safety with high voltages in ground-mount "string" systems

[peakbagger]

If I was going to try, I would brush blast the outer edges of the frames (voiding any warrantee) and then install backer rod between the panels and a good thick seam of Sikaflex. I have tried other sealants and it hard to beat Sikaflex. The key is to get some backer rod in the mix to absorb the expansion and contraction while the skikaflex handles the waterproofing.

[J.P.M.]

Well, I'll probably tilt at my latitude, 36 degrees, so not that horizontal.

sin 36 = 0.588 of it is. Still, everything under the array will probably be more horizontal than the array and that projected (more/mostly)horizontal area will get just as wet unless the gaps are sealed in a fashion as Peakbagger suggests, but as he also advises, that'll probably void any warranty.

My other point was that sealing a surface that is not protected from water flowing from a higher elevation by layered surfaces that keep flowing water from the joint/seam will be less reliable than one that is protected in such a way. That is, it's better to keep water away from a seam in the first place and then seal it as well as possible as backup/insurance.

Bottom line: As a practical matter, PV arrays make lousy water barriers with respect to leak tightness and the spaces between panels will always leak, but suit yourself. As for a water barrier under the panels, that'll have a better chance of not leaking but will cost more, get dirty, collect junk, be hard to access/clean and in general be a PITA besides probably impairing panel efficiency a bit.

[RShackleford]

Bottom line: As a practical matter, PV arrays make lousy water barriers with respect to leak tightness and the spaces between panels will always leak, but suit yourself. As for a water barrier under the panels, that'll have a better chance of not leaking but will cost more, get dirty, collect junk, be hard to access/clean and in general be a PITA besides probably impairing panel efficiency a bit.

So basically you're saying (actualy you did say) don't plan on storing anything under there that can't get wet. Oh well, "the wife" will appreciate hiding the trash cans, at least.

[J.P.M.]

So basically you're saying (actualy you did say) don't plan on storing anything under there that can't get wet. Oh well, "the wife" will appreciate hiding the trash cans, at least.

Among other factors including system maint. and perhaps some safety issues, yes.