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

MarkSolar

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You'll need a fair bit of PV wire and connectors for your setup, I found shortages of wire when I did mine, not sure what the situation is now. Get a decent crimper for your connectors.

What did you decide to do about the line side tap, or however you are going to feed back to the grid?

Not surprised you got a better price on the Fronius, CED told me they couldn't do that good on discounting the brand but when I compared shipping cost from other places to getting it shipped free from CED, the difference was not enough to matter. But I only had one inverter, you've got 3 as I recall so the savings will be larger.
 

live4soccer7

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@Hedges

disconnect switches (if not enough integrated in inverters): There are some on inverters, but we have discussed putting them out by the panels too

Does utility require a visible-blade disconnect? Yes, I need an AC disconnect that can handle 200A AC

Surge arrestors (e.g. Midnight): This? https://thepowerstore.com/midnite-solar-spd-300-ac-surge-arrestor-with-flush-mount-box.html

Grounding - does the rack take care of that (WEEB)? Or do you need lugs to lay a wire in? Taken care of on racking

MC wires/pigtails/Y connectors: Not quite sure what I'll all need here. I'm thinking I should just need a connector for the end and beginning of each string (6 strings).

Combiner boxes? (If inputs to Fronius aren't sufficient and you're paralleling more than 2 PV strings.: I'm not paralleling any DC strings, but I'll need to combine my AC outputs from the 3 fronius inverters, perhaps I can do this in the junction box that the utility company wants because they will be tapping directly into the meter base as opposed to backfeeding my main panel due to the power output of the system (187A 240V Theoretical Max)

I suppose Fronius is transformerless? Does it contain the required fuses for both ends of PV string? (Last I heard that was needed for transformerless, but my experience is with decade old equipment.): This, I have no idea. Perhaps someone else has experience?

If you use wire nuts anywhere, I like "Ideal" set-screw wirenuts: I assume you're referring to these: https://www.homedepot.com/p/Ideal-Set-Screw-Wire-Connector-for-Model-22-100-per-Box-30-222/305259920 I might need something else. It says 600v max on building wiring and 1000v max on "sign" wiring.

@MarkSolar The fronius are $450 less PER UNIT. They are going to tap into the meter base and it will then go into a junction box.

I'll be buying all this stuff at the beginning of DEC. I can't spend anymore money on my card this month as it has a monthly spend limit. lol.
 

Hedges

I See Electromagnetic Fields!
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Three Fronius each needs suitable AC fuse or breaker. A single fused disconnect would be too high a current for the max fuse required by the inverter.

I cut short MC cables to make pairs of pigtails where I make transition from PV string to wire in conduit. Double & triple check polarity. Confirm correct at inverter DC disconnect before turning on switch. If multiple PV strings get paralleled inside inverter (more than one string per MPPT), confirm near zero volts between MC cables before mating. (DMM may show voltage that leaks down due to some capacitance discharging.)

The transformerless and fuses issue would be described in manual if needed. I think the idea was failure of transistors could cause DC from PV to enter grid and its transformers.

Yes, that's one of the surge arrestors. That one appears to be for 120/240VAC. Others are available for PV (only surge in PV is nearby lightning, except in the case of zombie apocalypse.)
 

live4soccer7

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@Hedges Thanks! I'll have to do some more reading and research on what you provided so I can get the correct items/materials. I'll post up again once I've got a better grasp on it.
 

wattmatters

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Combiner boxes? (If inputs to Fronius aren't sufficient and you're paralleling more than 2 PV strings.

I suppose Fronius is transformerless? Does it contain the required fuses for both ends of PV string?
Neither will be required with this set up.

what else I'll need to snag
A few thoughts, ignore whatever make no sense for you :)

Wire cutters and strippers
Zip ties (metal) and cable clips (some clips may come with the panels - to hold cables neatly)
Clamps for the panels - right type and number of each?
Cable
Depending on your cable and personal preference on terminal connections you may want a ferrule kit.
Conduit and connectors
Conduit saddles
Solar DC warning tape for cable trench
Solar PV Label kit as required for local code spec

Here we have to have certain specific labels on the main circuit board or any sub-board energised by solar PV (big round green "PV" and sundry warning labels), labels identifying the inverter's AC circuit breakers, one on the inverter advising of the shutdown procedure, "Solar DC" labels on any visible conduit carrying PV DC, "PV array isolator" label on any DC isolator.

