Once known as Hartley18
Join Date: Aug 2007
Location: Melbourne, Australia
Thanked 85 Times in 85 Posts
Rep Power: 11
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.
A bad day on a boat beats a good day in the office
Last edited by Classic30; 05-30-2011 at 01:13 AM.