Newbie here doing a 20.8kW DYI install (80 sunMAX 260W panels with microinverters)

[foo1bar]

That is a 4" schedule 40 pipe in that one picture. It is just a downspout extension. I wasn't aware that would be a concern?

I'd be a little concerned that it'll be cracked/crushed.
You're expecting some parts to settle more than others.
So I'd be concerned that some parts under the pipe won't settle as much as the concrete structure you're making.
And you'll wind up with a lot of pressure on the top of that PVC pipe. Possibly enough to crack it or (more likely I think) crack a nearby fitting

If it's just downspout extension, a little crack won't hurt - you won't have tree roots nearby that'll find the crack and clog up the pipe.
And if it stops functioning in a few years you have equipment to dig in a new one that goes around rather than under the array.

It's probably not a problem - 4" PVC is fairly large - so if you lose some cross section it'll still carry a lot of water. And PVC will flex a fair amount.
And it's not like this is a water supply line where a crack means you suddenly have a mini swamp..

[pclausen]

I'll pull the #4 copper out and tie in a piece of rebar and have it exit the footer by one of the poles.

I used 39 sticks of 1/2 rebar I got for $3.50 a pop. So $135 give or take. That's less than the cost of a single panel, so I figured it would be worth it. Digging the trench didn't cost me anything since I have a backhoe at my disposal. The 11.25 yards of concrete will be pretty expensive on the other hand, but given the very loose fill dirt, I'd rather play it safe. Most of the dirt was only just leveled a few days ago and is very dry and fluffy (have not had any rain for going on 4 weeks now).

That is a 4" schedule 40 pipe in that one picture. It is just a downspout extension. I wasn't aware that would be a concern? I have another 4" schedule 40 downspout extension at the house that is fully encased in concrete. It has not been an issue for the last 15 years.

As for the pic size, I link to images at my own web site. They are reduced from their original size of 1920x1400 to whatever this forum makes them. Looks to be about 1024x768 or something similar to that. If there's a way to have smaller thumbnails and then clicking on them to get the original size, I'd be happy to do so. Not sure if that is supported here?

[foo1bar]

Never seen copper in concrete rot off but then I live in average 20 C all year so no experience with snow . Perhaps its a cold thing?

Bare copper embedded into concrete as a ufer is allowed.
It has to be at least 4AWG and at least 20' long.
I'm not sure that this connection is up to code. Is that connector isn't rated for being embedded in concrete? It probably isn't.
If there's 20' of bare 4AWG copper before the wire comes out of the concrete then it's probably fine.
If you can't do that, then a piece of rebar that sticks out of the concrete is an easy/typical solution. (and probably cheaper than 20' of copper)

Thats a hellova lot of work for 4 support poles .

6 vertical poles.
I think he's gone overboard on the concrete work... I'd think splitting it into two arrays, each with 4 posts would allow you to do just plain holes and have similar risk reduction of modules being damaged.
But it's his money. Hopefully he's got a good deal on all the rebar and the concrete.

One of the pictures shows what looks like could be the top of a white PVC pipe.
Hopefully it's not - it's some rock or something - something that wont' be a problem to put concrete directly on top of.

Never seen copper in concrete rot off but then I live in average 20 C all year so no experience with snow . Perhaps its a cold thing?

Thats a hellova lot of work for 4 support poles . My method would be square Gal tube 3 x 3 with a cross piece of 1/4 reo welded on into holes and concrete in smaller hole 12 inches would be enough. 1/4 rod will lift 2 ton so its enough. When its gone off cut the tops off at your angle and weld on top frame. Done in a tenth of the time . Reo formwork below ground there is just silly in my opinion.Probably some beaurocratic requirement over there but jeesh ! All that concrete and reo and time and MONEY .

I live in a cyclone prone area and have lived through about 5 bad ones and my method is good for satellite mounts , clothes lines, house stumps, shed uprights , you name it. On house stumps we pump it in because its easier to do so in that hectic environment and vibrate it in . No dry mix rubbish which does work but not for this stuff.

When you backfill I would throw some bare copper wire in the trenches . It will add to security if connected to your earth and you may know already connecting it to the earth of your radio TV , HF Transmitter , satellite dish etc increases the ground plane and gives you louder and louder signals the more ground radials you have.

Just as a side note also could the pictures be put in as small ? Would that work. When I want to look I click on them and expand them.
Reason being in other countries we often don't have the download capacity you guys seem to enjoy . It costs me $50 a month for 6 Gigabytes so when you put full size pictures in we have a compulsory expensive download . We don't get a choice.

So smaller would help others. Its a discussion forum Yeh?

