Identify racking system from 2012; worth reusing?

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wwhitney

Senior Member
Location
Berkeley, CA
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Retired
Contemplating a refresh of a small (12 * 250W panels) PV system installed in 2012. A picture of the end of the bottom corner of one of two rows of panels is below. A couple questions:

1) Does anyone recognize the brand/model of the racking system?

2) The existing modules are 65-1/4" in height and sit between the rails. I assume that panels are not currently produced in that particular height, so no drop in replacement would be available. Is it worthwhile to pursue reusing the rails?

E.g. 67-3/4" seems to be a standard height for 108 cell panels, so that could be accommodated by either mounting the panels to the top of the rails and letting them overhang an inch or so top and bottom, or figuring out how to add an offset piece between the rails and the vertical aluminum posts they are mounted on to increase the spacing by 2-1/2".

Thanks,
Wayne


PXL_20241021_205846007.jpg
 
electrofelon said:
Personally, I would have no issue making some modifications to mount new modules on top. Can you just drill and tap (use a forming tap) a hole on top and use top down clamps?
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I could probably make that work. Can you point me towards a good reference on such mounting issues, like whether it's OK to basically clamp the panels at the 4 corners only, and whether the clamps would suffice for interpanel bonding? Or perhaps suggest a manufacturer of such hardware you like, so I can peruse their product offerings and technical info?

Thanks,
Wayne
 
wwhitney said:
I could probably make that work. Can you point me towards a good reference on such mounting issues, like whether it's OK to basically clamp the panels at the 4 corners only, and whether the clamps would suffice for interpanel bonding? Or perhaps suggest a manufacturer of such hardware you like, so I can peruse their product offerings and technical info?

Thanks,
Wayne
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Usually you have to look at the module instructions (its usually not on the spec sheet and can be hard to find) for allowable mounting. Typically you can mount them any way, but the allowable loading will be lower if you mount them the "long" way.

Regarding bonding, maybe others with more experience during that time will comment, but that may have been when WEEBs were common? I have used WEEB's between panels and rails on some homebrew racking. I think technically thats not legit, but whatever. IF you use any sort of modern top down clamp, like an iron ridge UFO, it has the "WEEB" built into it. IF you are going to do a deep dive on this (which I am sure you will ;)) I suspect you will find that you cant "build your own" UL 2703 compliant system with mixed parts.....
 
wwhitney said:
Contemplating a refresh of a small (12 * 250W panels) PV system installed in 2012. A picture of the end of the bottom corner of one of two rows of panels is below. A couple questions:

1) Does anyone recognize the brand/model of the racking system?

2) The existing modules are 65-1/4" in height and sit between the rails. I assume that panels are not currently produced in that particular height, so no drop in replacement would be available. Is it worthwhile to pursue reusing the rails?

E.g. 67-3/4" seems to be a standard height for 108 cell panels, so that could be accommodated by either mounting the panels to the top of the rails and letting them overhang an inch or so top and bottom, or figuring out how to add an offset piece between the rails and the vertical aluminum posts they are mounted on to increase the spacing by 2-1/2".

Thanks,
Wayne


View attachment 2576692
Click to expand...
What are you replacing in the refresh? The modules? The inverter?
I would not recommend modifying that old racking to accept top/midclamp hardware.
 
It might help to know if Wayne just wAnts peace of mind that the new setup will be mechanically and electrically sound, or if he needs it to pass permitting and inspection. You'll probably have a lot more options if it's the former.
 
Racking systems with rails at the top and bottom of each row of modules were rare. I recall something called Sunrail but I barely ever worked with it, and I don't think that's it. So personally I would not try to reuse such racking. Module height has never really been standard.
 
Could be UNIRAC ( solarmount?), or a German brand that made these drop in style rail systems....

It will be laborious to use new clamps with that rail ........which will need to be extensively modified.

So just replace the (E) rails with (N) L-feet on top of (E) posts and add ironridge rails and midclamps (UFOs) (that go between 2 panels).
Place panels on top of both new rails.
Everything will be automatically bonded.
The new 108 cell mods are more like 68" and 69" tall. But still risk being too short for your rail spacing.
Consider standard 66 full cell/132 split cell (AKA half cell) panels, e.g. REC420 or Hanwha Q Cell 400-420. Taller at 74" tall.

Most panels should have no problem supporting that span IMHO.

You can also spin the L feet 180 to get the bottom and top row closer to each other.
 
Zee said:
Could be UNIRAC ( solarmount?), or a German brand that made these drop in style rail systems....

It will be laborious to use new clamps with that rail ........which will need to be extensively modified.

So just replace the (E) rails with (N) L-feet on top of (E) posts and add ironridge rails and midclamps (UFOs) (that go between 2 panels).
Place panels on top of both new rails.
Everything will be automatically bonded.
The new 108 cell mods are more like 68" and 69" tall. But still risk being too short for your rail spacing.
Consider standard 66 full cell/132 split cell (AKA half cell) panels, e.g. REC420 or Hanwha Q Cell 400-420. Taller at 74" tall.

Most panels should have no problem supporting that span IMHO.

You can also spin the L feet 180 to get the bottom and top row closer to each other.
Click to expand...
If there are more than one or two rows of modules, the N-S spatial frequency of the rails may not work with your modules.
 
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Zee said:
Could be UNIRAC ( solarmount?), or a German brand that made these drop in style rail systems....

It will be laborious to use new clamps with that rail ........which will need to be extensively modified.

So just replace the (E) rails with (N) L-feet on top of (E) posts and add ironridge rails and midclamps (UFOs) (that go between 2 panels).
Place panels on top of both new rails.
Everything will be automatically bonded.
The new 108 cell mods are more like 68" and 69" tall. But still risk being too short for your rail spacing.
Consider standard 66 full cell/132 split cell (AKA half cell) panels, e.g. REC420 or Hanwha Q Cell 400-420. Taller at 74" tall.

