I am using an inverter that internally bonds neutral and ground. It feeds a main panel via transfer switch (as required by code). Of course my main panel also bonds neutral and ground by code. The inverter manual gives the following justification:
NEUTRAL and GROUND are bonded inside the inverter to comply with the National Electric Code (NEC) requirement that any AC source must have a neutral to ground connection.
Is the manual correct on this point? I thought the main panel was supposed to be the sole point of G-N bonding? However, assuming I connect each inverter terminal to the correspondingly named one on the main panel -- as recommended by the manufacturer -- this creates ground currents. As shown in the following drawing, there are now two G-N bonding points, effectively making both conductors into a single conductor and therefore sharing the return path current).
I'm pretty sure that ground currents are not allowed except by utility companies. The idea being that grounds within a building need to be at the same voltage for safety reasons. What is the best way to avoid ground currents if the inverter and main panel both bond G-N?
Update It was suggested to just add another switch pole for N. This may work in some situations, but I'd prefer a more general solution. For example, we may not have multiple neutral wires everywhere, as in the following situation.
