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

[Hedges]

I just moved input of fused visible blade disconnect (the AC input of my Sunny Islands) from breaker to something like a line side tap. Not really, because there is one more 200A breaker at the meter, but before the 200A breaker of the panel. This gets me away from 120% rule (70A for my panel). That's plenty for PV, but I wanted more pass-through to feed house. I can still backfeed this panel if I want to feed loads on it, but don't have to remember to switch off the breaker which used to feed the Sunny Islands and PV.

If you actually have a line-side tap, the OCP must be sufficient to interrupt the fault current utility could deliver (probably something under 22kA, which is what main breakers are rated for), and do it so fast that 10kA rated branch breakers don't get killed. Mine has FRN-R-100, which seems to have pretty decent specs. 200kA interrupting, and 10kA let-through up to 150kA fault.

https://www.mouser.com/datasheet/2/87/eaton%20corporation_01042018_Bus_Ele_DS_1020_FRN-R(7-1274763.pdf

My boxes, and Polaris connectors for splice.



I don't particularly trust that breaker, and was going to mount Class-T downstream from it. Coordinated to trip first for short-circuit, but not for overload. Couldn't shoehorn it in, and need all the space for bending wires. At least the breaker is replaceable by plug-on, with utility hot.

 

[live4soccer7]

@Hedges Thank again for the info. This will all be a tremendous help. I'll be digging deep into this stuff in 2-3 weeks. Right now I'm trying to just get the ditch inspection (been almost 10 days since I requested it) then ditches filled, and then gravel on/around the pad. Once I get there then I can start assembling the racking and really get into all the cans, boxes, etc.... and get some stuff ordered up. I'm trying to continually be working on it but not get too far ahead of myself at the same time. Right now I'm in a holding pattern and working on "spring cleanup" around the property while occasionally thinking about the electrical rack setup.

Edit: Can you pretty much add a DIN rail to any can (junction box, breaker box, etc...) or does there have to be specific mount points to follow code etc... for a DIN rail?

 

[Hedges]

I haven't seen anything restricting where DIN rail goes.
There are rules on cubic inches per wire, connection, or whatever.
Most DIN rail assembly I see has bezel so only handle is accessible to the Great Unwashed. My particular Rube Goldberg is in a box with interlocked lid, so power is off before you gain access.

 

[live4soccer7]

The inspector failed my ditch inspection because part of the ditch (120') was buried when the utility company replaced our underground power line last fall. I spent 8 hours friday night digging this up by hand. I had some words that I kept to myself for that guy. I even had pictures, pictures with measurements, etc... Blows me away that he didn't care one bit when they were doing inspections over ZOOM last year. What a waste of time.

 

[wattmatters]

The inspector failed my ditch inspection because part of the ditch (120') was buried when the utility company replaced our underground power line last fall. I spent 8 hours friday night digging this up by hand. I had some words that I kept to myself for that guy. I even had pictures, pictures with measurements, etc... Blows me away that he didn't care one bit when they were doing inspections over ZOOM last year. What a waste of time.

I can imagine you came up with whole new words with every throw of the shovel.

 

[live4soccer7]

@wattmatters Indeed. I just kept my head down, threw some music on, grabbed some waters and didn't stop until I was done. I didn't care what time it was when I finished, I just wanted to finish. It ended up being 115AM when I finally finished.

I decided to make some minor conduit adjustments with how I will run the PV wire and I added another 3/4 conduit in the ditch since it is open again. I've already requested the inspection. Last time it was 8-10 days before he came out. Hopefully he can make it out this week.

Once he approves it, I will be rockin and rolling. It will be the stabilization layer and gravel and then assembly of the PV racking.

 

[live4soccer7]

@Hedges I have the option to go with a class 200 (200A continuous) or a 320A (400A, 320A continuous) production meter. I was thinking of just going with the 320A in case I ever added more solar in through that production meter. Thoughts?

 

[onokai]

@wattmatters Indeed. I just kept my head down, threw some music on, grabbed some waters and didn't stop until I was done. I didn't care what time it was when I finished, I just wanted to finish. It ended up being 115AM when I finally finished.

I decided to make some minor conduit adjustments with how I will run the PV wire and I added another 3/4 conduit in the ditch since it is open again. I've already requested the inspection. Last time it was 8-10 days before he came out. Hopefully he can make it out this week.

Once he approves it, I will be rockin and rolling. It will be the stabilization layer and gravel and then assembly of the PV racking.

Great idea on adding another conduit -I had to hand dig a year later my 3/4 conduit in an 80 foot run to add a comunication cable that I had not planned on. Spare is always the best idea with trenches open.

 

[live4soccer7]

Yeah, my motto is pretty much, "If there's a ditch, fill it". haha. It was a little harder with this project with the price of conduit what it is. It's crazy expensive, along with just about everything.

I'm about 200-210 feet of ditch to the first array and about another 50' in between arrays. Then the arrays are about 90' long. Quite a run for the PV wires. Probably close to 400' by the time you account for elevation change, elbows, etc... for the longest run. That's why I decided to run DC all the way back instead of 240v AC. It's a bit more efficient to carry less current at higher voltages and from my understanding the voltage in panels increases quite quickly when the sun starts hitting them.

 

[onokai]

My array is about 100 feet from inverter (sol-arc) and its DC all the way
That 3/4 conduit for me last month up here(nor-Cal) was a dollar a foot

 

[live4soccer7]

@onokai That's about right. At HD and Lowes here it is about $12-14 / 10 feet. For some reason North40 had it at $7/10ft, so I loaded up there.

Have any pics of the setup??