Most panels should have no problem supporting that span IMHO.

You can also spin the L feet 180 to get the bottom and top row closer to each other.
Click to expand...
If there are two rows of panels and he wants to still have two rows he'll need another row of mounts even if he can make the existing ones partially work.
 
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Assuming I am envisioning the entire array correctly, I would just mount new modules on top of the existing rails. drill and tap holes for your clamps. Use UFOs and just toss the T bolt part and replace with threaded stud. Since the new modules are longer, they will hang over the top and bottom rails. That is no problem. they will share the middle rail, 1 UFO will grab 4 corners.
 
Good points.

3 options if the middle rail is shared by top and bottom row of panels,

1. Bolt on a chunk o' strut (shallow strut!) running up-down.......and 2 L-feet on top of that. One uphill, one downhill rotated 180 for maximum distance from each other.

2. Prosolar made a dual rail mount ......but specific to their bottom-mounted U-rail.

3. Place 2 L-feet on each post in the middle row:
Rotate the L's so the long side lays flat and bolts down to post top. Spin one L uphill for one rail and the other downhill 180 for the other rail. The two form a U. Lay the two on top of each other. Toss the old bolt for the posts and bolt the 2 L's down with a single longer bolt into the post.
 
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Still digesting the recent suggestions. Looking for a mounting design that will comply with all 2020 NEC permitting and inspection requirements. Dug up some old records and have a little more info:

The racking system is called SunEdison/MEMC Alva. Existing panels are MEMC-M240LMA-20 and are 1658 mm tall (not including corner brackets as visible in the photo). If I remove the panels and rails, I will be left with 3 rows of posts that are spaced approximately 1694 mm apart c-t-c "vertically", and 5'-6' apart horizontally within each row. Hip roof; top row of posts does not line up horizontally with the lower two rows.

Ideas so far:

1) If possible, find modern (2020 or later) 1658 mm +/- tall panels with a power density of at least 200W/m^2 STC (vs 146 W/m^2 nominal new STC of existing). Would reusing the existing rails and mounting system in this way be NEC compliant?

2) Mount new panels directly on top of existing rails. Same compliance question. Could add "vertical" rail segments between and flush with existing rails if necessary.

3) Use existing rails as simply a secondary support structure, run new hopefully low profile rails on top of them "vertically". Presumably the support structure for a rail system is not important for the grounding/bounding listing requirements?

4) Remove existing rails and just reuse existing posts. Do modern rail system all require 2 rails per row of panels?

Cheers, Wayne
 
wwhitney said:
...If I remove the panels and rails, I will be left with 3 rows of posts that are spaced approximately 1694 mm apart c-t-c "vertically", and 5'-6' apart horizontally within each row. Hip roof; top row of posts does not line up horizontally with the lower two rows.

...
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You sure that's not (on average) 5'-4" apart horizontally? i.e. two rafters apart at 32" on center?

Assuming that the point loads aren't higher than they should be (big if?), and that the existing mounts are in consistent vertical columns (not staggered), I would place a piece of shallow unistrut running vertically over the top of each column of mounts. Then attach L-feet to the unistrut with strut nuts. Gives you almost total up-down adjustability for four rows of L-feet to attach rails.

If you need to be totally assured of a Class A fire rating that might not be good enough.
 
jaggedben said:
You sure that's not (on average) 5'-4" apart horizontally? i.e. two rafters apart at 32" on center?
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It is every other rafter, but rafter-to-rafter spacing varies from 31-1/2" c-t-c to 37" c-t-c. So the support to support spacing varies from 61" to 71".

jaggedben said:
Assuming that the point loads aren't higher than they should be (big if?), and that the existing mounts are in consistent vertical columns (not staggered),
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As I mentioned, they are not in vertical columns, the top row is one rafter off from the other two. Current array is 5 over 7; the lower two rows of posts extend onto the longest hip jack rafter on each end of the row.

jaggedben said:
I would place a piece of shallow unistrut running vertically over the top of each column of mounts.
Click to expand...
Other than an extra ~2" of height, is there a downside to mounting the shallow vertical strut on top of the existing rails? Looks like as long as the array is within 10" of the roof (or maybe that's 10" to the top of the array), my building department won't require a wind uplift analysis.

jaggedben said:
If you need to be totally assured of a Class A fire rating that might not be good enough.
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Class C suffices, but it does need a rating.

Thanks, Wayne
 
If this was installed in 2012, how old is the roof? And what inverter is installed? You might need to add Rapid shutdown and arc fault protection if replacing the array, so that may trigger replacing the inverter and adding MLPE. At some point you may want to consider just leaving it as is if it's working for a few more years and then replacing everything while replacing the roof. Removing and replacing an array for a reroof is not cheap, especially if you have a McGivered racking system.
If the roof has 15 years left and you want to replace the PV modules, I would probably just remove everything except the mounts, cut any posts down to below the new racking height, and install a modern rail-based racking system like SnapNrack or iron ridge on new butyl mounts like RoofTech mini placed where needed but around the abandoned old mounts. Most butyl mounts can be secured to the decking or to joists, so gives some flexibility.
 
For heaven's sake, ditch that old rail and install your normal gear. We did several jobs with that style of rail back in the day, and each time swore we wouldn't do it again. It took a few times to learn the lesson. Wire management is a major PITA. I wouldn't think twice about it. Go with new rail.
 
yes you need 2 rails per row of panels

rail is cheap

why put strut OVER this unusable/weird rail? how is that better?

I do not understand the complication.

If you are measuring in mm your design requires a degree of precision that does not exist on a rooftop.
 
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