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My question is similar to this question.

Let's say I bond a true sine DC to AC inverter's neutral wire to my subpanel's neutral (which is bonded to earth in my main panel).

I know most DC to AC inverters don't really generate a negative current for half the AC cycle. 85 V is alternately applied to both the hot and neutral leg.

What will happens if the 85 V energized leg is grounded?

Does a flow of current between my inverter AC outlet neutral and the ground will be observed? Can this damage the unit or will everything be fine and will the potential between the hot and neutral leg be as expected?

Schema

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Most inverters now these days have the FG or G connection as well as a neutral for internal ground fault protection. I am going to assume that the above circuit is simplified, because the normal isolation control circuit is not included in the drawing. Otherwise, the Neutral wire from the inverter would reference its potential to the Utility Neutral and ground. This is a standard affair with earth bonded neutral utility installation.

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It's not OK to back-drive your panels like you show without a specialized disconnect (called a "transfer switch"). Reason is, if you are driving power backwards, then the guy working on your pole during a blackout could get electrocuted. The power company does not trust you to shut off the main breaker first.

It's not safe, don't do it.

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    \$\begingroup\$ The sub panel is equipped with an interlock system that totally makes that impossible. The neutral wire is not interrupted thought, the interlock system is only bipolar (L1 and L2). Some panel have a three pole breaker, but not the one I bought. \$\endgroup\$
    – Seb
    Apr 15, 2021 at 22:19

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