HoosierSparky
Senior Plans Examiner, MEP
- Location
- Scottsdale AZ
- Occupation
- Senior Plans Examiner
We have an area of town that used to be citrus orchards and have 3 phase open delta (240/120) services to homes. 3 phase was used for irrigation pumps. The older homes have delta breakers for their A/C units in single phase panels. Updated services have 3 phase panels with the high-leg breaker spaces skipped, except for the A/C units.
I am seeing an uptick in PV being installed and they are using single phase inverters. EVERYTHING on my side of the service (homeowner side) is to code or better. I am concerned about the other side. I do not see issues with only a few single phase PV backfeeding a 3phase service. My issue is with a lot of these connecting creating an imbalance. Due to the type of inverters used, they are connecting 3-wire (2 hots, one neutral). Also, being open delta, the high-leg transformer is smaller.
I have pointed this out to the local POCO's that serve this area. For some reason, they had not considered this issue before, due to the low number of PV systems being installed there. That has now changed.
Am I overthinking this?
I am seeing an uptick in PV being installed and they are using single phase inverters. EVERYTHING on my side of the service (homeowner side) is to code or better. I am concerned about the other side. I do not see issues with only a few single phase PV backfeeding a 3phase service. My issue is with a lot of these connecting creating an imbalance. Due to the type of inverters used, they are connecting 3-wire (2 hots, one neutral). Also, being open delta, the high-leg transformer is smaller.
I have pointed this out to the local POCO's that serve this area. For some reason, they had not considered this issue before, due to the low number of PV systems being installed there. That has now changed.
Am I overthinking this?