Higher amp breaker or new 200amp main panel required?

kailm
kailm Registered Users Posts: 5 ✭✭
in PV Installers Forum - NEC, Wiring, Installation #1
Hi All,

I have been doing lot of reading, but with certain % and max being thrown around, I want to ask the question that applies to my situation.

I have solar on the roof with 230w panels with 190w enphase inverters x 8.   
8x190 = 1520w 6.33A (240v, note using inverter max rating since it cannot produce beyond 190w)
This feeds to a 10guage wire from roof to 60amp PV disconnect breaker, then it feeds from there to 15A breaker on the main breaker panel.
Service to home is 100A breaker (to home load panel).   The main panel rating is 125A.

I plan to add 12 x 290w panels with enphase 250w inverters.
12x250w = 3000w = 12.5A (240v)

Question is do I just up to a 20A breaker into the main panel, or would I need a main panel upgrade to 200A (bus bar rating)?
This would put me at 18.83A @ 240v.  This would seem like a 20A breaker into the main panel would work.

Thanks
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  • dennis461
    dennis461 Registered Users Posts: 109 ✭✭✭
    #2
      (Busbar Rating (A) x 1.2) - Main Breaker Rating (A) = Max PV (A)
    (125A x 1.2) -100A = 50A.

    Should be OK, raising the PV breaker size.
    What size wire did you plan on (or have already installed) from existing 15A breaker.
    Camden County, NJ, USA
    19 SW285 panels
    SE5000 inverter
    grid tied
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  • kailm
    kailm Registered Users Posts: 5 ✭✭
    edited April 2017 #3
    Thank you for explaining that formula!
    I will be using 10gauge wire.  I will up the breaker to 30A for future then!



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  • jonr
    jonr Solar Expert Posts: 1,386 ✭✭✭✭
    edited April 2017 #4
    My understanding is that use of the formula requires the GT breaker to be at the bottom of the panel.  But you would be OK anywhere.

    I am available for custom hardware/firmware development

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  • dennis461
    dennis461 Registered Users Posts: 109 ✭✭✭
    #5
    jonr said:
    My understanding is that use of the formula requires the GT breaker to be at the bottom of the panel.  But you would be OK anywhere.
    The formula does not necessarily force the location of the PV (GT) breaker.  The code section does this.  Interestingly, when my installation was completed, the electrician made note of the location, bottom of panel vs top of panel near the main breaker.  The code was re-written for 2017 as apparently many western states have center fed panels.

    http://solarprofessional.com/articles/design-installation/nec-2017-updates-for-pv-systems/page/0/3
    Camden County, NJ, USA
    19 SW285 panels
    SE5000 inverter
    grid tied
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  • kailm
    kailm Registered Users Posts: 5 ✭✭
    #6
    Here it is my addon panels done!
    https://enlighten.enphaseenergy.com/pv/public_systems/tqvv13675/overview

    Added 6x2 bottom rows to my array.

    Thanks for your help @dennis461 @jonr




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