sequence of clamping panels to rails

[RShackleford]

I've doing a ground-mount of a 4x4 array of 39x65" panels in landscape orientation. I'll use two pairs of 14ft IronRidge XR1000 rails (supported by wooden girders at each end), at a 26degree angle. The panels will be attached to the rails using IronRidge's little "UFO" clamps; each rail has a clamp at each end, and a clamp between two adjacent panels.

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My question: What is the best sequence for mounting the panels ? I'm worried about even being able to reach the clamps on some of the panels. Looks like maybe professional installers have special ladders that lay across the panels without damaging them; dunno if I can manage without that, or if I can improvise.

If I can mount each row starting at the high (north) side and working downwards, I imagine I can easily lean over the 3ft dimension of the panel to reach the upper UFO. But that means tightening the clamp at the high side all the way (since I won't be able to reach it later); hopefully that is tight enough that the panel doesn't slide downwards, and also requires that tightening the clamps along one edge of the panel, without any clamp at the other edge, does not deform the panel. Alternatively, I could work upwards; that would eliminate the sliding problem; but leaning over that 3ft extent, while the panel is sloping down away from me (about 20", I made the angle be the arc-tangent of 0.5 for simplicity of framing the wood), will be a lot harder, if not impossible, than working downwards.

Anyhow, obviously I have no clue how to do this.

[bob-n]

Each panel is held by four UFOs, two on top and two on the bottom. Where panels meet, they share UFOs. At the very top and very bottom, there are spacers that act like dummy panels. UFOs adapt to different panel thicknesses, but spacers must be the same thickness as your panels.

Start low. The ones near the bottom are easiest, and it gets tougher as you get higher. If you're a perfectionist, you can lay down all four lowest panels with the bottom UFOs loose, align them with a level and laser, and then tighten them at the bottom. We typically spend an hour getting the bottom level and straight, and then the rest just falls into place naturally. Use spare UFOs or spare bolts to temporarily space the panels laterally for a bit of expansion.

Once you have the first row installed and the bottom UFOs tight, place the second row. On this row, you can tighten the in-between UFOs from below over the panels by reaching up or from above reaching down. We find that 39" is roughly the limit of most people to reach across a panel. To tighten them from above, you need a ladder or staging and will be reaching down. That's how you'll have to do the rest. If you think you'll have to lean on the middle of a panel, lay a piece of 3/4" plywood over the whole panel to protect it, but we've found that isn't essential. An electric driver and then the torque wrench gives a moderately tall person enough reach. It is even tougher with the new wide Panasonic panels.

UFOs and all Ironridge bolts must be torqued to spec. "By feel" is most often too tight and runs the risk of damaging the rail. Also, beware of loosening them and then retightening them. It is possible to get them tight but not fully locked into the rails that way. The tee-head must be fully rotated so the tee-ears fully engage the rail shoulder. All Ironridge hardware comes with antiseize pre-applied. If you loosen and retighten a few times, you can wear off the grease coating.

The third and fourth rows will take an even taller ladder or staging to reach safely but again, if you can get up there, you can reach down to torque the in-between UFOs. A piece of plywood may come in handy but we've never needed it.

By tighting the lower row of UFOs in perfect location first, you solve the problem of panels shifting while you get the above panel in place. But it never hurts to inspect the whole array every time you tighten a panel, just to be sure that an accumulation of errors doesn't make things look really awful. Nothing is perfectly straight or perfectly flat, so you will find the gap between panels narrows in one row and widens in another. As long as it doesn't close up, you're OK.

Please don't tell me that you put a ladder on the roof of a pickup truck for extra height. Work safe. Get help.

I hope this helps.

[RShackleford]

Many thanks.

Off the top of your head, do you know the torque-spec for the UFO and for the bolts that hold L-feet to rails ? Perhaps this is my excuse to buy a nicer torque-wrench than the lame Sears beam type that I have !

So starting from the top is a non-starter, because panels will slip downwards ? Obviously rows need to be very tight against each other, as those UFOs are not very big.

