3 single phase Sunny Boys to 3phase 120/240 Volts.

Batikikik
Batikikik Solar Expert Posts: 141 ✭✭✭✭✭
in General Solar Power Topics #1
I have a project 27kW photovoltaic system, which has 3 sunny boys 8000US . Distribution is 3phase 240V. Attached pics. Who can give me an ideo or send any diagram for bets way to connect those 3 single phase inverters to 3 phase distribution . thank you
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #2
    Re: 3 single phase Sunny Boys to 3phase 120/240 Volts.

    Are you sure it is 240 vac and not 208 vac?

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • Solar Guppy
    Solar Guppy Solar Expert Posts: 1,989 ✭✭✭
    #3
    Re: 3 single phase Sunny Boys to 3phase 120/240 Volts.

    That's 208 3-Phase

    You have posted you have a master electrician on staff, that's his job, not ours or yours since you lack the proper qualification to be messing with commercial power distribution
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  • ggunn
    ggunn Solar Expert Posts: 1,973 ✭✭✭
    #4
    Re: 3 single phase Sunny Boys to 3phase 120/240 Volts.
    Batikikik wrote: »
    I have a project 27kW photovoltaic system, which has 3 sunny boys 8000US . Distribution is 3phase 240V. Attached pics. Who can give me an ideo or send any diagram for bets way to connect those 3 single phase inverters to 3 phase distribution . thank you
    See pages 23-25 of the manual.
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  • Batikikik
    Batikikik Solar Expert Posts: 141 ✭✭✭✭✭
    #5
    Re: 3 single phase Sunny Boys to 3phase 120/240 Volts.

    Solar Guppy you always posting negative posts. I am not whos gonna do the job. I am bringing this on table to learn and thats why there is a forum.
    Service is not 208 it is 240. And like you see in a picture there is also single phase portion on main. So maybe will be beteer and cost effective to connect to sing phase ???
    combine all 3 40A breakers to one 120A and connect to single phase.
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  • jeffkruse
    jeffkruse Solar Expert Posts: 205 ✭✭✭
    #6
    Re: 3 single phase Sunny Boys to 3phase 120/240 Volts.
    Solar Guppy wrote: »
    That's 208 3-Phase

    You have posted you have a master electrician on staff, that's his job, not ours or yours since you lack the proper qualification to be messing with commercial power distribution

    +1

    I agree with you.
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  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    #7
    Re: 3 single phase Sunny Boys to 3phase 120/240 Volts.

    if you are contemplating combining the different phases into one then you are headed for trouble.
    listen. do you hear it?
    it's the sound of the fire trucks approaching.:cry:
    it is clear that you don't understand the meaning of different phases and you can learn, but not the hard way please. maybe your electrician can explain it to you seeing as how you pay him anyway for it is difficult for us to put into words that you can understand.
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #8
    Re: 3 single phase Sunny Boys to 3phase 120/240 Volts.

    The problem is that there is no "simple" 3 phase 120/240 VAC power...

    There is 120/208 Wye connected ("Y" connected transformers with the center of the Y being neutral).

    And there is 240 VAC Delta with one transformer that has a center tap for 120/240 VAC split phase power.
    Wye has three legs with 208 V between any two legs. There is 120 V from any of the legs to Neutral.

    Delta has three legs with 230 V between any two legs. There is 115 V between Ground and 2 of the hot legs. The voltage between Ground and the other hot is ~160 V (this is not used).
    Here are some pictures of various transformer configurations:

    http://www.federalpacific.com/university/transbasics/chapter3.html

    And here is a 240 VAC Delta with a single center tap neutral for 120/240:

    attachment.php?attachmentid=1987&d=1311446124

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • Batikikik
    Batikikik Solar Expert Posts: 141 ✭✭✭✭✭
    #9
    Re: 3 single phase Sunny Boys to 3phase 120/240 Volts.

