earshavewalls
Senior Member
We have a local installer who wishes to install a PV system (DC string-type) on a residential roof that has painted steel shingles. We are concerned about how to bond these shingles. Unlike a standing seam or corrugated roof, the shingles are not electrically connected to each other, but are installed the same as a clay or concrete tile shingle. Has anyone out there come across this type of installation? We are considering three options for the installer:
1) Provide bonding jumpers to electrically connect all metal shingles
2) Re-roof under the array with asphalt shingles (flash three sides), leave a minimum 4" air gap between metal portions of the array and the roof.
3) Re-roof the entire house with non-metallic shingles
Are we on point on this issue or am I missing something that would exempt the issue of bonding the metal roofing materials?
We are basing this decision on the following code articles: 250.4(A)(4) and (5) (non-current-carrying electrically conductive materials); 250.8(A) & (B) (Methods); 250.12; 690.43(A) & (C) (PV system equipment grounding).
Any input would be appreciated. We want to make the right call here, which we believe we are doing, but we also would like to hear some consensus on the matter.
Thanks,
Wayne
1) Provide bonding jumpers to electrically connect all metal shingles
2) Re-roof under the array with asphalt shingles (flash three sides), leave a minimum 4" air gap between metal portions of the array and the roof.
3) Re-roof the entire house with non-metallic shingles
Are we on point on this issue or am I missing something that would exempt the issue of bonding the metal roofing materials?
We are basing this decision on the following code articles: 250.4(A)(4) and (5) (non-current-carrying electrically conductive materials); 250.8(A) & (B) (Methods); 250.12; 690.43(A) & (C) (PV system equipment grounding).
Any input would be appreciated. We want to make the right call here, which we believe we are doing, but we also would like to hear some consensus on the matter.
Thanks,
Wayne