This is ground-mount and not a very steep angle, so the top of the array is only about 9ft above grade, and I have an 8ft stepladder. I'm 5'10" with arms an inch too long for my height (so tailors have told me), so I guess the jury is still out on whether I can tighten the UFOs from above; only an issue for the UFOs between rows 2 and 3, and between rows 3 and 4, I guess. What if I cannot reach across that 39" panel that is sloping down away from me ? Hopefully I can, leaning my chest down onto it. But is laying my extension ladder down onto the lower panels, from below, a non-starter ? Obviously would want to cushion it well.

[RShackleford]

As far as alignment, I guess the first step is to get rails right. I'm thinking to temporarily mount the two at the east and west sides of the array. They should be VERY close to parallel, since I'm attaching the L-feet at an easily measured distance apart, and the L-feet can slip slightly on the lag screws holding them to my wooden frame. But that doesn't mean the 4 ends of the two rails form a rectangle (and not a parallelogram), so I measure the diagonals across the corners and slip the rails up or down slightly to get that right. Then add the other 6 rails, easily aligning the ends with the outermost ones. Then get the bottom row of panels straight as you say.

The rails will need about a foot cut off. I have a horror of cutting them too short (8 x $60+), so I'd rather cut 'em after I'm done, if that's reasonable. Leave them long at the bottom end, so easy to access about 3ft above grade. What's best for cutting them ? Hacksaw ? Sawzall ?

[bob-n]

Item	Socket Size	InchLbs	FootLbs
Bonding splice screws	5/16"	20	1.7
Ground lug nuts	7/16"	80	6.7
Grounding lug screws	7/16"	20	1.7
UFO	7/16"	80	6.7
Expansion Joint Nuts	7/16"	80	6.7
Flush Standoffs	1/2"	132	11
Microinverter Nut Kit	7/16"	80	6.7
Frameless module kit nuts	7/16"	80	6.7
3/8" Bonding Hardware Nuts	7/16"	250	20.8
Conduit mount top bolt	7/16"	40	3.3

I keep this info printed in my toolkit for all installations. You can find this and more information on the Ironridge website. They have a brochure for ground mount installation and another for roof mount installation, both with good tips. Ironridge is AMAZING with the level of technical detail they provide. https://base.ironridge.com/ground-ba...ting/resources

Your comment about an 8' stepladder and 9' max panel height sounds marginal but give it a try. You're going to want your chest at the 9' point on the panel so you can get your arm down to the UFO between 3rd and 4th row. You'll definitely be able to do it on all of the rows except perhaps between the 3rd and 4th. Worst case, you'll be holding the torque wrench by your fingers.

I've never laid a ladder on panels. My fear is that an errant toe will dig into the glass.

[bob-n]

Darn, this forum didn't format the table well. Sorry. Let's try the old fashioned way:
torques.jpg

[RShackleford]

Thanks much. Yeah that L-foot torque is surprisingly low; looks like I've got a good excuse to spring for a new tool ("click" type torque wrench)

I don't see anywhere for the square-bolt that connects the L-foot to the XR1000 rail. It's 14mm (or maybe 9/16") so none seem to apply.
Looked at the website, and it looks like it's the thing they call "3/8" bonding hardware", so 250 in-lb; probably not as critical as the UFO anyhow.

[RShackleford]

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I keep this info printed in my toolkit for all installations. You can find this and more information on the Ironridge website. They have a brochure for ground mount installation and another for roof mount installation, both with good tips. Ironridge is AMAZING with the level of technical detail they provide. https://base.ironridge.com/ground-ba...ting/resources

Yeah, that's one way they won me over. And that awesome sample kit they send out for free. They may be more expensive than the competitors, but that XR1000 rail, that can span 8ft, was key fo me, with my wooden sub-structure.

Your comment about an 8' stepladder and 9' max panel height sounds marginal but give it a try. You're going to want your chest at the 9' point on the panel so you can get your arm down to the UFO between 3rd and 4th row. You'll definitely be able to do it on all of the rows except perhaps between the 3rd and 4th.