Sort of like this but whatever makes sense for your local codes:
KNS01.jpg

Screen Shot 2021-11-20 at 6.05.07 am.png
 

live4soccer7

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@wattmatters Thanks and TON. All of this helps whether you think it is known or not. At the very least the "obvious" things help jog my memory of things I need. I'll go through all of this information and start putting my purchase list together over the weekend. I'm sure I'll have more questions about things for everyone before the weekend is over. haha
 

wattmatters

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I forget where you got up to with using a Fronius consumption meter with your system (I think it's really valuable to have for complete monitoring) - that will need data cable to connect to the inverter's data manager, and you'll probably also need to connect the inverters together as well. I'm a bit hazy on the specific requirements.

Drills and bits suitable for creating the holes needed to push conduit connections through walls or circuit board enclosures, and appropriate means of sealing (glands, dektite, silicone etc whatever makes sense for your set up).
 

live4soccer7

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I'll have a Ethernet cables extremely close to the inverters, so that won't be a problem at all. The datamanager is built into the inverter and different than the "smart meter", correct? I'm not sure if the smart meter will really be able to work for me since it is a "clamp" that would go over the AC lines. I watched a video and it seemed you would put those clamps over the lines that feed your house "AFTER" the AC lines from the PV system (if that makes sense).

I have 3 panels on the property, so I'm not sure how much value I would get out of it since I probably can't connect them at a junction that would be beneficial at reading everything since I won't have access to the inside of the meter box and that is where the junction would be for everything (grid and PV power).
 

wattmatters

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The meter is a different type I think in US than here.

And yes the meter usually sits at/near the point of grid supply and connects to the data manager card inside the inverter. The can be in the feed-in path or the consumption path.

But you'd have to check the wiring diagrams for the kind of meter used in USA. Ours are a different type.

If ever you need to export limit, you will need a consumption meter.
 

live4soccer7

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Here's to hoping the utility company doesn't change their rules on me within the next 10 years so I can let er run full bore and get ROI. lol
 

live4soccer7

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small update: I've got the "grid" staked out and I'm just waiting on the augurs to come in. I should be ordering up the inverters and wire either this week or next. Not much to update at this time and nothing fun, ie photos.

If their initial estimate of "within two weeks" is correct then I should be able to get augurs and install them this weekend. I'd be surprised though if they came in on time.
 

live4soccer7

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I was hoping I could get away with 1500' of each wire, but my "generous" calculation for wire was 1512' for each. Gonna have to round up since I know that doesn't ever work out perfectly due to spool sizes. 2 x 1000' spools of each it is.
 

Hedges

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Are your trenches done already?
Cutting a corner would be less length than a 90 degree angle. And two 45's is easier to pull through than one 90.
 

MarkSolar

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I have a tape that you pull through the conduit and it has measurements on it so you can get the length more accurately.
You also might be better off buying by the foot at a local supply house.
You could buy 1000' bulk and then measure again to get the final length. Buying an extra 500' of each cable is a lot of extra money and it will be setting in your shop for the next 20 years.
 

live4soccer7

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I don't see why it couldn't be used for anything else "house wise" (120/240v circuits) that you would want to wire with 10 gauge. Well, when you're running it in conduit. I have a few things I could definitely use it for and I will be doing a shop down the road, funds permitting. I think I'll end up using it all without a problem.
 

live4soccer7

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Are your trenches done already?
Cutting a corner would be less length than a 90 degree angle. And two 45's is easier to pull through than one 90.
There are no 90s except the elbow that goes into the ground and out of the ground. Knowing that I'll be able to use it for other things, I'm seeing if TPS can get spools of 2500'. This is a standard spool size for this size wire, talking with my electrician friend.
 

live4soccer7

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Any recommendation on "dual pass" vs "single pass" pv wire? The wire I've been quoted for is single pass from the powerstore.
 

MarkSolar

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If it's in conduit I'd save the money and get single pass. If it's going to be exposed to sunlight and possible outdoor mechanical abrasion I'd go dual pass. The only difference is in the extra layer of insulation.
 

live4soccer7

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@MarkSolar Thanks! It'll pretty much all be in conduit except probably a tiny bit where it would go to the panels from the rack/frame.

Strangely, they quoted me less for dual pass a week ago. I called them out on it and seeing if I can get the dual pass they quoted me on last week. Getting quotes and pricing from these companies is truly a chore. They probably ALL hate me. But hey, I am paying out so....... they have to like that. This should be the last major purchase, so I can hopefully quit hounding all these companies. The last bit is the panels, but I've already locked those in.

I have a hydraulic head lined up for Friday and I will be getting 12-13 ground screws from CED friday. I will be attempting to throw those in the ground as a preliminary run before the majority show up in a couple weeks. Here's to hoping they go in well. Fingers crossed and hands together. lol.
 
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