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Ground loop in AutoTransformer

Autotransformer schematics with Quattro/Multiplus state the following:

  • Inverter case ground should be connected to negative DC bus bar
  • Autotransformer case ground also needs to be connected to DC bus bar.

Also, in case of ac coupled PV setup, ground will get connected to Quattro (as grid input) - this goes to AC ground bus in main breaker panel. Autotransformer schematics also show the ground from AutoTransformer output connected to main breaker panel.

So, it seems to me that there is a ground loop if we connect the autotransformer ground to main breaker panel via AC out.

Is this correct?

So AutoTransformer output ground should not be connected to main breaker panel?

I have drawn the ground loop schematics below. Will appreciate feedback if I understood this right.


MultiPlus Quattro Inverter ChargerGroundingAutotransformer
2 |3000

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