OzSolar
Whatever you did, that's what you planned.
TAPTITE, also called Tri-lobular screws very handy for grounding the metal framework. That combined with star washers is all we used to have the integral grounding ground mounting hardware arrived.
Ground mount ground question
- Thread starter Subdood
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peakbagger
Solar Enthusiast
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BTW, bolting anodized aluminum frames to galvanized Unistrut directly is considered bad practice as depending on the level of salt and other corrosives in the area, galvanic action will eventually deteriorate the Unistrut. In coastal areas this will show up quickly like in couple of years, less quickly like in the mountains where I live but I see it on my original 20 plus year old system. The superstrut (gold color) has given up a lot of its zinc and is rusting in spots where the frames are in direct contact with the strut. The method I used on subsequent installations is to make washers out of 1/16" thick UNHMW sheet stock with a slot in them. When I put the panels in place but before snugging the bolts, I slipped the washers in between the frame and the strut to isolate two metals. Its been 15 years and no signs of rust or pitting.
Subdood
Photon Wrangler
We're in NE Kentucky, so there's no issue with salt in the air, but it is a humid environment. From what I've read, unless there is a catalyst like salt, then anodized aluminum and galvanized steel shouldn't corrode. But, that's in theory, as you mentioned it does happen in a salt air- free environment.
This plastic sheeting you put between the frames and rails, wouldn't it crack or split when you tighten up the frame bolts?
Has anyone on here had corrosion issues with the anodized AL panel frames and galvanized steel rails? I'm asking those who are not in coastal areas.
peakbagger
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UHMW is designed for that type of service. Yes it will extrude eventually under enough pressure but I just snugged my fasteners (all stainless)and use nylock nuts to keep them from moving. I am about 100 miles from the coast with the White mountains between me and the coast so salt air is not an issue.
My guess is the corrosion comes from atmospheric deposition on the panels. Acid rain is far less of an issue these days but rainwater is still somewhat acidic and its slowly will collect and concentrate in areas that stay wet. As I said not a short term issue. Not a lot of folks with 20 plus year old array out there so maybe I am just ahead of the curve.
My guess is the corrosion comes from atmospheric deposition on the panels. Acid rain is far less of an issue these days but rainwater is still somewhat acidic and its slowly will collect and concentrate in areas that stay wet. As I said not a short term issue. Not a lot of folks with 20 plus year old array out there so maybe I am just ahead of the curve.
Subdood
Photon Wrangler
Well, the attached frames are on the bottom and at an angle, so water shouldn't collect. But, there's condensation/fog/humidity to deal with.
Where are the White Mountains, in New England?
Do you happen to have a pic of these nuts you used? Are they just cone nuts that can be used in unistruts? What kind of metal are these nuts?
MarkSolar
Solar Enthusiast
My ground mount came with galvanic insulators to be installed between the aluminum rails and steel mounting tubes. Here's the page out of the instructions that shows it:
peakbagger
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No pictures that are easy to get to. The panels are hung off horizontal half height superstrut that are aligned with the solar panel mounting holes drilled in the back of the frame. I think the holes were sized for 1/4" bolts with some clearance. I took standard spring back strut nuts drilled for 1/4" bolts and then screwed a standard SS bolt up through the back of the strut nut and snugged it up tight. When I slide the strut nut in the rail I end up with short threaded studs sticking up from the face of the strut. The panel then drops down over the studs. The panel is now supported. I have big fingers, but I could reach in between the panel and the frame and slide a washer over the stub and then a nylock nut. Once I have it started. I would lift up the panel and slide the home made square UHMW washer with slot down over the stud between the PV frame and the strut. I then tightened the nut with an open end wrench and some patience. Its a tight fit so the wrench can only turn about 30 degrees at most so its lots of partial turns. Buy spare hardware its easy to drop the washers and nuts.
I installed my pole mount completely solo including the 50 bags of Sakrete for the pole. I could have just used a SS bolt from the inside of the PV frame down to a threaded strut nut and loose the nylock capability but that meant using two hands to try to stabilize way too many components while trying to get the bolt in. Making my strut nuts into studs makes it a lot easier to get things lined up. I eventually figured out I could install the strut nuts and SS bolts with the panel on a sawhorse and leaving things loose, then lifting it up and sliding the panel onto the superstrut from the edge of the array and slide the panel to its intended location, then repeating the snug up and washer phase.
Obviously, this only works if you have access to the back of the array. BTW I use all stainless nuts and bolts, everyone gets a dab of never seize. SS threads can gall in a heartbeat right out of the box and the time taken to remove a galled thread is lot longer than dabbing a bit of never seize. I buy the SS in boxes of 100 from Hamilton Marine in Maine when they have a 20% off sale in the spring and fall.
