enphase IQ8D-72-E-US Design Manual page 80

L1-L2 : 35 Microinverters, L2-L3: 34 Microinverters and L3-L1: 34 Microinverters.
The calculation for main breaker size is as follows:
Current (A per branch) = [633 Watts/Microinverter × 35 Microinverters × √3 ]÷ 208 volts = 184 A
The ampacity result is 184 A
OCPD sizing = 184 Amps × 1.25 = 230 A
A PV system with 103 IQ8D Microinverters requires a 250A (minimum) circuit breaker or OCPD.
NOTE: The above methodology is used only for ease of calculations for an unbalanced system. The real current calculations shall
involve vector mathematics for current addition as each Microinverter is connected across each phase shall contribute current to all 3
lines – L1, L2 and L3 cables.
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