I woke up at 3 AM thinking about this and what could be done to help out. So I went out to the caboose and brought in a few things and tried to make a simple mock up of how the outlets and switches work.
So this is my attempt to untangle the AC side of tiny trailer building.
A few small sections of romex
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pealed back and the ground paper removed
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For this example I removed the outer sheath so you could better see the colors and understand the path of the electricity.
Here are the parts
a fuzzy picture of a duplex outlet.
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The thing to note here is that there are silver and gold screws and a green one. Gold is hot silver is not and green is ground is a good way to remember the color scheme.
The ground and the neutral (white) continue on and on from fixture to fixture only the black is interupted with switches.
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note there are only 2 GOLD screws on the switch indicating black or (hot) wires.
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Take a stripper tool and remove about 3/4 inch of insulation
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You can check its length by a stripping gage on the back of most outlets
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ground crimps and wire nuts are a must have
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A side note duplex outlets most often are cheaper by the contractor pack
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I started with a short section of 12-2 extention cord with ground and added it to these duplex outlets
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with most stranded wire it is best to use the forked crimp connectors to make a neat connection.
Here I have added a light bar and a switch note all the white and ground wires "play thru" and ONLY the hot is interupted with the switchs
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The light bar has a little screw fitting marked grd for ground. (I have lost the screw for this one ) see the box!
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Here we have flipped everything over and powered up the little jug lamp and fan are both working
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and with a flip of the switch
I have used the simple pig tail just like shown above for the power connection to most of my trailers. I have relied on the campground for the safety breakers however there are several "smart" extention cords that have GFI and Surge protection built into them.
I hope this simple experiment helps to clear up some of the mystery about wiring AC
