Bonding metal roof under PV

Kerry50

Member
Location
Finger Lakes, NY
Occupation
Electrician, PV installer
Last year I added 11 modules to an existing grid tied system. NYSERDA is now requiring me to go back and bond the ribbed metal under the array to the whole system. They are citing articles 690.43(b) and 250.110. This seems like an exaggerated interpretation to me and also to my local inspector (as well as a double standard) but I am preparing to go do it anyway. Does anyone here have a recommendation as to best practices for doing this? My intention is to lift the ridge cap, grind off the paint in spots with a dremel, and bond to the racking as one would with a pool using solid copper and lugs. Then cover the spots with a high temp corrosion protectant.
Thanks in advance for any advice/thoughts on this.
 

don_resqcapt19

Moderator
Staff member
Location
Illinois
Occupation
retired electrician
Unfortunately NYSERDA does require it. I think it is absurd. I have Always been unclear on if NYSERDA can require such things. They will fully admit that they are not the AHJ so it would be an interesting legal challenge.
They can require anything they want to, if they have the legal authority to do spo, but no matter what authority they may have, the cited sections do not require the roof to be bonded.
 

Carultch

Senior Member
Location
Massachusetts
Unfortunately NYSERDA does require it. I think it is absurd. I have Always been unclear on if NYSERDA can require such things. They will fully admit that they are not the AHJ so it would be an interesting legal challenge.
How exactly are you supposed to bond metal roofing, when S-5 clamps and similar products are specifically designed with round point setscrews to avoid damaging the roof panel coating? Unless that coating is conductive (like galvalume or zinc coated), or the metal doesn't have a coating (like mill-finish copper roofing), you are trapped between two mutually exclusive requirements: A) to not damage the coating, and B) to bond the metal roofing.
 
How exactly are you supposed to bond metal roofing, when S-5 clamps and similar products are specifically designed with round point setscrews to avoid damaging the roof panel coating? Unless that coating is conductive (like galvalume or zinc coated), or the metal doesn't have a coating (like mill-finish copper roofing), you are trapped between two mutually exclusive requirements: A) to not damage the coating, and B) to bond the metal roofing.
Typically by using lugs and toothed washers underneath the ridge cap, pretty much as the OP said.
 

Kerry50

Member
Location
Finger Lakes, NY
Occupation
Electrician, PV installer
It is one thing for NYSERDA to say they require it, they have that authority as the AHJ. However it is another thing for them to cite articles which don't require it. It is confusing and unprofessional.
I reached out to Sean White of Whitehouse solar who provided this helpful link:
https://www.nyserda.ny.gov/-/media/NYSun/files/Understanding-Solar-PV-Permitting-Inspecting.pdf
on page 21 it states:
"The equipment grounding conductor (EGC) does not carry current under normal conditions. It provides a path back to the grounded conductor (neutral) when a fault occurs. The EGC may include all bonded metal components, such as the racking, boxes, enclosures, building steel, and metal roofing materials. (Bonding is the physical connecting of metal components so that they are at equal potential. They may or may not be grounded. Bonding jumpers may be extensions of the GEC, EGC, or grounded conductor.) Table 250.122 in the NEC governs EGC sizing. The EGC is required on both grounded and ungrounded (transformer-less) systems. The EGC must be a minimum of #6 AWG when exposed and must be bare or insulated green. When exposed and insulated, the wire must be UV-protected."
So to remain in good standing with NYSERDA I will return to the job and bond all metal roofing underneath the array to the racking.
Thanks to everyone for the feedback.
 

jaggedben

Senior Member
Location
Northern California
Occupation
Solar and Energy Storage Installer
NYSERDA is NOT the AHJ. Even they will admit they are not. I have not looked, but I suspect they have some general statement that to get the funding the system must be approved by NYSERDA, allowing them to require whatever they want.
It's still a question what's the basis to appeal their requests, right? I mean, what if they demanded you paint all the conduit chartreuse? :D
 
It's still a question what's the basis to appeal their requests, right? I mean, what if they demanded you paint all the conduit chartreuse? :D
Yeah I dont know if there is an appeal process. There is one guy there that seems to be the technical/code guy, and he seems to have the last word. I only do a few resi systems a year so for me its probably not worth a fight- I mean chartreuse is quite pretty IMO...
 
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