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I am looking at installing a small grid tie system that can be expanded later.

Bigbillsd

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I am thinking the micro inverter would probably be the best way to do this. That way as I add a panel & micro inverter later up to the point where my wiring and breaker can handle the amperage. So I would size that wiring an breaker for the future growth.

That being said, and assuming that is something that can be done. My assumption is I should stick with the same inverters when adding on. Do I need to stay with the same panels later?

Since I will be back feeding the grid I will have to do whatever it takes from the building department and electric company. Once the initial inspection is done and up and running will I need to go thru all that again if I add another panel or two? My thoughts are I am just connecting another inverter to the same line? -Bill
 
Everything in the system will need to be sized for the future fully populated string of panels/inverters. Very easy to add on to a microinverter system; provided you don’t exceed the number of micros allowed on one 20 amp circuit, and the inverters are of the same generation (meaning only one Envoy). Better to go with IQ so u could add the Encharge battery and backup power easily at a later date (be sure to leave room for the Enpower Smart Switch).
You can use any panel that matches the specs for the micro you want to use.A53E8672-0153-4828-B2C5-46E17D0C864D.png88A4BFAE-0EB3-408B-A314-EB20CBA39FFD.png
 
That all makes sense. Looks like these MI's are 240v so they must be two hots and a neutral in the cable? (+ground?)
 
The IQ series uses the IQ Cableing which has two wires inside. Ground will need to be ran to the array. But no there is not a neutral sent to the array from the electric panel.A47D282F-97D6-449B-A446-109CA400DE95.jpeg93445B01-E49C-4A1E-A8BC-00D8DA119A94.jpeg
 
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No neutral from the MI to the breaker panel? I thought a neutral was required to complete an AC circuit? All my 240v outlets have a neutral. I guess i need to read up on that feature. Thanks, Bill
 
No neutral from the MI to the breaker panel? I thought a neutral was required to complete an AC circuit? All my 240v outlets have a neutral. I guess i need to read up on that feature. Thanks, Bill
Electrical code does not require a neutral on devices that do not use 110v.
If fully 240v, neutral is not required per 2017 NEC code. (2019 code not adopted as of yet may change this... 2014 did require neutral)
 
My electric company wanted a signed agreement for the system, including the total output. I asked the power company engineer if I could put it in an phases, since I was doing the work myself it would take a while. I am using a microinverter that has 4 ports and will handle 4 large panels. I installed 3 inverters, 12 panels, and asked them to hook me up. I had some used panels and mostly new ones, so 4 of the first 12 were the used ones as I wanted to see how good they were. Mixing them is not a problem as long as the panel open circuit and mppt voltage ratings are within what the inverter can handle. After I had all 32 of my panels and 8 inverters up and running, I was thinking about hooking up some of the used panels (growing the system a bit) so the panels would not just be gathering dust. I asked the engineer and he said we would have to have a new grid tie agreement that had the total capacity of the planned system. So it might be wise to submit a plan for all future growth and see if you can impliment in stages.

Note, I put my panels on a ground mount some distance from the house. I wanted 120v power at the site, so I did add a neutral to my run out to the panel site.
 
Electrical code does not require a neutral on devices that do not use 110v.
If fully 240v, neutral is not required per 2017 NEC code. (2019 code not adopted as of yet may change this... 2014 did require neutral)
Wow, I didn't realize things changed that radically in just a few years. I guess there is no neutral then. Unless they change it again... Hmm, if they went back to requiring a neutral would I need a different MI if it was a requirement again prior to me rolling them out. I assume once its in they wouldn't make you change it... -Bill
 
My electric company wanted a signed agreement for the system, including the total output. I asked the power company engineer if I could put it in an phases, since I was doing the work myself it would take a while. I am using a microinverter that has 4 ports and will handle 4 large panels. I installed 3 inverters, 12 panels, and asked them to hook me up. I had some used panels and mostly new ones, so 4 of the first 12 were the used ones as I wanted to see how good they were. Mixing them is not a problem as long as the panel open circuit and mppt voltage ratings are within what the inverter can handle. After I had all 32 of my panels and 8 inverters up and running, I was thinking about hooking up some of the used panels (growing the system a bit) so the panels would not just be gathering dust. I asked the engineer and he said we would have to have a new grid tie agreement that had the total capacity of the planned system. So it might be wise to submit a plan for all future growth and see if you can implement in stages.

Sounds like I tell them the max I will do and then when I implement a smaller version they will think they are in the shade all the time...

-Bill
 
I will start with the fact that I am not a licensed electrician and installed my system myself however I do have close friends that are licensed residental and commercial electricians to draw on.
I live in Texas and work with an electric co-op.
I had to submit a schematic of the system and list of parts so they could check compliance for safety.
When I installed the system, I used a SMA grid-tie inverter rated at 7700 watts.
I used 20 each Suniva 340 watt panels arranged in two strings of 10 each and had 6800 total watts but planned to 2 more panels later.
The co-op engineer said to submit it as installed and we could do an amendment to the contract later if/when I added the other two panels.
They were friendly and helpful and answered all my questions and everything was done over email except the final paperwork submittal that had to be signed and turned into local office.

After the system was installed and paperwork was done, it was time for inspection.
The same engineer that I had been working with came out and performed the inspection.
A walk around of the rack and panels and look at inverter/wiring and labeling.
He installed his VOM in the breaker panel and he said to fire it up using existing analog meter.
I powered it up and turned on breakers and main AC disconnect while he observed the meter.
After initial boot, the system did it's checks and started making power and slowed, then reversed the meter.
He threw the main breaker between meter and panel to simulate power outage and watched his VOM as it dropped to 0 volts.
He then turned it back on and watched his meter and the inverter as it powered back on and connected with grid.
He did this twice and said to turn off the system, he pulled old meter and installed smart meter, put their seal on it, handed me some paperwork and left.
That was a little over 3 years ago and I never added the extra panels but it's been cooking since and has made a little over 30 Mwh.
 
<snip>

After the system was installed and paperwork was done, it was time for inspection.
<snip>
The guy that came to my house didn't even want to look at the installation other than the disconnect beside the meter (where the AC went out to the PV field. They had told me they have no responsibility for the install, checking it, or whatever. They just want to be able to turn it off. I did note that his method to test Power Outage and auto shutdown was flawed. He put a clamp on amp meter on the line, saw it was making 14 amps, and then tripped the disconnect. Of course the amps went to zero, with the line open. I would have also put a volt meter on the AC line to the PV field to see it was zero volts. But I just kept my mouth shut.
 
The guy that came to my house didn't even want to look at the installation other than the disconnect beside the meter (where the AC went out to the PV field. They had told me they have no responsibility for the install, checking it, or whatever. They just want to be able to turn it off. I did note that his method to test Power Outage and auto shutdown was flawed. He put a clamp on amp meter on the line, saw it was making 14 amps, and then tripped the disconnect. Of course the amps went to zero, with the line open. I would have also put a volt meter on the AC line to the PV field to see it was zero volts. But I just kept my mouth shut.
many inspectors receive very little training... here in NC, I have had several ask me what they need to check...
 
I will say this guy was fairly knowledgeable about grid-tie solar installations.
We emailed back and forth quite a bit and exchanged information and his answers were on point.
Early on in the process, he pointed out resources and information and came across as more of an instructor than an inspector.
Since this is a Co-op, they are genuinely interested in helping the members and actually encourage solar installs.
This is the Bluebonnet Electric Co-op in Central Texas if any one is interested.
 
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