Busbar Updates

The new SolarAPP software version 3.0 will bring changes to how electrical layouts are described to the code compliance system. The permit form will now work with a single busbar prototype which will support a Main Service Panel, a new panel board for relocated loads, a combiner panel for the generation sources and more.

You will need to provide SolarAPP the information about all busbars, new or existing, that are affected by the work being submitted for permit. The first new input you might notice is the one asking for the busbar quantity:

The Main Service Panel or an existing load center might be affected by the back feed current from the generation sources, additionally you will need to provide supporting information for all new busbars, such as combiner panels or load centers for relocated loads.

Pro tip: When in doubt, you may find information bubbles next to the inputs useful, this one below might help you understand the "busbar" concept ahead of the examples below.

Below you'll find some example videos for common use cases on PV projects, the videos are accompanied by a simplified block diagram describing the electrical layout in the example. The location of the PV inverter and PV combiner panel is represented by the circle in magenta.

Direct connection at Main Service Panel:

Supply side connection at the service feeders:

Connection at Existing Subpanel:

Load side tap on a Subpanel feeder:

Subpanel Insert or New Subpanel for Relocated Loads:

A main lug only panel is a busbar that contains no Main Breaker and instead has one or multiple service disconnects. A service breaker enclosure can refer to a meter disconnect switch in accordance with NEC 2020 [230.85]. Some panels may not have a bussing and rely on field or factory installed conductors, in which case the ampacity rating of the conductor should be used as the busbar rating in this application. An existing Main Service Panel may be permitted as a "Main Lug Only Panel" in accordance with the applicable code.

To all of the above, you could also add a PV combiner panel if necessary:

The inspection Checklist will group the checks for all of the busbars in the permit, as in this Subpanel Insert example: