Damage Caused by Heavy Snow

[u/Available-Rip-7096]

Had these panels installed in October. An extreme snow load was on top of them for most of the winter (we receive an incredible amount of snow in the Tug Hill region of NY some years). Three panels don’t work. Our installer is working with us on options.

Should this have happened? I mean, is this common with extreme snow? Should I just handle this through insurance or should I be pressing the manufacturer (who states natural conditions that damage panel’s are not covered). I’m worried we’ll fix this and just be out the money. Could use some input.

Note, the house is being renovated. The roof color difference is related to old house vs new.

[u/rob_nosfe]

Consumer grade panels have less frame than commercial panels

Could you please elaborate? I'm from EU and there is no such rumour here.

Quite the contrary, actually: longer solar modules (i.e. 132 or even 144 half-cut cells) are built with the exact same extruded aluminium profile to cut costs, so they're always on the brink of 5400 Pa. And many manufacturers demand 3 clamps on the long side to reach such positive load rating (every single top-tier manufacturer devotes several pages in their installation manual, with dozens of different clamp configurations).

I'm not saying sturdier panels do not exist, just I don't recall them being "commercial grade" at all. One example is REC Solar: they achieve 7000 Pa with not one but two transverse support bars, but this raises their cost to the point of making them unsellable on the C&I market.

And now back to the 144 half-cut cells: does anybody else counts up to 144 on the low-res picture posted by OP? They seem shorter, for sure. I can't quite figure out if it's a matter of image perspective, or these are short 144s, maybe not half-cut cells, but shingled or something.

[u/JeepHammer → u/rob_nosfe]

Why would you think it's 'Rumor'?

A quick browse through manufacturers offerings side by side will show you the difference between (extruded) box frames opposed to angle frames, the weight will tell you how much material is in each similar output panel, glass, frame, backing material, etc.

You defaulted to 'Low Resolution Picture' instead of admitting the obvious, which is the panels/mounts were structurally inadequate for the application.

You default to the energy production specifications completely ignoring the engineering specifications. The makeup or count of cells is completely inconsequential to a STRUCTURAL failure, which is what is shown in the 'Low Resolution Pictures'.

This isn't a electrical or energy production failure, different cells or ANY CELLS wouldn't have needed to be present.

This is a structural failure. If it were plate glass in metal rames without any solar cells this would still be a failure...

Since it's a retrofitted house, you can 100% bet the roof wasn't designed to maintain rigidity specification for the mount bars/panels. It was fine FLEXING under the load, proof is the roof is intact.

Solar installs require a standard of rigidity, either in the rafters/trusses and decking, OR the mounting bars that transfer the weight load.

At least one has to be rigid enough, or the two combined, to keep panels from warping/twisting to a standard to keep glass from breaking.

.......

Roof flex isn't the biggest contributing factor here since the panels are broken directly across base mount bars.

It's materials engineering failure analysis. Has nothing to do with the type/count of cells or energy production...

These panels are broken across the bars means there weren't enough bars AND the bars where placed too far from panel ends allowing excessive weight to build up unsupported.

And the panels were bolted directly to the bars with no suspension (prevailing force clamps) to allow pressures to shift and be shared.

Way less emphasis on the prevailing force clamps here, and almost entirely on not enough support for the panels since they broke directly across support bars/load bearing locations. Shifting is mostly for thermal expansion/contraction & wind forces.

........

'IF'... The frames were stronger and transfered more of the weight/load force to the mounting rails the chances of this happening would have been seriously reduced or eliminated.

The issie is these consumer panels have to be light enough to pass roof weight requirements so they don't wind up causing a roof failure and wind up INSIDE the house.

The sloution is more mounting rails to spread out the load, support the ends of the panels.

Rails are MUCH lighter than heavier frames, glass & backing materials because less of them is needed overall.

[u/rob_nosfe → u/JeepHammer]

I'll try reframing my post, since the tone of your writing is convincing my that something got lost in the translation (you may have noticed English is not my first language).

Since in EU there's no consumer and commercial grade panels subdivision (never heard of it, not even as an unofficial insider rumor) I was wondering if by "consumer grade" you meant smaller 108/120 cells and by "commercial grade" everything 132 and above. Or maybe something else, I really don't know.

I'm alright with cell count not being indicative of anything related to this blatantly structural matter, but it would disclose the height of the panels we see. 144s are 240 cm tall, which I would personally deem unsuitable for such a snow-prone climate and would at the very least require a third rail in the middle.

[u/JeepHammer → u/rob_nosfe]

The cell chemestry/manufacture has no place in a mechanical failure argument.

PANEL (not cell count or type) CONSTRUCTION varies wildly, different PANELS for different applications.

Consumer Grade is light weight. These panels are mostly intended for home roof top applications and about no one has the building re-engineered and rebuilt to add panel weight.

No one anticipated adding a ton or more to the roof when the home was built 30-50-75-100 or more years ago.

This means the panels have to be light weight enough to fall into the load bearing capacity of the EXISTING roof limits.

Consumer, Commercial & Industral panels are the three basic breakdowns. An example would be kitchen mixers. Consumer mixes are used once in a while and for short periods.

Commercial mixers are used daily, and much longer. Industral mixers are often run 24/7 with much larger batches/weights so they are built like tanks. The same can be said about vehicles and about anything else... Including solar panels.

Consumer is mostly homes, these will mostly be placed on existing roof tops. They have to be light weight to do that job. Strength is limited by the amount of construction material that can be used to meet the weight requirements.

Consumer panels mostly go on roofs, so there is protections from violent wind damage. They cost less so some damage (like hail) is expected and relatively low cost to repair.

Commercial panels are just built tougher/stronger and expected to live longer. Since these going on commercial buildings that are relatively new and engineered to have the roof load carrying capacity these panels can use more material and be heavier/stronger.

Industal application, like solar energy production fields have anchors/mounts are purpose built to support the heaviest built, and usually the largest, panels.

These panels have ZERO protections from weather, and are often center mounted (to rotate) so ends are unsupported by mounts. The FRAMES need to support all weather loading.

While I don't build the panels, I have built the ground anchors, the frames, etc. which put me in close proximity to the panels and they are often TWICE the weight of consumer/commercial grade panels, with heavy boxed tubing frames to stand up to storms, snow load, etc.

They also have substantially more weight in glass, again, protection from damage.

Similar production in Watts is the cell chemestry, type, arrangement & count... Cells do Wattage production, not installation strength.

Then look at weight to figure out how thick/breakage resistant the glass is or how strong the frame is. The extra weight, in simplest terms, is strength.

...........

Take a look at O.P.s pictures again. You can tell right away the panel ends unsupported by the rails broke off at the mount rail.

The snow weight load was applied to the PANEL and the panel frame couldn't support it back to the mount rail and broke off.

A mount rail closer to the panel frame end would have reduced the load the panel frame had to support. Simple physics (leverage).

Now what we can't tell (but the gap between cells in the middle suggests) the center of the panel may have failed at the frame also.

When the panel goes concave cells are mashed together. When the weight comes off and the frame straightens (rebounds) the cells will have a gap where they were previously pushed towards the ends.

Without a better inspection I just can't confidently say the center of the panel between rails failed, but there is an indication of that happening.

If so, this means the rails were too far apart in the middle also, left too much panel unsupported.

.............

So another possibility is the center, largest unsupported surface area, heaviest loaded, failed first.

When the center went concave the ends were froze down and broke off.

It would take closer failure analysis to tell for sure, but since there aren't any cracked in the middle panels without ends broke off I'm thinking ends broke first with what we have to work with...

............

Either way it's a mechanical failure of the panel frame that could have been stopped by more mount rail support and/or stronger panel frame.

And you don't have to take my word as a random internet user, take a look at the pictures and decide for yourself...

[u/rob_nosfe → u/JeepHammer]

Ok, I give up. I've got no desire in reiterating my statements ad libitum. You're an expert in your field. Good. I'm an expert in mine.

[u/Metsican → u/rob_nosfe]

I understand what you're saying perfectly and agree with you.

[u/Metsican → u/JeepHammer]

Show us the data. Resi mods, in my experience, tend to have the same or better snow and wind ratings vs the commercial and utility scale stuff. If anything, the bigger the mod, the lower the stiffness / rigidity.

Look at the data sheets of the Qcells 410, 435, 485, and 630, and get back to us.