I wanted to inquire, whether it would be recommended to feed the Grid-Tied PV system back in the electrical panel which are either backed-up by emergency generator or panel receiving stepped down voltage from a higher voltage source.

Our facility has 1200A, 3-phase, 575V, electrical system. Lighting and other standard 120/208V electrical services are provided via step-down transformer(s) further downstream in the electrical system. The facility also has a 70kW, 3-phase, 575V, emergency generator.

Based on our evaluation, it may be feasible to install a 3 kW, 3-phase, 208V, 10-panel, Grid-Tied, micro-inverter based, PV System in the facility. We need to provide a 20A,3-Pole breaker in one of the 120/208V electrical panel which connects to the PV system. I have the following queries on the two (2) scenarios:

1. Install 20A, 3-Pole breaker in a generator backed electrical panel
- Is it recommended to install such a PV system in a generator backed panel?
- During a power outage, the PV system should de-activate because it is mirco-inverter based. But if the panel is backed up by the generator and is energized during a power outage, would it be a safety concern as the PV system installation i.e. would be be re-energized?

2. Install 20A, 3-Pole breaker in the 120/208V electrical panel which receives stepped-down voltage from 575V system
- Is it recommended to install such a PV system in an electrical panel which recives stepped-down voltage?
- Some step-down transformer manufacturers do not recommend feed back into the transformer, so would connecting a PV system be a safety issue or lead to void of any standards ratings?

I'd appreciate your comments or suggestions on this issue.

Thank you.