Wiring Woes

3 Wires Fused to Converter NEG Lug

After much effort, trouble, and a few bruises, I have learned some things about my wiring in the van house.  This all started with a blown fuse that blew and sparked every time I replaced it.  The van had blown both the converter and inverter before I bought it.  The dealer had replaced both and spliced a fried wire to the inverter neg.  It worked fine last summer after I bought it but for some reason, it blew fuses during the fall.


I started by checking the fuses and noticed that 3 of them sparked while the rest did not.  In addition, the 30 amp main fuses also sparked.  I opened up the fuse block at the fuse block in the converter housing and found 3 wires with their insulation burned thru and fused to the Battery NEG lug.  That certainly explains why the sparking and shorting.  But then the question is:  why is that lug and wire so hot that insulated wires melt and fuse to it?

Converter NEG wire with the damaged insulation

The wiring was a terribly tangled mess.  I spent a fair amount of time tracing wires, disconnecting, untangling, then reconnecting and labeling every wire I could figure out where it went to.  After I got them untangled, at least to a common point, I methodically tied each bundle with wire ties so they are neat and tidy.  The cavity sure looks a lot better now and there will be no more running wires in between those in a bundle.  I had a career in computers and I don't understand why all people don't do good wire management, including labeling them.  It is so hard to figure out what goes to what without labels.  It is important in computers and important in any electrical job.

In addition, there are lots of black wires that go back to the battery positive.  I wrapped as many as I could figure out with red electrical tape so I can tell the positive wires from the negative.  I found a short cable that went to a ground wire  but unconnected on the other end.  I don't know if something is missing a ground or if
it was sloppily left there when they replaced the converter and inverter.

This is how I found the wiring behind the Converter

This is after I spent hours untangling the wires and tying the bundles with wire ties

I get sparking when I try to connect the main battery positive cable to the battery too.  I tested the 3 wires that connect directly to the battery positive lug.  I have the problem narrowed down to the big battery cables that go to the inverter.  So somewhere in that circuit, there must be a bad connection in that set of cables.  To fix the problem before I took possession of the van, they put a splice in the battery negative to inverter cable.  It goes to a junction box underneath the van joining to the long battery negative cable and another cable.  I decided it should be replaced with a new, intact cable.  Sometimes, DC cables can cause problems when there isn't a visible problem.

I still haven't found where there is a positive wire going to ground to explain the hot wires but at least I can fix the obvious problems and go on from there.  I now can follow more of the wiring in hopes that I can find it.