    Ok. Main panel is 400 amp 3phase 4 wire 240volts. (Attached photo)
    Solar inverters are 3 sb8000US 1phase 40A each.
    What will be best way for interconnection ?
    a) Combine 3 inverters in sub panel and have 100a 3pole circuit breaker on panel ?
    b) Connect on tap which is marked on picture.
    c) Connect each inverter with individual 40a breaker per each phase?

    Busbar rating is 400a and main breaker size is 400a.
    Solar breaker size will be 100A.

    This match 120% rule because 400a is each leg.



    Thank you very much!
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #10
    Re: 3 single phase Sunny Boys to 3phase 120/240 Volts.

    I am no 3 phase expert--but that sure looks to be wired as a 208/120 VAC grounded Wye system from the color coding (although, there is no required US standard for 3 phase coding).

    The reason I ask is because the Sunny Boy 8000us is only rated for 240/277 volts and not for 208 vac.

    Also, what version of NEC does your AHJ use? Does not the older NEC force commercial installations to use 100% rated bus bar current and limit 120% to residential use only?

    -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 ✭✭✭
    #11
    Re: 3 single phase Sunny Boys to 3phase 120/240 Volts.
    BB. wrote: »
    I am no 3 phase expert--but that sure looks to be wired as a 208/120 VAC grounded Wye system from the color coding (although, there is no required US standard for 3 phase coding).

    The reason I ask is because the Sunny Boy 8000us is only rated for 240/277 volts and not for 208 vac.

    Also, what version of NEC does your AHJ use? Does not the older NEC force commercial installations to use 100% rated bus bar current and limit 120% to residential use only?

    -Bill
    If you look at p.23 of the SB5000/6000/7000 manual (http://files.sma.de/dl/4752/SB50US-80US-eng-IUS112633.pdf), you will see that the SB is compatible with 208, 240, and 277 VAC. You cannot connect to 480 delta (no neutral), but the rest are OK.
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #12
    Re: 3 single phase Sunny Boys to 3phase 120/240 Volts.

    But the plan is for the SB8000us model... and from the same page:
    * The Sunny Boy 8000-US must not be connected to a 208 V grid.

    Which is what, typically, is found in California--208 VAC grounded Wye for office park power. That is why it is critical that the service be correctly identified.

    And yes, it is still possible to connect to one phase of 480 VAC delta circuit--if it has a "Stinger" (center tapped phase). However, I would wonder if the Utility would allow a bunch of power to only be dumped on one phase instead of across all three (change to "Wye" 480 VAC and use 277 VAC to neutral connections--very common out here for lighting circuits in buildings).

    In any case, this is not a 480 volt service.

    -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 ✭✭✭
    #13
    Re: 3 single phase Sunny Boys to 3phase 120/240 Volts.
    BB. wrote: »
    But the plan is for the SB8000us model... and from the same page:"* The Sunny Boy 8000-US must not be connected to a 208 V grid. "
    That was confusing to me until I realized that I have a different (older) version of the manual from the one I linked you to, and it only has the SB5000/6000/7000 inverters. I did not catch that it is the 8000 they are using. I will download the new manual post haste; thanks for pointing that out to me.

    Now what is confusing me is why the 8000 would be different from the rest of their line. Do you know? If not, I'll call SMA and ask them.
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  • Batikikik
    Batikikik Solar Expert Posts: 141 ✭✭✭✭✭
    #14
    Re: 3 single phase Sunny Boys to 3phase 120/240 Volts.

    SMA has 240V 277V and 208V(transformerless) options.

    So what `s the best way to connect ?
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  • ggunn
    ggunn Solar Expert Posts: 1,973 ✭✭✭
    #15
    Re: 3 single phase Sunny Boys to 3phase 120/240 Volts.
    BB. wrote: »
    But the plan is for the SB8000us model... and from the same page:


    Which is what, typically, is found in California--208 VAC grounded Wye for office park power. That is why it is critical that the service be correctly identified.

