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  1. #1
    Jeff Eastman's Avatar
    Jeff Eastman Guest

    Default Figuring out which way is up

    ......

    Last edited by Jeff Eastman; 12-20-2007 at 07:28 AM.
    Elite MGA Home Inspector E&O Insurance

  2. #2
    Richard Rushing's Avatar
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    Default Re: Figuring out which way is up

    Quote Originally Posted by Jeff Eastman View Post
    the setup:

    Is it possible to have 2 "service equipment panels"? Or would the 200amp panel be the service equipment and all other downstream panels?
    Two service panels.

    RR


  3. #3
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    Default Re: Figuring out which way is up

    Quote Originally Posted by Jeff Eastman View Post
    Is it possible to have 2 "service equipment panels"?
    Or 3, or 4, or 5, or 6.

    But not more than 6.

    (Remember, no more than 6 mains.)

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

  4. #4
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    Default Re: Figuring out which way is up

    Hi Jeff..First post here and I would agree with Richard that they are both mains with the one at the garage needing a seperation of ground and neutral as you noted,since it is a sub-panel or remote distribution panel.


  5. #5
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    Default Re: Figuring out which way is up

    I forgot to add ...

    How many circuits in the detached guest house?

    Most likely, that needs a 'main' at that structure for that structure, in addition to the main at the service equipment.

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

  6. #6
    Martin lehman's Avatar
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    Default Re: Figuring out which way is up

    Jerry, can you explain??
    From what I know (very minimal ) if there is more than one circuit at the separate building, there needs to be a separate grounding system. But even if that panel is fed by the service, it's required to have a main disconnect too??


  7. #7
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    Default Re: Figuring out which way is up

    From the NEC. (bold and underlining are mine)
    - ARTICLE 225 Outside Branch Circuits and Feeders
    - - 225.1 Scope.
    - - - This article covers requirements for outside branch circuits and feeders run on or between buildings, structures, or poles on the premises; and electric equipment and wiring for the supply of utilization equipment that is located on or attached to the outside of buildings, structures, or poles.

    - II. More Than One Building or Other Structure
    - - 225.31 Disconnecting Means.
    - - - Means shall be provided for disconnecting all ungrounded conductors that supply or pass through the building or structure.
    - - 225.32 Location.
    - - - The disconnecting means shall be installed either inside or outside of the building or structure served or where the conductors pass through the building or structure. The disconnecting means shall be at a readily accessible location nearest the point of entrance of the conductors. For the purposes of this section, the requirements in 230.6 shall be permitted to be utilized.
    - - - - Exception No. 1: For installations under single management, where documented safe switching procedures are established and maintained for disconnection, and where the installation is monitored by qualified individuals, the disconnecting means shall be permitted to be located elsewhere on the premises. (Jerry's note: This Exception 1 does not apply.)
    - - - - Exception No. 2: For buildings or other structures qualifying under the provisions of Article 685, the disconnecting means shall be permitted to be located elsewhere on the premises. (Jerry's note:
    "ARTICLE 685 Integrated Electrical Systems
    I. General
    685.1 Scope.
    This article covers integrated electrical systems, other than unit equipment, in which orderly shutdown is necessary to ensure safe operation. An integrated electrical system as used in this article is a unitized segment of an industrial wiring system where all of the following conditions are met: ". This Exception 2 does not apply.)

    Now on to the main section:
    - 250.32 Two or More Buildings or Structures Supplied from a Common Service.
    - - (D) Disconnecting Means Located in Separate Building or Structure on the Same Premises. Where one or more disconnecting means supply one or more additional buildings or structures under single management, and where these disconnecting means are located remote from those buildings or structures in accordance with the provisions of 225.32, Exception Nos. 1 and 2, all of the following conditions shall be met: (Jerry's note: Exceptions 1 and 2 do not apply - see above code. Thus, "The disconnecting means shall be installed either inside or outside of the building or structure served" . This also means the following items do not apply.)
    - - - (1) The connection of the grounded circuit conductor to the grounding electrode at a separate building or structure shall not be made.
    - - - (2) An equipment grounding conductor for grounding any non–current-carrying equipment, interior metal piping systems, and building or structural metal frames is run with the circuit conductors to a separate building or structure and bonded to existing grounding electrode(s) required in Part III of this article, or, where there are no existing electrodes, the grounding electrode(s) required in Part III of this article shall be installed where a separate building or structure is supplied by more than one branch circuit.
    - - - (3) Bonding the equipment grounding conductor to the grounding electrode at a separate building or structure shall be made in a junction box, panelboard, or similar enclosure located immediately inside or outside the separate building or structure.

    Which leaves us back where we started:
    - - 225.32 Location.
    - - - The disconnecting means shall be installed either inside or outside of the building or structure served or where the conductors pass through the building or structure. The disconnecting means shall be at a readily accessible location nearest the point of entrance of the conductors. For the purposes of this section, the requirements in 230.6 shall be permitted to be utilized.

    I.e., the service equipment disconnects are located at the service equipment (on the main house), and there were two disconnects. The disconnect for the separate structure feeds a feeder which goes to the separate structure, and those feeder conductors need a disconnect located on or in the separate structure ("the building or structure served").

