Solar planning for new construction

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Don't do it. It is an idea that has failed multiple times. The fundamental problem is that if it needs service either for solar production or leaks, you need someone familiar with the exact product to service it. So if the manufacturer or installer goes out of business you're SOL.
 
Zee said:
You may be right.
It is a Code violation in these parts though to put PV over a plumbing vent.
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Can you provide a code citation for that? I've only been able to cite CPC 310.5, but I feel like that's a stretch. Manufactures installation instructions sometimes specifically prohibit this.
 
Joe.B said:
Can you provide a code citation for that? I've only been able to cite CPC 310.5, but I feel like that's a stretch. Manufactures installation instructions sometimes specifically prohibit this.
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310.5 would plausibly apply if the panel is so close to the top of the plumbing vent that the net free area between them is smaller than the interior area of the vent pipe.

If you do the math, when the end of the plumbing vent is cut square, the vent is plumb, and the panel is parallel to the roof plane, even when the panel is touching the vent at the downslope point, that can't happen if the roof slope is 6:12 or greater. And that answer is for an arbitrary pipe diameter and pipe wall thickness; for real world pipe sizes, the maximum slope at which you could obstruct the vent is even lower than 6:12.

And even for a flat roof, you'd just need to raise the pipe 1/4 its diameter above the end of the vent to get sufficient free area. Although in that case you may well not be installing the panels parallel to the roof plane.

Given that, CPC 310.5 is almost never an issue. The only issue I could see is CPC 906.1, which says the vent needs to terminate at least 6" vertically above the roof. If your racking method raises the panels high enough to allow the vent to still comply with that, I see no general prohibition on running panels over a roof plumbing vent.

Cheers, Wayne
 
wwhitney said:
Given that, CPC 310.5 is almost never an issue. The only issue I could see is CPC 906.1, which says the vent needs to terminate at least 6" vertically above the roof. If your racking method raises the panels high enough to allow the vent to still comply with that, I see no general prohibition on running panels over a roof plumbing vent.

Cheers, Wayne
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That's all I've been able to come up with in code, and some products prohibit it in their installation instructions. It's generally accepted as a bad idea and most people think it's a code violation, as @Zee just mentioned. Any time anybody says something is a violation I want to see it in code.
 
Joe.B said:
Can you provide a code citation for that? I've only been able to cite CPC 310.5, but I feel like that's a stretch. Manufactures installation instructions sometimes specifically prohibit this.
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No, I cannot provide a code citation, sorry. I meant to say the local AHJ's do not allow it. I do not know how it relates to Code.
 
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