String Sizer

South Sound Solar · Internal Design Resource

PV String Sizing Check

Screen module and inverter combinations before final engineering—then compare practical string layouts in one clear view.

Planning tool only. Confirm every design against current manufacturer documentation, site conditions, NEC requirements, utility rules, and the authority having jurisdiction before proposal, permit, procurement, or installation.

1 Define the array

Cold design input14°F ambient
Hot design input149°F cell

Preset screening temperatures for Thurston County. Use project-specific temperatures when finalizing the design.

2 · Recommended starting point

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Choose an array to begin.

Planning check
—Cold Voc, longest string
—Hot Vmp, shortest string
—Module Isc per MPPT
—DC-to-AC ratio
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3 · Compare

Valid string layouts

Balanced layouts are shown longest-string first. Select one to review its checks.

4 · Verify

Selected layout checks

Green means the screening value is inside the stored limit—not that the design is approved.

Data, assumptions, and limitations

Internal use only · Values are screening estimates and may change as products, labels, firmware, codes, and local requirements change. One series string per MPPT is assumed; parallel-input and jumper configurations are outside this tool.