I'm in the middle of getting a 300+kW PV system through permitting. One of the issues with the site is that it's directly adjacent to the 100yr flood plain. We've been approved by there flood plain development department, but during the plan review, the examiner quoted 2011 NEC 682.33. Asking to see our Equipotential plane/ bonding plans.
This is a ground mounted system that is 4' above grade at it's lowest point. And the lowest piece of equipment (solar module, combiner box, Junction box, breaker, inverter, etc) is at least 12" above the electrical datum plane (which is 2' above the 100yr flood level). There is only approximately 20 ft^2 of the array area that would be "overhanging" the water if there were a 100yr flood. At no time would any actual equipment touch the flood waters, only two posts from the ground mounting system would be in the flood water at a whopping 6" depth
My question is, at what point is an equipotential plane needed on a piece of service equipment. The NEC states if the equipment being controlled is "in or on the water" you need an equipotential plane. But can this really apply to a solar array that will only have water underneath a very small fraction of it during a 100yr flood event? 20ft^2 is only 0.13% of the array! And the disconnect for that section is over 100' from that area. I think this is a bit of a streach, that the intent of this part of the NEC was not ment for this type of situation. Or maybe I'm way off base and need to figure out how spec this equipotential plane.
Thanks for any insight on this.
This is a ground mounted system that is 4' above grade at it's lowest point. And the lowest piece of equipment (solar module, combiner box, Junction box, breaker, inverter, etc) is at least 12" above the electrical datum plane (which is 2' above the 100yr flood level). There is only approximately 20 ft^2 of the array area that would be "overhanging" the water if there were a 100yr flood. At no time would any actual equipment touch the flood waters, only two posts from the ground mounting system would be in the flood water at a whopping 6" depth
My question is, at what point is an equipotential plane needed on a piece of service equipment. The NEC states if the equipment being controlled is "in or on the water" you need an equipotential plane. But can this really apply to a solar array that will only have water underneath a very small fraction of it during a 100yr flood event? 20ft^2 is only 0.13% of the array! And the disconnect for that section is over 100' from that area. I think this is a bit of a streach, that the intent of this part of the NEC was not ment for this type of situation. Or maybe I'm way off base and need to figure out how spec this equipotential plane.
Thanks for any insight on this.