I installed my pole mount completely solo including the 50 bags of Sakrete for the pole. I could have just used a SS bolt from the inside of the PV frame down to a threaded strut nut and loose the nylock capability but that meant using two hands to try to stabilize way too many components while trying to get the bolt in. Making my strut nuts into studs makes it a lot easier to get things lined up. I eventually figured out I could install the strut nuts and SS bolts with the panel on a sawhorse and leaving things loose, then lifting it up and sliding the panel onto the superstrut from the edge of the array and slide the panel to its intended location, then repeating the snug up and washer phase.
Obviously, this only works if you have access to the back of the array. BTW I use all stainless nuts and bolts, everyone gets a dab of never seize. SS threads can gall in a heartbeat right out of the box and the time taken to remove a galled thread is lot longer than dabbing a bit of never seize. I buy the SS in boxes of 100 from Hamilton Marine in Maine when they have a 20% off sale in the spring and fall.
Very nice, you’ll love bi-facials… you’ve done a great job keeping the back side clear of mounting related shadowing. That’s gorgeous, you don’t often see such long/large home built ground mounts, you can be proud of that one, well done!!!
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Subdood
Photon Wrangler
Thank you, I'm very happy the way it came out. I've had the panels since August but didn't get my inverter until late October, so I started on the ground mount in early November. Between me getting sick twice and very cold and wet weather in between, it took me over 3 months to get it done. We have a high water table so I had to wait until holes would drain before I felt comfortable about pouring the concrete for the front posts.
I got the panels from Santan Solar, they were bought by an installer, but never put in service so they are practically new other than a few scratches on the frames. They are Canadian Solar 445W bifacials. They are beasts, about 7x3.5 feet and 63lb each. I built the array myself, but had to have my wife help me put them on.
Yeah, the mount seems high off the ground, but I had to do it this way because of the slope of the hill to keep it leveled. So, an added benefit is that the back side cells get more incidental exposure. The highest point the east panel is at about 6.5ft. I have considered putting down white gravel under the mount when I'm done running wires to help with reflecting more light onto the backside.
I should post my pics from beginning to now on the Show and Tell thread. Do you have bifacials? Do they work as advertised?
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timselectric
If I can do it, you can do it.
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Howdy, up river neighbor.
It takes longer around here, but still happens.
Nothing conductive should touch the panel frames except for aluminum, or stainless steel.
And definitely not treated wood, it's very corrosive.
Subdood
Photon Wrangler
Hey there western neighbor.
So you think I should remove the panels and put something in between the frames and struts then? Any suggestions to any certain material, such as the plastic sheeting Peakbagger used or something different?
The frames aren't touching the treated wood anywhere.
BTW, how did you get 24kW of panels on a roof?? Do you have them on a barn or multiple structures? Just curious.
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timselectric
If I can do it, you can do it.
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A large stainless steel washer would do. Or some type of plastic.
100 panels carried up a ladder, to the roof of my house. My wallet overruled my back. lol
Subdood
Photon Wrangler
You must have a big house, and or covered every square foot with a panel. Plus, you carried them up by yourself??
OffGridForGood
Catch, make or grow everything you can.
I used the stainless washers (with the little teeth) since both the PV frames and the unistrut will both need to be grounded, and where I am they don't count the bolt as electrial connection between the frame and unitstrut, even if a meter showns the two at the same potential.
timselectric
If I can do it, you can do it.
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All by myself. My back is still upset with me. lol
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Subdood
Photon Wrangler
A large stainless steel washer would do. Or some type of plastic.
I used the stainless washers (with the little teeth)
Those washers would have to be pretty large to separate the frame and the struts. What size washer are we talking about?
I used the stainless washers (with the little teeth)
Those washers would have to be pretty large to separate the frame and the struts. What size washer are we talking about?
timselectric
If I can do it, you can do it.
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They're called weebs.
They come in many types and sizes.
FilterGuy
Solar Engineering Consultant - EG4 and Consumers
I had always thought that the Weebs and racking system have to be certified as a set. However, I just looked at the 2023 code and I am no longer so sure:
Can you have a 'generic' WEEB that is listed or does the whole racking system have to be listed?
timselectric
If I can do it, you can do it.
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Weebs are listed on their own.
As far as I know, they are universally acceptable now.
Subdood
Photon Wrangler
I thought Weebs were used to connect the panel frames to the grounding wire? I'm talking about washers between the struts and frames. Sorry if I'm not getting it. Maybe I'm a Dweeb. Sorry, couldn't resist..
BTW, which one of you is the UK fan??
Kudos on your solar roof, that's impressive, especially doing it yourself.
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