I've recently installed a Xantrex XC 2000 Purse Sine Inverter Charger. I placed the unit in the aft cabin hanging locker and wired to battery one - Which i plan on combining with battery 2 and make a house battery when i add a strarting battery. The size of DC cables for the inverter was 2/0 awg and 1/0awg for the chassis ground. I ran the chassic ground back to the ground bus bar behind the chart table electrical panel. My question is with reference to the wire size of the DC Negative bus bar. It seems like the cable coming to that bus bar is probably 4-6 awg and I've connected a 1/0awg cable to this bus. Should I add a second dedicated bus for this install and pip tail another bus to accododate the inverter? I also have an electric flush toilet on a long run that comes back to the same negative ground bus.
Thanks,
Samuel
C36MKii
#2036
Samuel Cummings
Catalina 36 MKII - El Dorado II
Hull #2236
According to ABYC specifications, the chassis ground connector should be the same size as the current-carrying DC cables that supply power to the inverter. That suggests that the entire chassis ground path all the way to the battery negative has a similar capacity. Very few installations follow this practice. It's there to prevent a +12v-to-chassis short from becoming something worse than just a blown fuse.
I've seen folks use a big chassis conductor, but then just connect it to the negative terminal of the inverter. I'm not sure if this violates ABYC. If mainesail is monitoring this, perhaps he can chime in.
Nick Caballero
Retired C36/375IA Mk II Technical Editor
Chassis ground can be no more than one wire GA size below the DC wires. So if the DC wires are 2/0 then the chassis ground can be no smaller than 1/0. For 2/0 wire on a 2 kW inverter the entire DC circuit needs to be less than 10 total feet or a maximum 5' for positive and max 5' for negative otherwise 4/0 should be used.
Connecting the chassis ground to the neg stud on the inverter is not ABYC complaint.
-Maine Sail
https://www.marinehowto.com/