Solar for a new house

iamrich

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Elgin, Texas
Been playing around with ideas for my (soon to be built?) house. I think I am close on the plan, but the components are still up in the air. Not sure if I can get Growatt grid tie approved with my provider. Any comments welcome. The main grid tied panel will be non-essentials, and the two sub panels will be essentials. It is a single house with two living areas (approx 2400sqft ranch 40'x60'), Central Texas, South West facing roof (211°) 27° pitch, 5 hours of sun. 40-50kwh usage per day.

Solar Array 004.jpg
 

sunshine_eggo

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You'll need UL1741 listed inverters
UL1741SA for grid-tie

Likely can't get house insurance without them.
 

iamrich

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Yeah I am a little fuzzy on that as my county is IBC2006 with zero inspections of any kind other than OSSF (Septic). I think it will come down to what the electric provider will allow and even that will only apply to back feeding the grid. I already have 200amp service and a normal (digital) meter, so I would need a net meter to back feed. I guess I need to make some phone calls. One of my neighbors already has a grid tied system, so I might just pop over there and see what he has and what he had to go through to get it.

My main concern (unknown?) is if the 6kw inverters can power the sub panels reliably. I picked the transformer versions to handle surge.
 

Shinebox

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Feb 10, 2021
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Yeah I am a little fuzzy on that as my county is IBC2006 with zero inspections of any kind other than OSSF (Septic). I think it will come down to what the electric provider will allow and even that will only apply to back feeding the grid. I already have 200amp service and a normal (digital) meter, so I would need a net meter to back feed. I guess I need to make some phone calls. One of my neighbors already has a grid tied system, so I might just pop over there and see what he has and what he had to go through to get it.

My main concern (unknown?) is if the 6kw inverters can power the sub panels reliably. I picked the transformer versions to handle surge.
The point about insurance still stands though, regardless of how lax your county is. You’ll likely be able to get it, but in the event of a fire or something, you can bet that they’ll use the lack of a UL listing to wriggle out of taking care of you, regardless if the fire has anything to do with your inverter.
 

Quattrohead

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Oct 13, 2021
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If you want to run with no grid feed back that would be the easiest solution. It sounds like grid feed back is possible with your PoCo but things may have changed since your neighbor did it. Your diagrams look good and I like your components.
However, this whole "you'll shoot your eye out kid" if you don't use UL listed equipment is not true.
 

Shinebox

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If you want to run with no grid feed back that would be the easiest solution. It sounds like grid feed back is possible with your PoCo but things may have changed since your neighbor did it. Your diagrams look good and I like your components.
However, this whole "you'll shoot your eye out kid" if you don't use UL listed equipment is not true.
That’s not really my point. I have nothing against Non UL listed equipment, I was just pointing out how insurance companies tend to operate.
 

Quattrohead

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That’s not really my point. I have nothing against Non UL listed equipment, I was just pointing out how insurance companies tend to operate.
Try having a few rental properties in Florida, then you will know how they operate !!!! Bastards.
 

iamrich

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994
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Elgin, Texas
If you want to run with no grid feed back that would be the easiest solution. It sounds like grid feed back is possible with your PoCo but things may have changed since your neighbor did it. Your diagrams look good and I like your components.
However, this whole "you'll shoot your eye out kid" if you don't use UL listed equipment is not true.
I was leaning towards off grid completely, but with a planned 18kw of panels, I just don't think I will use all the power they produce. I hate to waste it, which is what I am doing with my current 2kw array on the garage. Back feeding the grid will at least cover my grid usage, I think.
 

iamrich

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Elgin, Texas
Confirmed with my electric company that they are NEC 2020. Interesting thing is that the person I talked to confirmed that the inverters must meet UL-1741 standard, but don't have to actually be UL listed. All the Growatt units above are listed on the Intertek ETL website as meeting UL-1741 standard. My next plan is to just draw up all the stuff above with model numbers and links and just submit it for review. Will not cost me anything other than my time. I guess I could always pick another grid tie inverter that has UL listing, but that doubles/triples the price for no added value.

There is also conflicting info about the homeowner being able to do the work and having to use a licensed contractor. This should be a fun adventure :p
 

sunshine_eggo

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Confirmed with my electric company that they are NEC 2020. Interesting thing is that the person I talked to confirmed that the inverters must meet UL-1741 standard, but don't have to actually be UL listed.

This is in conflict with NEC 2020. I would get it approved in writing.

All the Growatt units above are listed on the Intertek ETL website as meeting UL-1741 standard. My next plan is to just draw up all the stuff above with model numbers and links and just submit it for review. Will not cost me anything other than my time. I guess I could always pick another grid tie inverter that has UL listing, but that doubles/triples the price for no added value.

There is also conflicting info about the homeowner being able to do the work and having to use a licensed contractor. This should be a fun adventure :p

Many states have some sort of provision for DIY. It usually involves some dollar threshold. Here in AZ, it's "less than $1000." In that case, you itemize down to the level that you keep each task to below that level.
 

iamrich

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Elgin, Texas
Interesting...

Not sure if this is worth the internet digital paper it is written on, but https://www.righthandindustrial.com...d-ahj-in-industrial-electrical-installations/

“Listed” is a term found in some but not all codes and standards in the NEC. Keep in mind that “listed” does not mean “UL Listed” nor does it mean the product has been “approved”, both common misconceptions. The term “Listed”, according to the NEC means that the equipment, materials or services are included in a list published by a Nationally Recognized Testing Laboratory (NRTL), a private-sector organization appointed by the Occupational Safety and Health Administration (OHSA) to perform evaluation, safety testing and certification of products, using consensus based test standards, for safe use in the workspace.

A bunch of the Growatt stuff is on the Intertek listing: https://ramuk.intertekconnect.com/W...e5946df8a131d0d2862587ae002a85f8?OpenDocument


No harm in submitting the build plan to my provider...
 
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