Hi Wrenchers, When using a sub-panel for the sole purpose of combining the output of multiple single phase inverters does NEC 690.64 (B) (2) apply? I know that this topic has been discussed but I am still not clear.
The "Can we Land" Article pg 11 Diagram 2b shows that using a Subpanel eliminates the problem of exceeding the 120% rule illustrated in diagram 2a but it does not show the rating of the sub-panel. In the example it shows 3 Fronius 7500W single phase inverters landing in a sub-panel and then the 3-phase sub-panel grid connected to a 80A 3-phase breaker in a 400A main panel. What is the minimum Amp rating required for the 3-phase Sub-panel in diagram 2b? Do we only need to size it for the OCP for the combined outputs of the 3 inverters (80A) or do the three 50A two-pole breakers need to be considered? For easy reference here is a link to the article: http://www.spgsolar.com/wp-content/uploads/2010/05/SPGLeBlancYates.pdf All feedback is appreciated. Al Frishman AeonSolar (917) 699-6641 - cell (888) 460-2867 <http://www.aeonsolar.com/> www.aeonsolar.com
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