    And yes, it is still possible to connect to one phase of 480 VAC delta circuit--if it has a "Stinger" (center tapped phase). However, I would wonder if the Utility would allow a bunch of power to only be dumped on one phase instead of across all three (change to "Wye" 480 VAC and use 277 VAC to neutral connections--very common out here for lighting circuits in buildings).

    In any case, this is not a 480 volt service.

    -Bill
    I am not a three phase expert, either (I am working on it), but I haven't yet seen a 480 with a stinger, only a 240 configured that way, with 120 to ground on two lines and 208 to ground on the third. I've seen corner grounded 480 and 480 delta/277 wye with a grounded center, but none like you mention. Google doesn't find it, either. Can you point me to some documentation?
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #16
    Re: 3 single phase Sunny Boys to 3phase 120/240 Volts.

    Ggunn,

    You know way more than I about 3 phase and what may be available from a utility drop.

    I was trying to make the point that a large solar system would need to drop its power across the three phases equally.

    Batikikik,

    Do you know if your AHJ will accept 120% on bus bars for commercial installation?

    What is the rating of the bus system/enclosure we see here?

    What is the total breakers on each phase, including those wired of the bottom of the main breaker (could get into questions about bus rating of the beaker connection and the jumper wires to the two pole breakers off to the bottom of the box.

    Does this even look like it is to code as is? Those "jumpers" seem a bit out in left field vs what would be allowed by code unless this was some sort of engineered solution.

    -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 ✭✭✭
    #17
    Re: 3 single phase Sunny Boys to 3phase 120/240 Volts.
    BB. wrote: »
    Ggunn,

    You know way more than I about 3 phase and what may be available from a utility drop.

    I was trying to make the point that a large solar system would need to drop its power across the three phases equally.

    I wouldn't bet on that, but I am certainly on a learning curve. ;^)

    One can connect three 240V SB's phase to phase to a 240 delta, one across each side of the triangle. You must configure them to not use a neutral.
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #18
    Re: 3 single phase Sunny Boys to 3phase 120/240 Volts.

    ggunn,

    You are correct... But not knowing what is coming into the building (if it is 240 3 phase--then it would be Delta, but then it would have no 120 VAC service without further transformers [or a "stinger" center tap on one of the delta transformers]--which this installation is supposed to have), the requirements of the local utility, or what code the local AHJ is using--makes any suggestions here more or less useless.

    From the little I know, 240 3 phase would not be standard for northern California for an office park type setup. 208/120 Wye or 480/277 Wye would be what I would expect (again, from my very tiny experience).

    This forum is not setup for provide detailed engineering analysis of high(er) power setups. And no Power Engineer could "wet stamp" a post here (especially without details of that installation).

    Best we can offer is some general observations and suggest that a local Electrician/Power Engineer evaluate and submit the plans to the local AHJ and Utility (which they probably require anyway).

    -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 ✭✭✭
    #19
    Re: 3 single phase Sunny Boys to 3phase 120/240 Volts.
    BB. wrote: »
    ggunn,

    You are correct... But not knowing what is coming into the building (if it is 240 3 phase--then it would be Delta, but then it would have no 120 VAC service without further transformers--which this installation is supposed to have), the requirements of the local utility, or what code the local AHJ is using--makes any suggestions here more or less useless.

    Agreed that this is useless conjecture, but to come full circle, a 240 delta with a stinger would provide 120 service and one could still connect three SB's around it for a balanced connection. It's one of the examples in the installation manual.
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  • Batikikik
    Batikikik Solar Expert Posts: 141 ✭✭✭✭✭
    #20
    Re: 3 single phase Sunny Boys to 3phase 120/240 Volts.

    Here is main panel
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #21
    Re: 3 single phase Sunny Boys to 3phase 120/240 Volts.

    I am going to close this thread... At these energy levels, and from looking at the previous photographs--this is something beyond the ability of our forum to give safe and useful information.

    So, I am going to close this thread.

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