 

[live4soccer7]

Anyone know what the proper "NEC" way would be to tap into the topside of my breaker box? I can not back feed the breaker box because it is not rated high enough, so I need to go directly upstream of the 200A breaker.

I was originally told that I could do a "meter" tap inside the meter box, but I think there must have been some sort of misunderstanding/communication. The utility company will not allow me to do this now. I will be installing a load center just after the inverters to "combine" the inverter AC outputs into 1.

Can something like this be used?

https://www.amazon.com/Polaris-Insulated-Multi-Cable-Connector-Height/dp/B00CTYR7P6

I'd just need a 3port one and then I'd need 3-4 of them to make sure I keep everything off the actual bus(es) of the panel. I'd imagine one for L1, L2, Neutral, and I'd have to tap into the main ground that goes to the grounding ROD. There is plenty of room in the panel.

Edit: The 200A panel has 2/0 wire when zooming in on the pic (bottom right Line wire).

https://media.distributordatasolutions.com/ThomasAndBetts/v2/part2/files/File_7437_emAlbumalbumsOcal20(USA)oc_1_g_nec31016pdfClickHerea.pdf

In order to properly size the inverter wire to 125%, I would need to go with 4/0 and then probably upgrade the wire/cables in the panel that go to the main meter to 4/0 as well otherwise that just doesn't make a lot of sense. I mean, technically if the utility can supply 200A then 2/0 should be good since the solar panels will supply less than 200A.

 

[live4soccer7]

@Hedges Perhaps you may know this. I found a 3 phase breaker panel to combine my AC outputs from the inverters. It is rated for up to 250A, which my 125% rule for the max output of the inverters is 237.5A.

It is 3 phase, but that shouldn't matter. I just need to hook up 240 (L1/L2/Neutral). Question is, is it still rated for 250A in this configuration? I'm not familiar with 3 phase since we don't have it at our residential location. I'd also have to make sure I plugged breakers into the correct spots, but that won't be an issue.

 

[CrazyWabbit]

you could de-rate the main breaker in that panel.
i have two 200 amp panels, and the solar installer triple tapped my meter base by adding a three lug bolt on terminal block.

 

[live4soccer7]

@CrazyWabbit

I need the 250A breaker, so I will be installing a 250A in the 3 phase panel since the rated (125%) is 237.5A. 4/0 wire (THHN) is rated for 260A, so that's what I'll be running after things are combined in the 3 phase panel. Then I will need a 250A fuse for the 400A disconnect.

I have considered hiring out the work for the connection between the disconnect and the meter base/main breaker. The utility company keeps telling me no on tapping into the meter base box (with lugs or whatever). I just can't believe that to be the case with everyone saying they are in the meter bases adding lugs etc... I think there is already a 3 lug setup in the meter base since the meter base feeds two panels in my home and one panel in the garage it is attached to. Each has its own set of wire/cables feeding the panels, so it must have a 3 lug setup already. Do they make a 4 lug???? haha.

Just some small updates. I've been busy burying ditches and working on the pad for the gravel to come in. It got cancelled last week because it rained and they deemed the field to be too wet to drive the dump trunks on. It is raining again today, so maybe by the end of next week I can bring in gravel and get that put down through the weekend. I did get an access installed to shutoff the water in the winter. I just used a septic tank riser setup. It is 3ft deep.

I have attached a pic of the panel I'm trying to get. I called the local place to "claim it" so I could come pick it up, but they are closed all week this week. One delay after another. lol.

 

[live4soccer7]

I think if I can get the solar pad shaped up this weekend the way I'd like then I'll throw down a chunk of underlayment over one of the sets of ground screws and start the rack assembly. My rough timeline is the following

1. Gravel done by end of May
2. Racking done by end of June
3. Panels installed by end of July
4. Rest of the BS finished by end of August
5. Activate system by end of September

Obviously, I'd like all of those to go quicker, but I'm trying to be realistic and with the way things have gone so far I'm really hoping it doesn't extend beyond that. Soon enough though, I will have everything needed and it'll only be my labor holding things up most of the time.

 

[live4soccer7]

Got the breaker panel I'll use to "combine" everything. He sold the 250A breaker, so I'll have to chase that down along with some 80A breakers for each inverter. Hopefully, I can get that done before the weekend is over.

 

[live4soccer7]

@Hedges Can I get your opinion?

Inverters --> 250A Panel With Feed through lugs instead of 250A main breaker with 80A breaker for each inverter --> Production Meter --> AC Disconnect with 250A Fuses --> Load Side Meter Tap (well, between meter and Main Panel, upstream of main breaker)

The 250A breaker box that I acquired only had a 175A breaker in it and the breaker bar it mounts too is only rated for 225A. I can pull this and put in a feed through kit for $120 where getting the proper main breaker and bar is about $1k. I don't really see the point of having a main breaker in there since there are no "load" breakers.

If this is an acceptable way to go about this then that's what I'll do. Trying to get this figured out asap. My head is spinning with this aspect of the project.

I have done some searching and it seems like this should be an acceptable solution. I also looked more closely at the panel I bought and it already has the feed through lugs on it. BONUS! On to finding a 400A disconnect. If I did it again, I'd probably drop the system size so I could go with the 200A gear (225A max rated). Since I'm at the 237A with the 125% rule it has pushed me to all this higher power more "industrial" stuff which has been a PIA to find at this time for a halfway decent price.

 

[live4soccer7]

Just a little update. Also trying to get gravel AGAIN tomorrow. Hopefully it doesn't rain again this evening/night.

 

[live4soccer7]

Going to start moving this over starting this evening. A little eye candy project wise and with the sunset!

131 tons of crushed granite 1-1/4" minus, roughly 93 cubic yards