Size surge protective devices (SPDs) for PV systems on both DC and AC sides per NEC 690.35.
Input Parameters
Results
--
DC SPD Voltage Rating
V
--
AC SPD Voltage Rating
V
--
Min Surge Rating
kA
--
Lightning Risk
Note: NEC 690.35 requires SPDs for PV systems >1kW. Type 1 SPDs for service entrance, Type 2 at inverter. Replace SPDs after major surge events.
Reference
DC SPD Rating = ceil(Voc_max × 1.2) rounded to 100V
AC SPD Rating = ceil(V_ac × 1.5) rounded to 100V
Surge kA = Base × Exposure × Lightning_factor
Exposure: Rooftop=1.0, Ground=1.5, Carport=1.2
Lightning Factor = 1 + density/10