My 12 Volt Mystery

Yesterday I got a chance to learn more about my 12 volt system here in the trailer. One day I would really like to have a superb 12 volt system. Complete with multiple batteries, solar panels, heavy duty converters and inverters, and hopefully the ability to actually run for a decent amount of time without the need for 110 volt power. Until that day, I have 12 volt lights and a couple of read outs with a single converter and no batteries.

As I was saying, I was up to my elbows in the mess of what remains of my limited 12 volt system all because my 50 amp converter finally kicked the bucket. No surprise though, it was the original converter that came with the Airstream and was on my list of things I know will fail sometime in the near future. The new one wasn't too bad. I was expecting it to be a lot more expensive. As you can see from my picture, it really looks like a power supply out of a computer. Which makes since seeing how they do the same thing. It even has an 80mm case fan on it. The new one also only weighed about a tenth of what the old one weighed; no exaggeration.

I had some problems installing it. I even called my dad who helped me out quite a bit. I was getting continuity between the positive and the negative wire in my fuse box, so naturally, when I plugged in the new converter, it didn't stay on long. I looked around the trailer for a short, sure that something had to happen that caused my old converter to die and created this continuity, but nothing. In the end I just started unhooking wires until the multimeter told me there was no more continuity between the positive and the negative wires that come from the converter. Once that was figured out, the converter powered up fine and all my lights worked again, but here is the complicated part. The positive lead gives me continuity to the ground (which my dad explained might be a positive ground system and seems plausible), but the negative also gives me continuity to the ground... yet they still don't give me continuity with each other. Which makes absolutely no since to me. How do two wires make a complete circuit with the ground, but not each other? I'll even be the first to admit, my understanding of electricity lacks considerably considering I'm kind of a geek and all.... but I know a little. I guess I don't know this though.

None the less, the new converter works and is in place, distributing power to my lights, a really well placed clock at the front of the trailer, and my tank level read outs.