Originally Posted by peikenberry
40 or more years ago it was quite common to find boats (and cars) with positive grounds. In other words everything was reversed. But today polarity is a very important issue. In other words maintaining positive and negative are hooked up correctly. So, now all boats are negative ground and switches and fuses are in the positive wire. I would switch it, but before I did, I would make sure polarity is maintained throughout the system. In other words positive is hooked to positive throughout.
FWIW, the main reason cars and boats were once wired for "positive grounding" (really "negative switching") and about its only advantage was that, wired in this way, it was possible to use a cute little 12V test-bulb to test for continuity at all points in the circuit up to the point of the final switch, making fault-finding relatively easy in the days before cheap Chinese-made multimeters.
Nowadays, the disadvantages outweight the advantages. If it were me, I'd change it.
From RFC 1925: "(3) With sufficient thrust, pigs fly just fine. However, this is not necessarily a good idea. It is hard to be sure where they are going to land, and it could be dangerous sitting under them as they fly overhead."
Last edited by Classic30; 05-30-2011 at 02:13 AM.