Standing at 5ft rung of stepladder should put my chest at the 9ft level I'd think. If so, sounds like I'm good to go (I am 5'10" with arms an inch too long for my height, according to a tailor way back when); if not, I'll hire an un-employed hoopster for an hour

[RShackleford]

What's the best way to cut those XR1000 rails, preferably after panels are installed (i.e. not on a miter saw with an abrasive cutting wheel) ?

[peakbagger]

A general observation is a zip wheel on a 4" angle grinder especially on a cordless version is slick way of cleaning up an install. Obviously keep an eye out for the stream of grit and sparks. Obviously cutting it on a miter saw will give a cleaner cut. I usually follow up a zip wheel cut with a hand file to smooth out the rough edges. .

[bob-n]

You mentioned getting a torque wrench. Surprisingly, the Harbor Freight 1/4" click-style torque wrench works well enough for this job. I actually went to the trouble of testing mine by hanging a weight from the handle, and the torque settings were as accurate as I could measure. The "fit and finish" is not as good as the name-brand tools, but functionally, it seems to be just as good.

Purists set their torque wrench to 0 before storing it for the day, thinking it will reduce aging of the spring. Another purist trick is that your hand should be centered on the knurled part of the handle with your middle finger on the unknurled portion in the center, when doing the final click. I can't understand why this matters, but during my testing, this gave the most accurate torque - not enough to matter, but it was most accurate that way.

I found this coupon on the web at www.hfqpdb.com . It expires 5/23/2020. Harbor Freight stores can even scan the image on your cell phone. On rare occasions, people post doctored coupons. There is a 3842_ITEM_PITTSBURGH_CLICK-TYPE_TORQUE_WRENCHES_1584547583.3636.png chance that this one is bogus.

[RShackleford]

Thanks for the coupon, Bob; it does work, however they're talking of long shipping delays, and the store is a trek from here (it IS in stock there though).

This one comes up a lot, get it quick from Amazon, but a minority of bad reviews talk of it not working at all or over-torquing:

https://www.amazon.com/gp/product/B0...KIKX0DER&psc=1

Or Zoro noticed me browsing their site, and sent me a 15% coupon (love it when that happens), which I could use to spring for a $100+ SnapOn wrench

[Ampster]

I did not read the whole thread completely but the advice about getting the first row lined up is good advice. My patio cover was only two rows so it was a lot easer. Also I am sure you have figure this out but access is easier for a patio cover because you can lean across the short width of the panel to do the connectors. As you recall that is why I went with my jury rigged method of washers after my first iteration of mounting panels with the regular clips from the top. Others may not realize that you have access between the rails based on some of the comments I read.
By the way, how is the wood holding up?

[RShackleford]

A general observation is a zip wheel on a 4" angle grinder especially on a cordless version is slick way of cleaning up an install. Obviously keep an eye out for the stream of grit and sparks. Obviously cutting it on a miter saw will give a cleaner cut. I usually follow up a zip wheel cut with a hand file to smooth out the rough edges. .

What's a "zip wheel', some kind of abrasive cutter ? I've found that using abrasives on aluminum leaves a pretty messy flange of melted metal, but maybe I'm using too thick a blade; oh yeah, zip wheel looks like it's less than 1/64" thick, whereas I've used like 1/8" thick on a miter saw. Was wondering about a sawzall, but could be harder to get the cut to be straight.

[peakbagger]

Search for zip wheel on any search engine. I get mine at a welding supply store. Yes its a thin abrasive cutter. I cant justify a plasma cutter but a zip wheel is a big step up from a sawzall. The trade off is a sawzall generates far fewer sparks and grit. An angle grinder is versatile tool, get a few zip wheels, some grinding wheels and some flap wheels and its the perfect tool for small fabrication like Unistrut. I can cut a cleaner straight line with zip wheel than a sawzall.

Just heed my warnings on PPE. Ears, eyes and breathing. A zip wheel or grinder can throw sparks 10 feet. I try to use mine outdoors. I used a N95 mask long before many folks had heard of them.