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  1. #1
    Join Date
    Mar 2007
    Location
    Mesa AZ
    Posts
    1,181

    Default Service Panel De-Rated ?

    The panel was an original 200 amp Square D panel. 2003 home.
    Next to the main 175 amp breaker there was a black plastic plate glued to the cover stating the panel was de-rated Per NEC 690.64 (3) (2)
    Why would they de-rate the panel?

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  2. #2
    Join Date
    Mar 2007
    Location
    Ormond Beach, Florida
    Posts
    26,248

    Default Re: Service Panel De-Rated ?

    ARTICLE 690 Solar Photovoltaic Systems
    - 690.64 Point of Connection.
    - - (2) Bus or Conductor Rating. The sum of the ampere ratings of overcurrent devices in circuits supplying power to a busbar or conductor shall not exceed 120 percent of the rating of the busbar or conductor. In systems with panelboards connected in series, the rating of the first overcurrent device directly connected to the output of a utility-interactive inverter(s) shall be used in the calculations for all busbars and conductors.
    - - (3) Ground-Fault Protection. The interconnection point shall be on the line side of all ground-fault protection equipment.
    - - - Exception: Connection shall be permitted to be made to the load side of ground-fault protection, provided that there is ground-fault protection for equipment from all ground-fault current sources. Ground-fault protection devices used with supplies connected to the load-side terminals shall be identified and listed as suitable for backfeeding.

    Jerry Peck, Construction / Litigation Consultant
    Construction Litigation Consultants, LLC ( www.ConstructionLitigationConsultants.com )
    www.AskCodeMan.com

  3. #3
    Join Date
    Mar 2007
    Location
    Mesa AZ
    Posts
    1,181

    Default Re: Service Panel De-Rated ?

    Quote Originally Posted by Jerry Peck View Post
    ARTICLE 690 Solar Photovoltaic Systems
    - 690.64 Point of Connection.
    - - (2) Bus or Conductor Rating. The sum of the ampere ratings of overcurrent devices in circuits supplying power to a busbar or conductor shall not exceed 120 percent of the rating of the busbar or conductor. In systems with panelboards connected in series, the rating of the first overcurrent device directly connected to the output of a utility-interactive inverter(s) shall be used in the calculations for all busbars and conductors.
    - - (3) Ground-Fault Protection. The interconnection point shall be on the line side of all ground-fault protection equipment.
    - - - Exception: Connection shall be permitted to be made to the load side of ground-fault protection, provided that there is ground-fault protection for equipment from all ground-fault current sources. Ground-fault protection devices used with supplies connected to the load-side terminals shall be identified and listed as suitable for backfeeding.
    No solar or any evidence of prior solar.
    Close as I could figure an electric heat pump was added in 2012 to heat the pool

    Phoenix AZ Resale Home, Mobile Home, New Home Warranty Inspections. ASHI Certified Inspector #206929 Arizona Certified Inspector # 38440
    www.inspectaz.com

  4. #4
    Join Date
    Mar 2007
    Location
    Ormond Beach, Florida
    Posts
    26,248

    Default Re: Service Panel De-Rated ?

    Quote Originally Posted by Dan Harris View Post
    No solar or any evidence of prior solar.
    Close as I could figure an electric heat pump was added in 2012 to heat the pool
    Maybe they were planning on installing solar panels and then didn't?

    Otherwise there is no reason to apply that section.

    Jerry Peck, Construction / Litigation Consultant
    Construction Litigation Consultants, LLC ( www.ConstructionLitigationConsultants.com )
    www.AskCodeMan.com

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