Solar Wire Sizer

About this app

Solar Wire Sizer helps solar energy professionals select the correct wire size for PV systems based on NEC standards. FEATURES: - Wire sizing per NEC Table 310.16 ampacity ratings - Max circuit current per NEC 690.8(A)(1): Isc x 1.25, then both printed 690.8(B) checks: base ampacity vs 156%, corrected ampacity vs 125% - Voltage drop calculation with configurable thresholds (2-3%) - Temperature derating per NEC Table 310.15(B)(1) - Copper and aluminum conductor support - DC, AC single-phase, and AC three-phase circuits - 60C, 75C, and 90C insulation temperature ratings - Wire sizes from 14 AWG to 500 kcmil NEC COMPLIANCE: - NEC 690.8(A),(B)(1),(B)(2) - PV circuit current and two-step conductor ampacity - NEC 690.31 - Methods permitted for PV wiring - NEC Table 310.16 - Allowable ampacities of insulated conductors - NEC Table 310.15(B)(1) - Ambient temperature correction factors - NEC Chapter 9 Table 8 - DC resistance values OPTIONAL PRO UPGRADE - $2.99 ONE-TIME IN-APP PURCHASE The following features require a separate one-time in-app purchase. They are not required to use the calculator: - Unlimited saved calculation history - PDF export of results - Dark theme - Ad-free experience UPGRADE TO PRO: - Remove banner ads - Unlimited calculations - Dark theme support Designed for solar installers, electricians, and PV system designers working in the United States.

Conductor sizing now follows the printed two-step NEC 690.8(B) check: - (B)(1) base ampacity vs 156% of Isc, (B)(2) corrected ampacity vs 125% - no more over-derating on hot or bundled runs - Voltage drop now computed at 125% max circuit current (was 156%) - Aluminum 300 kcmil corrected to printed 310.16 values (195/260 A)

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1. First observed Oct 16, 2026 · 4:59 PM $0.99