Amateur doing a 10kw system, can someone tell me if I missed anything

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  • solar_dave
    solar_dave Solar Expert Posts: 2,397 ✭✭✭✭
    #62
    Re: Amateur doing a 10kw system, can someone tell me if I missed anything
    SkiDoo55 wrote: »
    Not without downsizing your main breaker if allowed.

    40 Amp is the MAX backfeed allowed on a 200 amp main panel

    The Fronius 75 would be at MAX allowed backfeed

    That is the Combined backfeed of all inverters.

    Agreed, the 7.5 is maxing out the possible back-feed with the known current main breaker and assumed 200 amp buss bar sizing.

    You can downsize the main breaker to get some headroom, if the AHJ allows it with your current load.
    Mine did not and it got expensive to get my 12.5 KW system installed, as in a major service entrance upgrade.
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  • DanS26
    DanS26 Solar Expert Posts: 269 ✭✭✭
    #63
    Re: Amateur doing a 10kw system, can someone tell me if I missed anything

    It would seem you will be much better off design wise and cost wise to expand the main structure to accommodate the extra six panels. The roof mounts and micro-inverters costs can then be avoided. Just extend the rails to accommodate the extra row.

    IronRidge has a design tool that could help. See here: http://www.ironridge.com/gm

    Also, per the Fronius manual the 10.1 inverter has to be protected by a 60 amp OPD. That means if you have a typical 200 amp residential service, the main breaker will have to be derated. If this is confusing then you need to employ a qualified electrician familiar with grid tied solar installations. He will also be able to determine wire sizing and conduit fill.
    23.16kW Kyocera panels; 2 Fronius 7.5kW inverters; Nyle hot water; Steffes ETS; Great Lakes RO; Generac 10kW w/ATS, TED Pro System monitoring
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  • WhittakerJ
    WhittakerJ Solar Expert Posts: 67 ✭✭
    #64
    Re: Amateur doing a 10kw system, can someone tell me if I missed anything

    Guys, thanks for all the information yesterday.

    Is there a simple tool for determining whether or not my electricity consumption will allow me to derate my main breaker to 175a? I believe this would allow my maximum breaker size to be 65a, correct? Which would be enough for my installation.

    My house is pretty basic:
    2056 sq ft
    5 ton ac/heater
    2 story
    Electric range
    Electric fridge
    Electric microwave
    Electric dryer
    95% of my lighting is LED so there is little consumption there.
    Gas water heater

    I guess I'm just trying to figure out if there is an easy way without going through all my appliances, trying to find the model, and then trying to find the amperage.

    If it is determined that it is possible to derate to 175a is it as simple as shutting off the supply side of my electric box and simply removing the two screws and replacing it? Or does this require some type of approval from SRP?

    My electric box is here if this helps determine.

    Attachment not found.

    Man this electric box is filthy! I should spray it down with the hose later!
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #65
    Re: Amateur doing a 10kw system, can someone tell me if I missed anything

    Mega-power users: 5 ton A/C, electric range, electric dryer.

    I can't remember the exact derating used (I'm sure someone here can) but there is a formula like "total of circuit breaker Amp rating * (number can't recall) = main breaker rating". This is for quick-estimating and does not necessarily hold up against an AHJ.

    Other things to check: can you actually get a 175 Amp breaker for you main? Will the AHJ understand the derating? And the back-feed breaker size will probably be 60 Amp (available) not 65 but the principle is the same.

    And I sure hope you were kidding about hosing it down. :roll:
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  • DanS26
    DanS26 Solar Expert Posts: 269 ✭✭✭
    #66
    Re: Amateur doing a 10kw system, can someone tell me if I missed anything

    You come across as a DIY type guy. Nothing wrong with that. If you are going to DIY with electrical systems, then you have to become familiar and even intimate with the NEC code relevant to your area and relevant to solar installations. If you are not willing to invest the time and effort to safety install these systems, then hire an expert.

    Changing a main breaker is NOT a DIY project. It is NOT just "a couple of screws".

    We are willing to help you. But we do not want you to get hurt or worse for your family.
    23.16kW Kyocera panels; 2 Fronius 7.5kW inverters; Nyle hot water; Steffes ETS; Great Lakes RO; Generac 10kW w/ATS, TED Pro System monitoring
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  • solar_dave
    solar_dave Solar Expert Posts: 2,397 ✭✭✭✭
    #67
    Re: Amateur doing a 10kw system, can someone tell me if I missed anything

    So SRP might be able to help you with the needed calculation for the derate. They have to approve the interconnect, I would call the Mesa building inspector/code guys as well. You can get a 60 amp breaker to do what you like I think, you AC combiner panel will have a 40 and 20 amp breaker in it and that will dictate a 60 in the main panel.

    A main breaker change out usually requires a meter pull to deaden the line and remove the seal, SRP can do that for you when you are ready.
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  • WhittakerJ
    WhittakerJ Solar Expert Posts: 67 ✭✭
    #68
    Re: Amateur doing a 10kw system, can someone tell me if I missed anything
    DanS26 wrote: »
    You come across as a DIY type guy. Nothing wrong with that. If you are going to DIY with electrical systems, then you have to become familiar and even intimate with the NEC code relevant to your area and relevant to solar installations. If you are not willing to invest the time and effort to safety install these systems, then hire an expert.

    Changing a main breaker is NOT a DIY project. It is NOT just "a couple of screws".

    We are willing to help you. But we do not want you to get hurt or worse for your family.

    Thanks Dan, I completely understand.

