solarken
NABCEP PVIP
- Location
- Hudson, OH, USA
- Occupation
- Solar Design and Installation Professional
On a small commercial PV install, on an EPDM membrane roof with ballasted racking, I originally was going to use rigid metal conduit for wiring leaving the array, but as I have been building the array I am thinking it will not be feasible, and am considering PVC. The roof structure has sloped framing for drainage but the last time it was reroofed, the roofer built up the foam underneath the EPDM to create these weird peaks and swales (photo attached) in an effort to direct water to the drains. The array is divided into two subarrays, as I had to find the flattest contiguous surfaces to avoid issues with the ballasted racking spanning the peaks and swales. So I need to bring conductors from two strings, and an EGC from the smaller array about 13 ft to the larger array, over an undulating path across the roof, and then in another spot I need to bring conduit from a jbox under a module about 4 feet to two EPDM pipe flashing boots near a parapet wall and through two LB's down into the building.
I don't see how I can easily use RMC, because I am going to have to come out from array at about 3 inches above roof, bend up to the 6 inch height of roof supports, probably dura-blok, come across a peak and a valley of foam (near a drain), and bend back down to 3 inches to get under the other array. At the jbox the roof height is relatively flat and less of an issue, but I may need to make a bend horizontally.
I am thinking PVC will be easier to deal with the bends. Any thoughts on this? Should I use schedule 80? Should I prime and paint the PVC? I would rather not use EMT as I think PVC will last longer and I can bend it with a heat gun rather than making exotic bends on a roof with the EMT hand bender.
Thanks, Ken
I don't see how I can easily use RMC, because I am going to have to come out from array at about 3 inches above roof, bend up to the 6 inch height of roof supports, probably dura-blok, come across a peak and a valley of foam (near a drain), and bend back down to 3 inches to get under the other array. At the jbox the roof height is relatively flat and less of an issue, but I may need to make a bend horizontally.
I am thinking PVC will be easier to deal with the bends. Any thoughts on this? Should I use schedule 80? Should I prime and paint the PVC? I would rather not use EMT as I think PVC will last longer and I can bend it with a heat gun rather than making exotic bends on a roof with the EMT hand bender.
Thanks, Ken