User Manual

Planning for a Three-Phase IQ Microinverter System – North America

Ampacity Calculations for Three-Phase Feeders to 240V High-Leg Delta Solar Subpanel

Calculate the ampacity of the 240V high-leg delta three-phase solar subpanel feeders from the continuous

output power rating as follows:

# of Microinverters * Inverter Continuous Output Power Rating = Total Continuous Output Power

Total Continuous Output Power / 240V / 1.732 = Solar Subpanel Continuous Ampacity

IQ 6 (208V)

IQ 6+ (208V)

Continuous Output Power Rating

230VA

280VA

For a solar subpanel with 267 IQ 6+ Microinverters, the continuous output current rating is:

267 ∗ 280𝑉𝐴 = 74,760𝑉𝐴

74760𝑉𝐴 / 240𝑉 / 1.732 = 179.85𝐴

NEC Article 690.9(B) requires a 125% factor be applied to the continuous output current for sizing

overcurrent protection of the branch circuit:

179.85 ∗ 1.25 safety factor = 224.8𝐴

A 225A overcurrent protection device (OCPD) is required for (267) IQ 6+ Microinverters.

240V High-Leg Delta Electrical Schematic