Free solar line diagram builderSee it work before it’s built.
Modules
Inverter
Add
Main panel · bus / main
Power is flowing to the house
Best on a tablet or computer, where the whole house and every control fit on one screen.
5:00 PM
Solar
Home
Battery
Grid
What it produces
8.20 kWDC
11,890kWh a year
$1,785a year
5kWh battery
How to use it
- Pick the modules and how many. The array fills the roof and starts to glitter as it produces.
- Choose microinverters or a string inverter, then the model. The equipment appears on the wall where it would really be mounted.
- Add a battery, a backup panel or an AC disconnect if the job has one.
- Set the main panel — busbar and main breaker ratings — or tap the panel on the house.
- Move the clock, or press play, to watch a full day: solar in the daytime, the battery after sunset, the grid when the battery runs low.
When something doesn’t fit, the power stops at that component, the part turns red, and you get the ways to fix it. Switch to Plan view to see the same system as a line diagram with the wire table.
What the colors mean
| Color | What it shows |
|---|---|
| Gold | Solar power, from the roof to the main panel and out to the grid |
| Blue | The battery supplying the house |
| Lavender | Power bought from the grid |
| Red | Where the power stops, and why |
What it checks
- The 120% rule. The main breaker plus the backfeed breaker against 120% of the busbar, per NEC 705.12, with the backfeed breaker at the opposite end from the main.
- Backfeed breaker size. 125% of the combined inverter and battery output, rounded up to a standard breaker.
- Module and microinverter match. Whether the module is within the microinverter’s rated range, and how many branch circuits the array needs.
- Inverter size. The array’s DC power against the inverter’s AC rating.
- Battery coupling. Whether the battery is AC-coupled (it adds backfeed) or DC-coupled (it needs a matching inverter).
The wire table follows the format on our plan sets: wire ampacity, temperature derate and conduit fill, the 75 °C terminal rating, and the current at 125%. For runs that need a closer look at distance, use the voltage drop calculator; for the busbar alone, the busbar 120% calculator.
Common questions
What does the line diagram builder check?
The 120% busbar rule from NEC 705.12, the backfeed breaker at 125% of the inverter and battery output, whether the module suits the microinverter, how many branch circuits the array needs, the inverter’s DC-to-AC ratio, and whether the battery is AC- or DC-coupled. The plan view adds a wire table in the same format as our plan sets.
Can I submit this diagram for a permit?
No. It is a preliminary design that shows how the system fits together. The permit set is drawn for your jurisdiction and PE-stamped by Solar Designs USA: $250 flat for systems under 20 kW, delivered in 24 hours.
What if the main panel can’t take the backfeed?
The builder shows every way to connect it: derate the main breaker, limit the backfeed with a power control system (PCS), upgrade to a 225 A busbar, or connect on the supply side. You can switch between them, or go back to the standard breaker, at any time.
How is the production estimate worked out?
It uses about 1,450 kWh per kW of modules per year, typical for a south-facing roof in Tampa, and $0.15 per kWh. Real production depends on the roof’s direction and pitch, shading and location; the clock’s day uses a simple sun and household-use model to show how solar, battery and grid share the load.