Sunny Boy Wiring

adam1984
adam1984 Solar Expert Posts: 72 ✭✭✭✭
in PV Installers Forum - NEC, Wiring, Installation #1
So i just wired in a 4k solar system into an SMA sunny boy 4000 and have it up and running. All the DC wiring is complete. Right now i have L1, L2, N, and PE coming out . The only issue is i just got a bidirectional meter installed. I am wondering if anyone has experience with these. Do i tie this into the main AC panel or does this go directly into the bidirectional meter? Also, is there a way to determine if the utility is Wye or Delta, and if it is 208V or 240V? Any help is appreciated. I am trying to get this up and running to show the wife that we can spin the meter backwards. Everything is great so far, and SB4000's have auto grid sensor, so it will automatically set itself to 208 or 240. I just need advice on how to get this tied in to the utility. THANKS!
Adam
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,637 admin
    #2
    Re: Sunny Boy Wiring

    I will take a stab at a couple of your questions.
    adam1984 wrote: »
    So i just wired in a 4k solar system into an SMA sunny boy 4000 and have it up and running. All the DC wiring is complete. Right now i have L1, L2, N, and PE coming out . The only issue is i just got a bidirectional meter installed. I am wondering if anyone has experience with these. Do i tie this into the main AC panel or does this go directly into the bidirectional meter?
    The utility replaced your exiting meter with a new bi-directional meter for net metering?

    If so, then the SunnyBoy AC would connect a pair of 240 VAC circuit breakers at the bottom of the bus bar (farthest away from Main Panel Breaker/fuse block/AC input).

    Have you reviewed the NEC/Building code requirements on how to properly size your breakers/solar GT system for your existing AC main panel?

    Does your local authority/utility require an accessible lockable AC knife switch/breaker panel so they can pad lock off the GT AC Inverter Output? (many inverters have the lockout as part of their wiring panel)
    Also, is there a way to determine if the utility is Wye or Delta, and if it is 208V or 240V?
    Generally, Split Phase house wiring in North America is 120/240 VAC with a common neutral.

    In California, typically small business is "Y" Wye connected 3 phase 120/208 VAC (center of the Y to any power leg is 120 VAC, Across any power leg is 208 VAC).

    If you have Delta, you will not have a common neutral... Because you have three independent transformers, the split phase 120/240 VAC is only common to one transformer, and I believe the neutral with that transformer is also known as a "Stinger".

    You probably should have a licensed electrician help you with the AC connections (and may be required by your inspectors/utility anyway).
    Any help is appreciated. I am trying to get this up and running to show the wife that we can spin the meter backwards. Everything is great so far, and SB4000's have auto grid sensor, so it will automatically set itself to 208 or 240.
    As far as I know, the GT inverters either need to be ordered by part number for 208 or 240 VAC, and/or need to be reprogrammed on site for the appropriate single/three phase setup (may be factory approved programming required to set the 208/240 vac nominal voltage using their tools/passwords or through their retailer/installer--usually a customer is not allowed to adjust safety related parameters for UL/NRTL Listed devices).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • ggunn
    ggunn Solar Expert Posts: 1,973 ✭✭✭
    #3
    Re: Sunny Boy Wiring
    adam1984 wrote: »
    So i just wired in a 4k solar system into an SMA sunny boy 4000 and have it up and running. All the DC wiring is complete. Right now i have L1, L2, N, and PE coming out . The only issue is i just got a bidirectional meter installed. I am wondering if anyone has experience with these. Do i tie this into the main AC panel or does this go directly into the bidirectional meter? Also, is there a way to determine if the utility is Wye or Delta, and if it is 208V or 240V? Any help is appreciated. I am trying to get this up and running to show the wife that we can spin the meter backwards. Everything is great so far, and SB4000's have auto grid sensor, so it will automatically set itself to 208 or 240. I just need advice on how to get this tied in to the utility. THANKS!
    Adam
    No offense intended, but it sounds to me like you should enlist the services of an electrician.
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  • jagec
    jagec Solar Expert Posts: 157 ✭✭
    #4
    Re: Sunny Boy Wiring
    BB. wrote: »

    As far as I know, the GT inverters either need to be ordered by part number for 208 or 240 VAC, and/or need to be reprogrammed on site for the appropriate single/three phase setup (may be factory approved programming required to set the 208/240 vac nominal voltage using their tools/passwords or through their retailer/installer--usually a customer is not allowed to adjust safety related parameters for UL/NRTL Listed devices).

    -Bill

    The SB4000US will auto-sense 240 or 208 VAC, but has internal jumpers that must be changed for 208 Delta and the non-"Stinger" legs of 240 Delta. The default jumper configuration is correct for a normal split-phase or Wye installation.

    But yeah, the OP needs to call an electrician before he starts playing around with the grid.
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  • adam1984
    adam1984 Solar Expert Posts: 72 ✭✭✭✭
    #5
    Re: Sunny Boy Wiring

    Gotcha.
    BB- Yes the utility company has already switched over to a bidirectional meter. It is wired up and operating.
    Ill see what i can do as far as getting an electrician to assist, or just do the whole thing.
    I just was wondering where exactly the inverter was tying into the home.
    No offense taken. Probably better to go with an electrician.
    Thanks,
    Adam
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  • Peak Solar
    Peak Solar Registered Users Posts: 13 ✭
    #6
    Re: Sunny Boy Wiring
    adam1984 wrote: »
    Gotcha.
    BB- Yes the utility company has already switched over to a bidirectional meter. It is wired up and operating.
    Ill see what i can do as far as getting an electrician to assist, or just do the whole thing.
    I just was wondering where exactly the inverter was tying into the home.
    No offense taken. Probably better to go with an electrician.
    Thanks,
    Adam


    Backfed into the main service panel.
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,637 admin
    #7
    Re: Sunny Boy Wiring

    Sorry, I missed your question...

    Yes, as Peak Solar answered, it is just another branch circuit into your main breaker panel.

    There are some rules however... The breaker cannot be larger than 20% of the main panel's design... I.e., if you have a 200 amp panel, then you can install a 40 amp breaker (typically two pole 240 VAC branch circuit).

    If you have a 200 amp main service with a 125 amp main breaker, then the maximum solar GT breaker would be 40 amps + 75 amps = 115 amps (i.e., 200 amp rating - 125 amp service breaker = 75 amps "extra").

    Also, the GT breakers need to be installed at the "bottom" of the box away from the main input breaker... This ensures that the bus bars in the service panels never carry more than 100% of rated current. If you place the GT breakers at the "top" next to the main breaker, then there would be sections of the bus bars that would (could) be carrying 120% of design worth of current.

    When you get into the details--it can get pretty confusing. And, at times, the local building inspectors will add their own rules.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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