Some thoughts about building a three phase system with multiplus 2 with off grid capability. Is there some way of confirming the connection to earth when in off grid (the multi disconnects L and N on AC in, correct?)
Seeing as I don’t want to risk sending a current back to the grid from the multi when using battery power, I cannot connect the AC out to the grids neutral or PEN. When in off grid mode the idea is to use a grounding rod as the neutral point and earth (effectively creating a TN-C from the multis when in off grid)?
How do I eliminate the risk of losing my neutral point (connection to earthrod is lost somehow, or the resistance to earth is to high) and thereby risking damaging electronics connected if the loads are uneven over the three phases (0-400V on regular outlets)?
Has anyone experienced problems with this? Is there some kind of module that could be installed that measures the ground resistance continuously and breaks the AC out if ground is lost?