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If I bond the negative PV outputs of my planned ground-mounted array to ground (a solidly grounded system), 2017 NEC 690.41(B) allows ground-fault protection to be optional. The charge controllers will be in a small dedicated equipment cabinet/shed detached from the house, and the connection between them run underground through IMC conduit.
Morningstar's GFPD-600V ground-fault disconnect isn't exactly free at around $400, but I'd be willing to include it if there were a significant safety benefit, or if it simplified code compliance in some other way. Other than the cost and the need for a bit more space next to the CCs, I don't see a downside to having the array "functionally grounded" through the GFPD. Having to switch both positive and negative with the PV disconnect (per NEC 690.15) isn't an issue because I'm planning to do that anyhow.
This system won't include arc-fault detection, as that is thankfully exempted by 2017 NEC 690.11, one of the reasons I'm using this detached solar shed along with avoiding any rapid shutdown hassles. So, does that make sensitive ground-fault detection (Morningstar claims 300 mA of fault current will trip the thing) more important?
Thoughts?
Morningstar's GFPD-600V ground-fault disconnect isn't exactly free at around $400, but I'd be willing to include it if there were a significant safety benefit, or if it simplified code compliance in some other way. Other than the cost and the need for a bit more space next to the CCs, I don't see a downside to having the array "functionally grounded" through the GFPD. Having to switch both positive and negative with the PV disconnect (per NEC 690.15) isn't an issue because I'm planning to do that anyhow.
This system won't include arc-fault detection, as that is thankfully exempted by 2017 NEC 690.11, one of the reasons I'm using this detached solar shed along with avoiding any rapid shutdown hassles. So, does that make sensitive ground-fault detection (Morningstar claims 300 mA of fault current will trip the thing) more important?
Thoughts?