Guys(Gals),

I'm having "engineer's block" so to speak. We have (3) line commutated solar inverters that kick out 12kW AC each. Each inverter is rated single phase 240V, so there's one phase and a neutral (and EGC, not shown on image). Inverter A lands on phase A, B on B, and C on C inside a panelboard, so as to create a three phase system.

My struggle is sizing the inverter OCPD in the panelboard. Logic tells me I have true 12kW per phase, so 12,000/240=50A*1.25=62.5A=70A 3-pole breaker. My mind is drifting towards a calculation that involves 416V (240*sqrt(3)=416), but it doesn't feel right.

I've attached a little sketch detailing. Thanks ahead of time.

I'm having "engineer's block" so to speak. We have (3) line commutated solar inverters that kick out 12kW AC each. Each inverter is rated single phase 240V, so there's one phase and a neutral (and EGC, not shown on image). Inverter A lands on phase A, B on B, and C on C inside a panelboard, so as to create a three phase system.

My struggle is sizing the inverter OCPD in the panelboard. Logic tells me I have true 12kW per phase, so 12,000/240=50A*1.25=62.5A=70A 3-pole breaker. My mind is drifting towards a calculation that involves 416V (240*sqrt(3)=416), but it doesn't feel right.

I've attached a little sketch detailing. Thanks ahead of time.

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