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cosecha asked

Grounding options for Phoenix 12/1200 VE.Direct Inverter with GFCI Outlet

The Phoenix 12/1200 VE.Direct has two options for grounding the earth wire; neutral floating and neutral connected to earth. Which one needs to be used, in order for the model with the GFCI outlet, to function correctly?

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Phoenix InverterGrounding
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2 Answers
Kevin Windrem avatar image
Kevin Windrem answered ·

Neutral must be connected to safety ground for the system to be safe and for the GFI to function properly. If that connection is not made externally like in the load distribution panel the the internal jumper must make that connection

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hjohnson avatar image hjohnson commented ·
Actually, the ground pin has no bearing on the operation of a gfci. GFCIs work purely based on monitoring the current differential between the hot and neutral. If it exceeds 5mA, they trip.


In fact, according to the NEC, a GFCI is the only permitted way to add a 3 prong outlet to a two wire AC circuit.

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hjohnson avatar image
hjohnson answered ·

It all comes down to how you are using it and how the rest of your system is wired. According to the electrical code there souls be one, and only one, connection between Neutral and Protective Earth in an electrical system. If you do not have one elsewhere in your system, then enable it. If you’re feeding a distribution panel that has them tied together, then don’t enable it.

The GFCI itself doesn’t depend on the ground pin. It works by monitoring for a current differential between the hot and neutral. However, if you do have a PE/Neutral bond elsewhere, it will trip the moment you plug in.

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Kevin Windrem avatar image Kevin Windrem commented ·
The GFI will trip if a neutral/ground connection exists DOWN STREAM of the GFI, but not if the connection is UP STREAM of the GFI. This upstream location for the neutral-ground connection is the proper place.


Since your inverter is the SOURCE of AC, that is probably the best place to make that critical connection.

Neutral is bonded to safety ground so that any fault that connects the hot side of the AC line to a chassis somewhere, there is place for the current to flow and trip the branch circuit breaker. Without this connection, chassis would end up at line level potential and potentially pose a shock risk.

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hjohnson avatar image hjohnson Kevin Windrem commented ·
It will only trip if both bondings are in place. Yes, the proper place is likely in the inverter, but if you’re using it to feed into something that’s already bonded, then you will have problems.
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