HI Everyone - I have a 1980 410 Commander. We got new docks this spring. The new electrical code apparently requires a more sensitive ground-fault system and as a result the boat will pop the breakers on the dock if I plug in both 30-A cords and set the switch in the boat to "Both Inlets" I can use one cord and "Inlet 1" on the switch and that works fine (except of course I only have 30 amps to work with).. I'm told that "somewhere" the neutrals from both sides are connected. They are not supposed be. Anyone had this problem?
I found on my 410 that the FB and the rear deck outlets were wired - hot to one 30 amp feed and the neutral to the other 30 amp feed - BIG no no . I thought this was a build error on my boat, but maybe not . Any way I made mine right .
Here's an update! Inlet 1 continues to work ok. Changing the selector switch to "Both Inlets" produces good results (everything works) except: 1. Turing on the inverter 2. Turning on one of the two Air conditioner/Heat units and 3. Turning on one of the two lights in the engine room. By "turning on" I mean switching the breaker on the panel in the boat to "on"for that circuit. When these breakers are turned on both circuit breakers on the pedestal on the dock pop.
The inverter powers the refrigerator, microwave, lights and some outlets. It charges the batteries - dedicated for the inverter - and will pass thru AC to the appliances if AC is available.
I would try completely disconnecting the inverter from the 120VAC. The inverter 120VAC present sense circuit might be the problem. You might have other issues also such as the problem light in the engine room.
The AC unit that causes a trip might also have an issue with its control. Not necessarily a wiring issue but a design feature that improperly allows leakage current onto the boat ground system.
The underlying issue is that the new NEC code requirements have reduced the GFCI trip current to 30ma. A 4000 ohm resistance or impedance is enough at 120VAC to cause a trip.
Not splitting the inverter neutrals off separate from the remainder is known to trip the dock side GFIs. I had found this recommendation online and a respected marine electrician I know confirmed this is a common problem for boats with inverters installed. When I installed my inverter I was able to separate the neutrals easily by adding a third neutral bus bar to the panel.
Here is the link to the article:
Doug Maclean said:
google " marina safety upgrades " boatus Char - it would be good info for the library