I bought a 30 foot long, 30 amp extension cord and cut an 18 foot section with the male end on this cord. I ran the cord along the top of the basement and into the front curb-side propane compartment. I made sure it was long enough so that the cord could hang through the opening in the bottom of the compartment and reach to the bed of the truck.
I added a new male end to the leftover 12 feet of the extension cord. This short cord is always connected to the generator and runs to the rear of the pickup bed.
For obvious reasons, you don't want an energized male plug anywhere, especially in the propane compartment. So it was time to do some electrical fabricating. I came up with this transfer switch with a manual interlock. I used a 100 amp add-on panel with a couple of breakers. About $35 total for these. After removing the basement wall, I figured out a place to mount the box where it would be accessible.
The 50 amp cable from the rear service connect is connected to the output side of the 50 amp breaker (top one). The cable from the 30 amp service connect at the front of the trailer is connected to the output side of the 30 amp breaker. Also, a jumper was used across the 30 amp breaker so that both legs would get 110 volts from the front service.
The wiring hooked to the main lugs in this add-on panel runs to the Progressive EMS. So the trailer's electrical is protected regardless of which service (rear 50 amp or front 30 amp) is used.
Here's a picture of the Progressive EMS.
The real function of the breakers is to serve as switches. But there's no way they should EVER both be on at the same time. That would mean an energized male connector at one end of the trailer or the other. I also needed to make sure that the two legs of the panel would not be connected together when connected with the rear 50 amp cord. That would result in 220 volts throughout the trailer and a bunch of fried equipment.
The solution to this problem is what is known as an "interlock". Only one breaker can be switched on at a time with this interlock installed. These can be bought for some small breaker panels (i.e., Square D Homeline panels), but I decided to fabricate my own using 1/8" thick aluminum plate. It took some experimenting to get the dimensions right so that turning one breaker on will reliably turn the other one off.
Add an access panel to the basement wall, and the job is done.
When we need to switch from using the rear or front service, the panel is easy to access in through the basement door.
We used this setup a lot during our 10 week trip to Alaska this summer. Whether boondocking or camping at parks with no electric hookups, it was nice to be able to just drop the cord out the bottom of the propane compartment and hook up to the truck.
The front electrical hookup also came in handy at many campgrounds. Many only had 30 amp service and often the electrical service was closer to the front of the trailer than it was to the back. A spare 25 foot 30 amp cord came in handy as well.
Best of all, we didn't have to wrestle the "anaconda cord" when all that was available was 20 or 30 amp service!
