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

[pclausen]

I got the junction box drilled. Only issue is that the plastic sidewall is too thick to allow both the lock nut AND bushing to fit on at the same time. So I can either do this:



Or this:



Problem with using just the bushings is that I can pull out the connectors without much force. Problem with using just the lock nut is that you are supposed to also use a bushing, Perhaps I can glue the bushings on?

Also worked on the grounding for the arrays. There are 3 physically separate arrays (due to metal expansion). All 3 are being grounded to the main metal building ridge plates. I grinded the paint off in the areas I would be making contact.



And here are 2 #6s going to one side of the roof. The 3rd array will be grounded in a similar fashion at the opposite end of the roof.



The temptation was too great to not go ahead and connect the panels temporarily (running 12-4 cable I had laying around from each string down into the breakers. Still have a few panels not working yet, but I was making just under 10kW around noon.



My meter transmit usage back to the POCO on a daily basis. I confirmed that it has been running backwards for the last few days. No usage at all. Hehe.



Once I'm official and get the current meter replaced with a net meter, I suspect I'll be able to see consumption vs. whatever I push into the grid.

So far I have pushed 180kWh back into the grid (less whatever I used).

[MULINS22]

I kind of have my own question but i donot know where to post it?

[tyab]

EMT into a plastic box just requires the lockring - the bushing is what you use if you have wires coming out of EMT in free air. Hopefully your EMT has an insulated throat so there is no risk of scraping the wires.

I have lots of pictures of insulated throat EMT connectors here (most are yellow and a large one is green)


You are going to need two grounds and they are not the same - they are considered separate. The EGC ground (green) wire from your microinverters and it can tie to any structural metal along the way (and should) if that metal is used as part of the EGC (for example, EMT conduit that is strapped to a metal support or metallic junction boxes). The 2014 code also requires a GEC ground and it is covered in 690.47(D). Review that section carefully and it requires that 250.52 be followed for that ground - and there is an exception allowing structural steel but you will need to read that carefully. Be aware if you see the term "continuous" there are very special requirements for that.

Looks good so far, I'm busy myself getting rails up.

Admin note I removed the link, please dont link to that site, cheers.

[Mike90250]

I know, metal frame, metal roof, metal everything. I still don't like inviting lightning strikes indoors to ground.
And did you polish paint off between beams, or relying on the bolts to connect the metal ?

[pclausen]

So the EGC green wires from the microinverter strings will land on the ground bar in the plastic junction box like so:



And a single green ground wire will run in the conduit to the ground bar in the breaker panel.

The GEC from each physical array is what is tying into the metal structure.

When I built the metal building 15 years ago, the LHA has me tie all the metal members together with #4. So I made the assumption that he would be ok with me using any metal of the building as a GEC conduit. I guess we'll see how picky he is. If me makes me run #6 from each of the 3 physical arrays to the ground rod, so be it. It will take about 200' to do so. I'm hoping to avoid that, but it is really not that big a deal if he makes me.

Given that #4 is used to tie some of the structural members together, it might be that they are not considered continuous and I have to do the 3 individual 75' runs to the ground rod. I'll check out 690.47(D).

[foo1bar]

Here's where it drops into the panel.

Are you planning to use the 120% rule?
Because it looks like you've got a number of strings, and will have multiple breakers.
And my understanding of the 120% rule is you only get 1 breaker at the opposite end, not 3 or 4.
But I can't see how it'd be a safety issue, so if your AHJ is OK with it I think go for it. If they do have want everything combined before going to the backfeed, then it should be easy enough to add a panel next to your existing one. And combine everything in that new subpanel.

[foo1bar]

I kind of have my own question but i donot know where to post it?

You can click on the "Solar Panels for your Home, Grid Tied Solar PV"
and then "+ New Topic" to add a new thread under grid-tied section.
If grid tied isn't the right section, find the right section and add a new thread under there.

[pclausen]

Are you planning to use the 120% rule?
Because it looks like you've got a number of strings, and will have multiple breakers.
And my understanding of the 120% rule is you only get 1 breaker at the opposite end, not 3 or 4.
But I can't see how it'd be a safety issue, so if your AHJ is OK with it I think go for it.

Yes I plan to use the 120% rule. The 200A main breaker is being replaced with a 150A one. So 200 * 1.2 = 240A - 150A = 90A. With 4 20A breakers, I'll have 10A to spare. My AHJ said that as long as I had space for the PV breakers in the main panel, he was ok. He didn't even mention the 120% rule. Keep in mind that I live in a rural county in Virginia and the entire AHJ department consist of 3 people. My permit number is 311-2016 and was pulled in August, so they have maybe 400-500 total permits for 2016 and there might be a few others related to solar panel installs.

[pclausen]

The 2014 code also requires a GEC ground and it is covered in 690.47(D). Review that section carefully and it requires that 250.52 be followed for that ground - and there is an exception allowing structural steel but you will need to read that carefully. Be aware if you see the term "continuous" there are very special requirements for that.

I read 250.52 and I don't meet that to the letter regarding the continuous reference. That said, I'd say there's a 50/50 chance the AHJ will be ok with the way I did it. Like I said, running individual #6 from each of the 3 arrays to the ground rod is not that big a deal. Technically, the entire shop is a subpanel location from the main house and this only has a single ground rod (I do have 2 at the main house). Not sure if that plays into it. We'll see what they say.

[tyab]

I live in a rural area also and I have found our building department to be very helpful. When I have a question - I give them a call and so far I have gotten clear answers. I would give them a call and ask about the structural metal and use of a GEC and in particular with 690.47(D) and ask them if they will accept what you are doing or if they want a separate #6 run. 690.47(D) is a mess in any case, here is a good video on 690.47 and goes into the issues with (D). Note that 690.47 was reworked in the 2017 NEC, (D) was renumbered to (B) and is now optional.

https://www.youtube.com/watch?v=Ypo99VRxT44

Here is what insulated throat EMT connectors 3/4" look like (these are yellow). According to code they are NOT required unless you are using #4 or larger wire but not a bad idea given they are only slightly more expensive than the not insulated EMT connectors and give a margin of safety against damaged wire when pulling.

[pclausen]

Very nice job on the ground wires!

They look awfully similar to what I just got in today.



The ones I'm currently using are not rain-tight at all, even though the guy at the counter at tri-state electric was trying to convince me they were, as long as I made them real tight. I called them ahead of time and they assured me what they had was rain-tight. Drove 45 mins. Was pretty pissed when he showed me what he had. A couple of other electricians at the counter said those were also what they always used outdoors. They were cheap, so I picked them up. Anyway, that is why I have been procrastinating puling the #10 wires.

Thanks for the link to the real deal!

Thanks for the Mike Holt video. Never actually seem him live before.

And yes, my building dept. has been great to work with as well. There as some things however, like my particular shop building, the he would have to come out and see in person to make a call on the GEC "stunt" I'm trying to pull.

I'm going to a meeting at the local community center later this week. It is hosted by the POCO and will feature heavy appetizers and drinks. The meeting was requested by several members who have photo-voltaic generation at home and thought that an ongoing conversation with their cooperative and with other renewable generation members would be helpful.

President and CEO will lead the discussion, providing an overview of where the POCO is with their solar distribution project and with the community solar garden project as well as a quick summary of the specifics of the Net Energy Metering Rider, which is based upon language provided by the State Corporation Commission. Should be very interesting and I applaud them for reaching out to their members like that.

[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.

[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.

[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.

[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.