NEC 705 Question

[Xamacho]

Referring to 2014 edition here.

705.12(C) Greater than 100 kW VS 705.12(D)(1) Dedicated Overcurrent and Disconnect

I am designing a 144 kW system with five 30 kW utility interactive inverters, batteries, transfer switches, micro-grid controllers, etc. It is a complex system and without getting into nitty gritty details, and there are lot of them, I was wondering if I could propose this question: Is it possible to have one inverter make a Load Side connection into a panelboard, say on the third floor, and to have the other four inverters make a load side connection into a panelboard, say on the first floor? The first floor inverters tie into four OCPDs at a "MLO PV Load Center" which then goes to a single PV breaker at the Main Panel.

What is the forums experience on this subject?

Thanks,
Michael


Side Question: If an inverter is rated 44 amps maximum AC current, and but the inverter company specifies a 50 Amp continuous operation rated breaker, am I allowed to design for this current or do I design OCPD and conductors for 125 percent of max current (55 Amps, next size up being 60 Amp breaker)?

 

[ggunn]

Referring to 2014 edition here.

705.12(C) Greater than 100 kW VS 705.12(D)(1) Dedicated Overcurrent and Disconnect

I am designing a 144 kW system with five 30 kW utility interactive inverters, batteries, transfer switches, micro-grid controllers, etc. It is a complex system and without getting into nitty gritty details, and there are lot of them, I was wondering if I could propose this question: Is it possible to have one inverter make a Load Side connection into a panelboard, say on the third floor, and to have the other four inverters make a load side connection into a panelboard, say on the first floor? The first floor inverters tie into four OCPDs at a "MLO PV Load Center" which then goes to a single PV breaker at the Main Panel.

I won't comment on batteries and transfer switches, but with straight grid tied inverters there is no code reason why you cannot connect load side at more than one point. However, some AHJ's will allow more than one point of interconnection, some will not, and with some "it depends".

 

[jaggedben]

Your question is really the same as this concurrent thread, (which I wish was more off topic, but whatever).

To summarize, what's more likely to trip you up is utility disconnect requirements, rather than the NEC. Especially at that power level.