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diy solar

diy solar

Update: 35KW ground mount system added to existing 3kW rooftop solar in Phoenix, AZ.

In my drawing, I am missing the 200A fuse before the disconnect.

The wire inside the 200A disconnect going to the basement panel is 3/0 awg.

Here are the two fused disconnects at that outside service panel:
1723248128794.png

1723248144915.png
1723248274397.png

1723248246663.png
 
I'm guessing (because I can't be sure) that the 400a pull out disconnect is the main? (Which suggests that you have a 400a service)
And are currently only using one 200a pull out disconnect for the house?
Which tells me that you can definitely use the spare disconnect for all of your PV production. This would also allow you to get rid of the existing PV disconnect. Because the pull out will have that covered.

But you need to verify everything with your engineer and utility company.
 
I'm guessing (because I can't be sure) that the 400a pull out disconnect is the main? (Which suggests that you have a 400a service)
And are currently only using one 200a pull out disconnect for the house?
Which tells me that you can definitely use the spare disconnect for all of your PV production. This would also allow you to get rid of the existing PV disconnect. Because the pull out will have that covered.

But you need to verify everything with your engineer and utility company.
Here is the schematic that is in the house plans (thankfully they came with the house when I bought it)

1723256103203.png
Solar specific schematics
1723256198013.png
Current calculations
1723256157058.png
 
So, the 400a pull out is for another panel on the first floor (panel A).
And the 200a pull out is for the basement panel (panel B).
This is a little trickier, because you already have 600a worth of disconnects in your 400a service panel.
Which in itself isn't necessarily a problem. But means that load calculations are important. I think that you're better off getting help from someone that can look everything over in person.
It's getting outside of my comfort zone, over the internet with only pictures to go on.
 
So, the 400a pull out is for another panel on the first floor (panel A).
And the 200a pull out is for the basement panel (panel B).
This is a little trickier, because you already have 600a worth of disconnects in your 400a service panel.
Which in itself isn't necessarily a problem. But means that load calculations are important. I think that you're better off getting help from someone that can look everything over in person.
It's getting outside of my comfort zone, over the internet with only pictures to go on.
ok, I appreciate the input nonetheless. It does seem to be throwing my permitting guy for a loop as well. He said this afternoon that he's going to get me preliminaries. He said it might require "PE" stamps? He said he knows people that can do that, but he's not able to do that himself.

This whole thing is a learning process for sure.
 
ok, I appreciate the input nonetheless. It does seem to be throwing my permitting guy for a loop as well. He said this afternoon that he's going to get me preliminaries. He said it might require "PE" stamps? He said he knows people that can do that, but he's not able to do that himself.

This whole thing is a learning process for sure.
Please let us know how it all works out.
I'm sure that there is a simple solution. It's just hard to see from this far away.
 
PE = Professional Engineer (I think this encompasses all licensed engineers, EE and structural may apply to this project) stamps depend on whether your AHJ / POCO require it.

I think what you're running into here is, installing a rather large DIY system on a service setup that is at the edge of what is common on this DIY forum, and just outside what you can find articles explaining it. For instance I self-designed and installed a 17kW-AC system on a 100A service, which allowed me to avail of some simplifications not available in your situation.

I don't trust the plans to say what the busbar rating is on the service disconnect, versus having a part number / picture of the wiring diagram on the equipment itself. The two sets of plans disagree anyway.

If the 200A lug fed subpanel is convertible (IE can accept a main breaker), then main breaker would definitely allow solar tap to go into the same 200A disconnect. And you can kind always replace that subpanel with a convertible one. 200A convertible is usually not expensive, like $100-150 with the breaker.

Looked at the photo of the top of the subpanel. I don't think a main breaker can dock in the lugs at that place.

This stuff isn't exactly rocket science, but it's not been super efficient/reliable to go back and forth on this forum. Maybe you can see if a professional is willing to VC with you? Then they can tell you things like, "move the camera 2 feet to the left so I can see the wiring diagram", "pull that thing out".
 
Just in the event that anyone was curious, I was able to get approval for construction from my utility after 4 revisions to my plans. Phoenix Fire also approved them. I'm now waiting for City of Phoenix. My utility is SRP (Salt River Project). This may help someone else going through this process.

Here is what was landed on:
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1726082116189.png
 

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