    Then we have the familiar:
    - 225.33 Maximum Number of Disconnects.
    - - (A) General. The disconnecting means for each supply permitted by 225.30 shall consist of not more than six switches or six circuit breakers mounted in a single enclosure, in a group of separate enclosures, or in or on a switchboard. There shall be no more than six disconnects per supply grouped in any one location.

    Were there more than 6 disconnects in/on the separate structure? If not, not a problem. If yes, then a separate main is needed (and this 'main' is not the "main" in the normal sense of what one thinks, i.e., it is not "service equipment", it is just a secondary 'main' to turn off power to the separate structure should the need arrive, with the neutrals and grounds isolated).

    Jerry Peck, Construction / Litigation Consultant
    Construction Litigation Consultants, LLC ( www.ConstructionLitigationConsultants.com )
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    Default Re: Figuring out which way is up

    Quote Originally Posted by Jeff Eastman View Post
    The guest house have the equipment grounds on same bus bar with bus bar bonded to panel (defect, I know).
    I'll ask it differently than Fritz.

    *I* 'read' it as 'The guest house have the equipment grounds on same bus bar as the neutrals are, with bus bar bonded to panel (defect, I know)'.

    Although that is not what was stated.

    If meant as *I* 'read' it, then, yes, it is a defect.

    If meant as 'something else', then please explain. May, or may not, be a defect.

    Jerry Peck, Construction / Litigation Consultant
    Construction Litigation Consultants, LLC ( www.ConstructionLitigationConsultants.com )
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  9. #9
    Martin lehman's Avatar
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    Default Re: Figuring out which way is up

    I belive you can't combine the neutal and ground because the panel is being fed by the service. If it were to be a service panel, it would not be fed by another.

    Last edited by Martin lehman; 07-14-2007 at 09:00 AM. Reason: sounds better

  10. #10
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    Default Re: Figuring out which way is up

    Quote Originally Posted by Fritz Kelly View Post
    Isn't it true that if the guest house panel is not bonded by a ground or conduit to the house panel, and the guest house panel has its own ground rod, the guest house panel becomes its own service panel and combining neutrals and grounds on the same bus, bonded to the panel body is OK?
    True, with conditions. See 250.32(B)(2) - (1), (2), and (3), however, I doubt that a Guest House would comply with those requirements, thus, the neutral would *most likely* NOT be bonded to ground.

    Here is the NEC section. (bold and underlining are mine)
    - 250.32 Two or More Buildings or Structures Supplied from a Common Service.
    - - (A) Grounding Electrode. Where two or more buildings or structures are supplied from a common ac service by a feeder(s) or branch circuit(s), the grounding electrode(s) required in Part III of this article at each building or structure shall be connected in the manner specified in 250.32(B) or (C). Where there are no existing grounding electrodes, the grounding electrode(s) required in Part III of this article shall be installed.
    - - - Exception: A grounding electrode at separate buildings or structures shall not be required where only one branch circuit supplies the building or structure and the branch circuit includes an equipment grounding conductor for grounding the conductive non–current-carrying parts of all equipment. (Jerry's note: Notice that this exception ONLY applies where there is *ONE* branch circuit. Thus, for a Guest House, it would most likely not apply.)
    - - (B) Grounded Systems. For a grounded system at the separate building or structure, the connection to the grounding electrode and grounding or bonding of equipment, structures, or frames required to be grounded or bonded shall comply with either 250.32(B)(1) or (2).
    - - - (1) Equipment Grounding Conductor. An equipment grounding conductor as described in 250.118 shall be run with the supply conductors and connected to the building or structure disconnecting means and to the grounding electrode(s). The equipment grounding conductor shall be used for grounding or bonding of equipment, structures, or frames required to be grounded or bonded. The equipment grounding conductor shall be sized in accordance with 250.122. Any installed grounded conductor shall not be connected to the equipment grounding conductor or to the grounding electrode(s).
    - - - (2) Grounded Conductor. Where (1) an equipment grounding conductor is not run with the supply to the building or structure, (2) there are no continuous metallic paths bonded to the grounding system in both buildings or structures involved, and (3) ground-fault protection of equipment has not been installed on the common ac service, the grounded circuit conductor run with the supply to the building or structure shall be connected to the building or structure disconnecting means and to the grounding electrode(s) and shall be used for grounding or bonding of equipment, structures, or frames required to be grounded or bonded. The size of the grounded conductor shall not be smaller than the larger of
    - - - - (1) That required by 220.22
    - - - - (2) That required by 250.122
    - - (C) Ungrounded Systems. The grounding electrode(s) shall be connected to the building or structure disconnecting means.

    Note that the above states "Where there are no existing grounding electrodes, the grounding electrode(s) required in Part III of this article shall be installed"
    - III. Grounding Electrode System and Grounding Electrode Conductor
    250.50 Grounding Electrode System.
    - - If available on the premises at each building or structure served, each item in 250.52(A)(1) through (A)(6) shall be bonded together to form the grounding electrode system. Where none of these electrodes are available, one or more of the electrodes specified in 250.52(A)(4) through (A)(7) shall be installed and used.
    - - 250.52 Grounding Electrodes.
    - - - (A) Electrodes Permitted for Grounding.
    (then it goes on into ground rods, pipes, etc.)

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

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