Does SolarAPP+ include a system design diagram?

SolarAPP+ has introduced a schematic diagram of the electrical system in the checklist. The diagram allows the inspector and contractor to obtain a quick understanding of the layout of the system and is based on the information providing by the contractor when submitting the design. An example is provided in the diagram below:

This diagram from left to right shows the main service panel is connected through an electric power meter to the utility grid. A back-up initiation device is installed with a new subpanel that has relocated loads connected as well as a combiner panel for solar and storage equipment. 

1. Overview of diagram icons

Many different icons will appear in the diagram depending on the design of the system. Below is a list of icons with their definition. For some icons, more information is provided under the icon, such as MSP (main service panel) or Subpanel. In addition, (N) refers to a new panel and (E) refers to an existing panel.

2. Diagram examples

In this section, we describe a range of different system designs that are permissible in SolarAPP+. These diagrams can also be used by contractors to review their own projects, what diagrams should be shown when they complete their projects in SolarAPP+, such that they can address any potential input errors.

·       Example 1: Supply Side Connection

In this example, the solar PV sources are combined in a PV combiner panel and the point of interconnection is through a supply side connection (i.e., connection with the wiring of the premises on the utility-side of the main service panel.)

·       Example 2: Load Side Tap with Large Feeder Size

This diagram is an example of a load side connection with large feeder size. The design includes a PV source interconnected to the feeder in between the main service panel and an existing subpanel (“load side tap”) without main breaker.

·       Example 3: Load Side Tap with Breaker Sandwich

Example 3 is an example of a load side tap with breaker sandwich as the existing subpanel has a main breaker. Two combiner panels are used, one for combining solar PV sources and one for combining storage sources. The PV and storage interconnects with the wiring of the premises through the backup lugs of the external backup initiation device. 

·       Example 4: Power Control System (PCS)

Example four is another example of a load side connection but in this case, a power control system is included to monitor all sources of supply to the feeder of the backup load center. Both subpanels are new and have relocated loads. The top right subpanel is the backup load panel while the bottom subpanel represents the non-backup loads. The solar and storage are connected directly to the backup lugs of the external backup initiation device.

·       Example 5: Backup switch on main lug only panel

In this example, a main lug only main service panel is connected to a utility meter with backup switch. The solar PV and storage are combined with a combiner panel.

Note: “PCS is required to monitor all sources of supply to the conductor being protected. ‘PCS’ will only be shown on the diagrams where the feeder itself is being protected; if only the busbar is being protected, no indication of ‘PCS’ will be visible on the diagrams.”