[Mike90250]

You need to fish the REBAR up out of the concrete. Copper will rot right off in concrete. Make the connection above the concrete.

[pclausen]

I got the #4 added to the rebar structure.

[pclausen]

I was under the impression that 690.47(D) is going to be removed in the future. Some have nicknamed it 690.47(D)anger as it provides a path for lightning to travel through equipment.



Above illustration is from the following Mike Holt presentation:

https://www.youtube.com/watch?v=YuDqXFvRv94

I don't plan to install circuit breakers at the ground mount system, rather I'll run the string end runs into the same sub-panel the roof mounted strings are. I was planning to run a #6 from the Ironridge grounding lug to the ground rod at the shop building.

That said, I will go ahead and add a #4 to the rebar and run it up one of the mount post to give me the option to tie it into the Ironridge grounding lug if you guys can convince me I should.

When the AHJ came out and gave me a thumbs up on the roof panel install, I told him my plan for ground mounting the remaining 24 panels in the fill dirt area, and he was good with my plan to dig 2' footers and said they did not need to come out and inspect before pouring. We did not discuss grounding of the ground mount system, but I will call them to get their opinion. By having that #4 sticking up out of the concrete, I'm leaving my options open to whatever direction the AHJ would like me to take.

[tyab]

Be aware that some jurisdictions want to inspect before pouring - just make sure first before you pour.

Is that black gas pipe? I have not seen any ground systems using black pipe but schedule 40 is schedule 40 from a structure point of view.

I would also recommend tying that rebar to the vertical pipe even if you don't use it as a ufer. Check out 250.52(A)(3) for the details. If you are not putting a subpanel out there odds are your AHJ will not apply 250.52/53 to you and you only need to consider 690.47(D). If you are putting circuit breakers out there then your run becomes a feeder and then 250.52/53 do apply. And to be honest, it might simply be easier to just pound in 2 rods and call that your GE even if you have the ufer from an inspection point of view even if you do run a #4 to the rebar. In any case I would at least bond the rebar to the pipe -its there so bond it.

Looks good - you are moving right along.

[Mike90250]

if you can bond some of that rebar to the mount posts, you will have a good Ufer ground system, if the lightning rod ( that metal building next and above the array) fails !

[pclausen]

Completed the rest of the framing today, along with tying in the rebar.







Calling in an order of 14 yards Monday morning. Hopefully they will be able to come out that afternoon.

[pclausen]

Got the footer dug along with the 6 24" holes. Footer is 24" wide and between 24" and 36" deep. The 24" holes are about 5' deep (the max my post hole digger will do). Frost line is 18" in my area, so no worries there. I have calculated I need about 14 yards of concrete.







Getting that North cross-pipe exactly located and level was a pain. But it is in place now and within 1/32" in all directions.

I picked up 50 sticks of 1/2" rebar, which I plan to put down once I get the Ironridge frame all hung.

[tyab]

Nice job on the shop panels and passing the inspection. You have been busy! I went with 24" holes myself but everything I am on is cut - no fill. We have a gate around our pool and they poured some concrete for that and parts of it have cracked and settled where it was on fill.

[DanS26]

Your smart to be concerned about settling. I've seen pics of panels cracked and smashed by twisting of support systems. Up north here we see plenty of movement due to frost heave during spring thaw...got to get that foundation below freeze line.

[pclausen]

Passed inspection today with no issues. Yeah!

So now its time to get going on the 24 panel ground mount. Rather than locating it on the steep hill between the house and the shop, I decided to use the area to the left of the shop. Had to cut down 4 trees, extend the 2 gutter drains 30 feet, and do a lot of leveling. Turned out pretty nice I think.







I dragged the trees down to my burn pile about 1/4 mile away. It should be quite the fire!



I already have all the Ironridge hardware and my 3" pipe. I hope to get the holes dug tomorrow. Since the area is it going to be located at is all fill dirt from when I build the shop, I'm going to dig a footer between all the holes. And I'll dig the holes with the 24" auger instead of the 12" that Ironridge specifies. The footer will ensure that all 6 piers remain in the same position relative to each other, even if the fill dirt settles over time.

[pclausen]

Got the new EMT fittings installed and was finally able to pull my wires. Here's my pull string with a piece of plastic attached to it for sucking it through the conduit with the shop vac:



With the string in place, I next prepped the wires to be pulled. I doubled over one of the wires to give me a solid anchor point for the pull.



All done at the junction box on the roof:



Wires going into each end run connector:



And finally, the wiring at the breakers:



All I got left to do at this point is to swap that 200A main breaker for a 150A one to meet that 120% rule.