Interesting topic considering it does reduce down to connecting three wires more or less. The executive overview is that hopefully the inverter, circuit breaker panel and GFCI will come with good instructions on how they need to be wired.
At least some of the GFCI are recommended for use in two wire only retrofits. The requirement is that somewhere at the power source there is a ground. These units may come with a sticker saying "non grounded outlet". The test button still works since it jumpers over the sensing circuitry from hot to neutral, no EGC required. Maybe this will explain it a lot better: https://www.nema.org/Products/Documents/NEMA-GFCI-2012-Field-Representative-Presentation.pdf Check out page 14. A point I was commenting on was that even with a correctly wired AC system, EGC and earth ground bonded together at the correct location and everything to spec a person can still get electrocuted. It is a safety requirement though more so to help the utility with lightning strikes and to ensure the OCPD ( circuit breaker ) trips if a load shorts out. Tongue in cheek was the comment that the ground path is likely the current return if a person gets a shock. If there is a problem with the earth ground even a GFCI may not help. In a marina or club if all the grounds are correctly tied together a persons safety is dependent on the quality of the worst installation using shore power. Michael Brown Windburn C&C 30-1 From: Josh Muckley <muckl...@gmail.com> "So if the inverter is floating and has no ground you cannot get a ground fault shock. If there is a ground wired in you could get a shock but the GFCI should trip. Maybe having the GFCI in is a good thing in that if there was a defect in the load you would never know it without a ground. With it the GFCI would keep tripping letting you know something is wrong." Michael, As you stated the GFCI is comparing the current on both the hot and neutral. When a difference is sensed it trips the GFCI. You mentioned that without a ground the GFCI won't trip. 2 thoughts come to mind. First, without a ground, the GFCI won't trip during a "test". The pushbutton connects a high resistance to the ground prong creating a leak path for current so in that case you're completely right the GFCI won't trip. Second, the GFCI is still sensitive to a difference in current between hot and neutral. You can wire a GFCI ungrounded and it will still trip during a fault. You need a leak path. Most GFCI outlets are sensitive to 5mA. The idea that the inverter is using an ungrounded system and as a result, you won't trip the GFCI sounds synonymous with the idea that since I'm wearing rubber shoes, standing on carpet, in a wood frame house I won't get shocked by the hot. I can tell you from experience, you will get shocked! All of this discussion about floating AC actually gets me thinking about whether or not the GFCI outlet has a disconnect on both the hot and neutral lines. Even if the GFCI trips the neutral prong may still be connected to the neutral wire which in a home isn't a problem, but with a floating AC system you could still be exposed to voltage. We had problems similar to this while on Navy ships. The crew had bought generic computer surge protectors which all needed replaced with high dollar ones since the generic ones only protect the hot terminal. Josh Muckley S/V Sea Hawk 1989 C&C 37+ Solomons, MD
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