some more electrical questions

[bullydogsmom]

Ok a couple of more electircal questions from the eletrically challenged.

1. How is the 12 volt system grounded? We have noticed that none of the 12 volt "things" Lights, bathroom fan, etc, are not individually grounded. So how are they grounded? harold saw no ground wires anywhere on the frame when he was replacing stuff under there.

2. We are replacing the univolt with a intellipower There is a large guage white wire and blue wire Where are these suppose to be attached too on the new intellipower.

Annette

[Lumatic]

There are 2 separate 12v systems. The running lights and the interior 12v system.
The running lights are grounded to the trailer skin and frame and and to theTow Vehicle through the 7 way connector. The interior 12v system (OEM Univolt) runs through the converter. It is grounded by the 110 outlet. Newer converters are grounded to the trailer frame. As I understand it, all the interior 12v circuits are closed circuits and are generally not grounded to earth. There are several points where there are grounds to the trailer however. The 72 Service Manual shows the bathroom exhaust fan, galley roof light, water pump and scare light grounded to the trailer skin/ frame.

Re: Intellipower

There are 2 ways to skin the cat. 1.The pos and neg heavy wires on the Intellipower connect to the fuse panel and the fuse panel is connected to the battery. 2. The Intellipower connects to the battery and then back to the fuse panel. I like #1 because it worked for me. I talked to someone who tried #2 and had problems, why I don't know. You can salvage the fuse panel from the Univolt or use a new one. There are lots of old threads on this. I know on the 9245 the 12v + and - cables connect to the bottom front of the unit.

[Excella CM]

The 12V system isn't grounded(no third wire) in the same sense that the 110V system is because there is no need, i.e. no safety issue. Twelve volt energy goes from the batteries via insulated wires to various accessories and then returns(some would argue it's the other way around) to the batteries via the common conductive metal of the trailer body and frame, just like in automobiles–saves wire, labor and weight. Dirty ground connections can give you electrical grief and many weird symptoms caused 'ground loops' back through other properly grounded equipment. You will have the telltale wire from the old univolt left over since there is no connection for it on the Intelli-Power . There are threads that tell you how to work around this too.