GFCI outlets compare current in the hot and neutral and trip if it is not the same. If an inverter has no connection at all to ground, i.e. a floating AC system, connecting either hot or neutral to ground would have no effect and not trip the ground fault. You could, in theory, sit neck deep in water and hold onto one of the AC wires and not feel a thing. (DO NOT TRY AT HOME) The reason shore power works with GCFI outlets is the neutral and ground are connected. If you come into contact with a hot wire and your body is grounded at all, the current will flow out the hot, through you, and back to ground via some other means than the neutral wire. The ground fault senses this and trips. Likewise leaks and shorts to a grounded piece of equipment would trip it. Do note you can still kill yourself by grabbing hot and neutral. I have a 300 watt and 1000 watt inverter and can switch between them. Either one will trip the ground faults if tested, so they both connect the AC side to ground somehow back through the DC negative connection. I need to go test them and see exactly how. It could be the standard neutral to ground connection or it could be something goofy like the power transistors being grounded at a center point and each side of the AC circuit is on one side of a center ground. Just an FYI, am 99% sure commercial ships got away from grounding issues and use floating AC.
Joe Coquina C&C 35 MK I From: CnC-List [mailto:cnc-list-boun...@cnc-list.com] On Behalf Of Tortuga via CnC-List Sent: Monday, October 24, 2016 15:49 To: cnc-list@cnc-list.com Cc: Tortuga <tortugas...@gmail.com> Subject: Re: Stus-List Inverter to Outlet Via Extension Cord? "Similarly with an inverter connected to a battery that is not grounded a GFCI should never trip. Theoretically in a floating system the power has to come out of the Hot lead and return in the Neutral. There will never be a ground fault to trip a GFCI. There is no ground." I'm not an electrician, but my limited understanding is that a Ground Fault Circuit Interrupter monitors the hot and neutral leads and interrupts the circuit almost instantly if it detects a difference between them. The ground lead does not come into it. The Xantrex Freedom HF 1000 that I mentioned in an earlier post is UL458-listed. "The two UL standards differ in how they handle AC system grounding: UL1741-listed inverters must allow for the neutral-to-ground bond to only occur at the main AC service panel. UL458-listed inverters have internal neutral-to-ground switching relays to allow for this bond to occur at the inverter if in off-grid mode, OR at the utility power service if it is connected to a utility hookup." Perhaps I'm missing something. Derek Kennedy SV Tortuga, 30 mk1 Ballantyne's Cove, NS
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