    I'm trying to gain the knowledge by reading and asking question here on the forum. It has basically made me realize this will not be as easy as I thought. I'm definitely going to find a solar company. I'm going to try to find a place that will let me do the labor work and just pay them to interconnect. At this point I'm just asking a lot of questions so I can figure out what I need to purchase and do.

    Does anyone know of any solar installers in the Mesa area that would do the project cheaper and allow me to do the bulk of the physical labor?
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  • WhittakerJ
    WhittakerJ Solar Expert Posts: 67 ✭✭
    #69
    Re: Amateur doing a 10kw system, can someone tell me if I missed anything

    I just wanted to close out this thread by updating on my system, which just got finished installing last week. After all incentives my cost was approximately $13k which I'm hoping to recoup in about 5 years. The return on this investment should be about 17%. The total system size is 9.9kw. This put my cost at roughly $1.30 per watt completely installed.



    I also appreciate all the help and feedback that I received from this forum. If anyone would like to copy any piece of my system let me know and I can send you more detailed information.

    I hope my system insipires someone else to create a sustainable renewable source of energy!

    This was my originally drawing.


    Attachment not found.


    I hired an engineer to draw up these plans:

    Attachment not found.


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  • WhittakerJ
    WhittakerJ Solar Expert Posts: 67 ✭✭
    #70
    Re: Amateur doing a 10kw system, can someone tell me if I missed anything

    Here are some shots of the construction.

    7 ft holes to hold the structure up
    Attachment not found.

    Once complete I camouflaged it to hide it from neighbors' views
    camo_zps99e3af48.jpg

    5_zps771b5c86.jpg

    4_zps622dc1fc.jpg

    3_zpse872552c.jpg
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  • WhittakerJ
    WhittakerJ Solar Expert Posts: 67 ✭✭
    #71
    Re: Amateur doing a 10kw system, can someone tell me if I missed anything

    Once complete these are views from my drone.
    2_zps33bb34c2.jpg

    1_zps7deaa03d.jpg
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  • WhittakerJ
    WhittakerJ Solar Expert Posts: 67 ✭✭
    #72
    Re: Amateur doing a 10kw system, can someone tell me if I missed anything

    And last some pictures of the equipment. You can see I'm not green tagged or commissioned as of yet



    I now have an 800 sq ft shaded back yard!
    c_zps789a93ce.jpg



    Combiner/Fuse box and DC disconnect
    d_zps60a7c507.jpg



    Underside view
    e_zps9531a6e7.jpg


    Inverter and AC disconnect
    b_zps468145a5.jpg
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  • WhittakerJ
    WhittakerJ Solar Expert Posts: 67 ✭✭
    #73
    Re: Amateur doing a 10kw system, can someone tell me if I missed anything

    Meter socket and AC disconnect. As well surge protector on the right for whole house.
    a_zps407b177c.jpg

    Sorry for all the posts I could only do 5 pictures per!
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  • upa123
    upa123 Registered Users Posts: 17 ✭
    #74
    Re: Amateur doing a 10kw system, can someone tell me if I missed anything

    Well done sir, very nice installation. Cool drone pics , looks like you have some unfortunate shading from your eastern next door neighbor's tree.
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  • Blackcherry04
    Blackcherry04 Solar Expert Posts: 2,490 ✭✭✭
    #75
    Re: Amateur doing a 10kw system, can someone tell me if I missed anything

    I swear my neighbors trees have grown 20' higher since I installed my solar. I keep hoping for a storm that takes her trees out and leaves my panels alone. ..... lol Probably not likely to happen. It's a good reason to have Micro Inverters.
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #76
    Re: Amateur doing a 10kw system, can someone tell me if I missed anything
    Blackcherry04 wrote: »
    I swear my neighbors trees have grown 20' higher since I installed my solar. I keep hoping for a storm that takes her trees out and leaves my panels alone. ..... lol Probably not likely to happen. It's a good reason to have Micro Inverters.

    If your luck is like mine the storm would take her trees down, and drop them on your panels. :p
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  • Blackcherry04
    Blackcherry04 Solar Expert Posts: 2,490 ✭✭✭
    #77
    Re: Amateur doing a 10kw system, can someone tell me if I missed anything
    Cariboocoot wrote: »
    If your luck is like mine the storm would take her trees down, and drop them on your panels. :p
    Yeah, thats my luck too, she'd blame it on my panels. The trees are close to my fence, I took a ground saw on my side and cut down 6', hoping that I'd cut enough roots to slow them down, I think they grew more.
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  • WhittakerJ
    WhittakerJ Solar Expert Posts: 67 ✭✭
    #78
    Re: Amateur doing a 10kw system, can someone tell me if I missed anything
    Blackcherry04 wrote: »
    I swear my neighbors trees have grown 20' higher since I installed my solar. I keep hoping for a storm that takes her trees out and leaves my panels alone. ..... lol Probably not likely to happen. It's a good reason to have Micro Inverters.

    Yea I would have considered the micro inverters but the were not compatible with these 275w Trina's. And not to mention I paid like $3k for the inverter. micro inverters would have been twice that.
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  • WhittakerJ
    WhittakerJ Solar Expert Posts: 67 ✭✭
    #79
    Re: Amateur doing a 10kw system, can someone tell me if I missed anything
    upa123 wrote: »
    Well done sir, very nice installation. Cool drone pics , looks like you have some unfortunate shading from your eastern next door neighbor's tree.

    Yea unfortunately I live on a small lot and I believe winter solstice is the 21st which is a couple of weeks. So the sun is at it's furthest southern point. A lot of that shade is actually coming from my house. I'm eager to see how it affects the system. Hopefully by February I will have full sun.
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