diy solar

diy solar

Finally, the start of my 25kw Ground Mount grid-tie system

Any ideas on who I could contact to pile drive the "C-Piles" from the Unirac GFT system? I have three calls/emails out to people today for different solar related things and didn't hear back from a single one. Getting quite annoying and slowing down my process.
 
I'm unable to find anyone in the area that will pile drive the C-Piles and the cast in place (concrete) for the GFT system would cost me about $3200 between concrete and sonotube, plus a bunch more time and inspection. That would make the system a wash on price, at best.

Looks like back to sunmodo. The one good thing about the sunmodo is if I did ever want to move the array if the utitility company did something crazy then I could "unscrew" the posts and completely move the array for a different orientation. It would be a pia, but at least an option as opposed to completely scrapping the posts, which the c-piles would be about $2000-2500 for 10 of them. Not to mention setting them again. IDK, trying to just look at the positive aspects of the sunmodo system.
 
What is the thick rubber tarp looking material you see some of the ground mount systems use on the ground under the rock? Other than "weed guard fabric" lol
 
I submitted everything that I have to the county for a permit today. I do have to do some department of ecology report/checklist thing. Such a waste of time. Hopefully the ball will begin rolling now.
 
Ecology report submitted. Just have to wait and look into the electrical permitting in the meantime. I feel like the electrical permit should be pretty trivial at this point with all the documents and drawings I've created.
 
It's looking like 5/8" minus basalt will be the choice of ground cover. Talking with a neighbor, crushed concrete usually contains a decent amount of metal and can cause flat tires etc.... Definitely not going down that road since I'll likely be driving my little tractor over this area somewhat often.
 
SonoTubes: I just used 55 gallon drums below grade. Two of them with tops and bottoms cut out and then tack welded together made for really nice sonotubes.
I did use some short sonotubes above grade just for appearance.

Crushed Concrete: There are metal fragments in the crushed concrete but its not nearly as bad as it used to be in the old days, but the problems are still brought up about it even though they are mostly taken care of. I brought in 30 tons for my driveway and ended up with about 1/2 a coffee can and not a flat tire yet. You just need to walk down the path, kick some of it around, and look for the pieces. We spent about an hour doing it and no problems.
Also, the type of flat tire that the concrete rebar pieces cause, if it does happen, are easily fixed with a simple hardware store plug.. Don't even need to take the tire off.
 

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I thought about the barrels, as you mentioned it previously. It'd be about $15 a hole plus probably another $10 for a foot of 24" sonotube. I'm still looking at about $25 a whole * 20 holes. Let's just call it $500 + concrete. That's if the inspector let's me do it that way. I don't see why not, but ya never know.

I'll probably just go with basalt. The crushed concrete would probably be a hair better for a "reflective" surface.

I submitted the permitting plans with the sunmodo system.

Everything is still in review and pending. It is possible I could hear something next week, but unlikely.
 
@SteinVT How did you work the grounding on the sunmodo system? Are all the panels "self-bonded" by the panel mounting clamps so that you only really need to ground the frame from one point?
 
Looking at NEC, I should be able to ground the PV arrays with a grounding rod instead of having to ground it all the way back to the inverters.
 
live4soccer7 said:
Looking at NEC, I should be able to ground the PV arrays with a grounding rod instead of having to ground it all the way back to the inverters.
Click to expand...
An auxilliary ground rod can't be used as a ground fault current path (2.50.3.5). You need a ground path that will conduct enough current to cause an overcurrent protection device somewhere to trip. So my understanding of the code is that its allowed to add an auxilliary ground rod, but an auxilliary rod is not allowed to take the place of the required path to ground that ultimately ends up bonded to neutral in your service panel.
 
Update: Permit passed the first department and they signed off. Hopefully just a few more to go.
 
I got hit with the requirement for WA engineer stamps on the sunmodo drawings. A quick call to sunmodo and they have them for most states:

Knowledge Base - SunModo Knowledge Base

knowledgebase.sunmodo.com knowledgebase.sunmodo.com

Scroll down to:

Ground Mount Stamped Documents - US​


That call saved $300 from vector engineering, hopefully.
 
live4soccer7 said:
@SteinVT How did you work the grounding on the sunmodo system? Are all the panels "self-bonded" by the panel mounting clamps so that you only really need to ground the frame from one point?
Click to expand...
I also have Sunmodo, yes the mounting structure and panels are bonded because the mounting hardware all incorporates WEEBs. Sunmodo provides a ground lug that attaches to one of the rails, you use it to ground the entire system.
 
@MarkSolar From the looks of it, I will need to run a ground wire down the entire length of the Ground Mount system. Is this correct?

Assuming I can't use a grounding rod, which it sounds like I can't, anyone know how to calculate the size grounding wire I will need for the entire system? This kind of sucks since it I will need about 100ft for each ground mount array and then I'll need another 175' or so to get back to the inverters. Unless there is another way to go about that. I'm sure I could use a little smaller gauge for the individual arrays and then something larger to get back to the inverters.
 
live4soccer7 said:
@MarkSolar From the looks of it, I will need to run a ground wire down the entire length of the Ground Mount system. Is this correct?
Click to expand...
No, you can put the array ground lug right next to the combiner box, or wherever it's most convenient to connect to your ground conductor. I put my ground lug about 3' from the combiner box.
live4soccer7 said:
Assuming I can't use a grounding rod, which it sounds like I can't, anyone know how to calculate the size grounding wire I will need for the entire system? This kind of sucks since it I will need about 100ft for each ground mount array and then I'll need another 175' or so to get back to the inverters. Unless there is another way to go about that. I'm sure I could use a little smaller gauge for the individual arrays and then something larger to get back to the inverters.
Click to expand...
The size of the ground depends on how or if you've fused your DC conductors. If you've used fuses, the ground conductor would be sized based on the current required to blow the fuse. If you didn't use fuses, the ground wire will probably need to be the same size as the current carriers.
 
MarkSolar said:
The size of the ground depends on how or if you've fused your DC conductors. If you've used fuses, the ground conductor would be sized based on the current required to blow the fuse. If you didn't use fuses, the ground wire will probably need to be the same size as the current carriers.
Click to expand...
I haven't necessarily determined this aspect yet.

Each "String/Series" has a Pmax (Impp) of 10.83A and a Short Circuit Current (Isc) of 11.47A

There are a total of 6 series (16 panels each).

hmm..........

If I grounded each array "Individually" (48 panels) that would be a Short Circuit Current of 34.41A per array (11.47*3) or a combined current for the whole system of 68.82A.

Could I fuse each ground mount array (3 x16 panels)? So there would be two fuses (one for each 3x16) or would I have to separate out the series in each array somehow?

I guess not being familiar with this aspect at all, so any and all input is definitely welcome.
 
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