R736 Error Tutorial 1a: Interconnection Location for Sources, PV+ST

Understanding the Issue

One of the most common errors is identifying the point of interconnection (POI) for sources and systems.  Each inverter and ESS shall locate the first point of interconnection, naming either the busbar or conductor where the source output and house loads interact. Sometimes this is achieved with a breaker in a panel; however, for projects with a backup load panel, the backup initiation device (BID) acts as a load side interconnect to the conductors feeding the backup loads subpanel.  The Tesla Backup Gateway in the image below shows how it is connected to the subpanel feeders at its terminal lugs.

Troubleshooting Steps

1. Review the Upper Electrical Section: Ensure the correct interconnection location is selected for the inverter, energy storage system, and combiner panel.
   1. Question: Where will Inverter 1 be interconnected?
   2. Recommended Answer: Subpanel feeders
2. Check AC Energy Storage Systems: If an AC Energy Storage Unit is present, verify that a similar question in the upper-middle section is correctly answered.

3. Lower Electrical Section Adjustment:
   1. Question: Are you connecting your power production sources to the feeders of busbar #2?
      1. Recommended Answer: Yes
   2. Review the article on the Breaker Sandwich method of interconnection
4. Validate with Diagrams: Refer to your system diagrams and confirm that the inputs match.  SolarAPP will be confused if you call out the interconnection location as an existing subpanel if you haven’t detailed an existing subpanel.

Additional Tips:

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