now I'm free to install insulation and cover everything up.
When I got the trailer the 110 was working but needed several repairs. the 12 volt was not working at all. I found a blown fuse later that had caused that problem. Some of the wire down the street side had the insulation melted together from too much heat. Just high temps in the summer or a short causing the wire to get hot.??? But it's all corrected now. So moving on. I am extremely happy to get to this point. The wiring has taken me months. I had so much to learn and think about, and still, I needed help from Dave to finish and test. It's just not my thing.
A little addition to the wiring saga. A friend of mine, Eddie Huffstetter here in Houston is a big Silver Streak and Streamline guy, offered to help me wire in a switch to turn on all the running lights when in a camp site and not hooked up to the truck. I got him to come over one Saturday, thinking it would just take a couple hours maybe. He took one look at the wiring coming from the  truck, and said, this is all wrong. (Stuff done by previously owners). So we started in sorting wiring and about 10: 30 that night we had most of the work done. Working with a flash light mostly.
He came back on Sunday and we wired in the switch but the brakes still wouldn't work ( they weren't working when I got it). a couple hours later we found a brake in the wire going back to the brakes. Fixed it and all good. Eddie worked with me on the problem for 10 hours. Thanks so much.