Building Code and Building Construction - Questions and Answers
Or when you want to know how construction is supposed to be done.

|
AskCodeMan.com
|
The following Codemen are available to answer your questions:
All Codes and Standards - Jerry Peck, Codeman


Q&A Board links
  • REGISTER

  • FAQ

  • LOGIN

  • Q&A BOARD INDEX

  • View New Questions

  • View Unanswered Questions

  • View Active Questions/Answers

  • Mark Questions as read

  • View Your Questions

  • Go To Your User Control Panel




  • Links to:
  • Construction Litigation Consultants


  • Florida Building Commission

  • Florida Building Codes Online


  • International Code Council

  • ICC Codes Free Online


  • Building Officials and Administrators of Florida




  • Product Approvals
  • Florida Product Approval

  • ICC Evaluation Reports Search

  • Miami-Dade NOA Search




  • Inspector and Contractor License Search
  • Search Florida Licenses




  • Technical links
  • Technical Information page


























































  • Contact Codeman



  • Custom Search

    Working Space and exterior enclosures

    Working Space and exterior enclosures

    New postby Mark W. on Thu Oct 22, 2009 9:27 am

    Hi, I am an EOSH coordinator that has been asked to review plans for the installation of some communication equipment in an exterior metal enclosure. The enclosure will be a stainless steel NEMA 3R box, 72”H x 48”W x 24”D. Power will enter the box from the side into a service entrance panelboard mounted to equipment channels on the back wall of the NEMA box. The panelboard that will in turn feed the equipment and a GFCI outlet mounted next to the panelboard. The question has been raised that this set up violates the NEC / OSHA working space requirements around the panelboard.

    My evaluation of the situation is that those requirements are not applicable since the NEC/OSHA provisions for working space do not apply to the communications equipment and that with the cover on the panelboard there will be no exposed live parts.

    If it becomes necessary to remove the cover to the panelboard, then it will be necessary to disconnect the power feed to the enclosure prior to the work so that there will be no live parts inside the enclosure.

    Alternatively, I’m not even sure that the working space requirements apply to the front opening of the panelboard, since that is a subsystem inside a larger enclosure and that the rules would actually apply to the larger enclosure itself.

    Any comments?
    Mark W.
     
    Posts: 2
    Joined: Thu Oct 22, 2009 9:23 am

    Re: Working Space and exterior enclosures

    New postby Mark W. on Thu Oct 22, 2009 12:09 pm

    Follow up.

    I just spoke to the local OSHA office and they have told me that the working space befgins at the face of the outer box, not at the face of the internal panelboard.

    So, I guess that answers that question.
    Mark W.
     
    Posts: 2
    Joined: Thu Oct 22, 2009 9:23 am

    Re: Working Space and exterior enclosures

    New postby Jerry Peck - Codeman on Thu Oct 22, 2009 1:26 pm

    Hi Mark,

    Mark W. wrote:The question has been raised that this set up violates the NEC / OSHA working space requirements around the panelboard.

    My evaluation of the situation is that those requirements are not applicable since the NEC/OSHA provisions for working space do not apply to the communications equipment and that with the cover on the panelboard there will be no exposed live parts.


    I see several things wrong with what you are proposing.

    First there is the location and accessibility of the overcurrent devices in that panelboard which is enclosed in that screwed on cover (I am presuming the cover is screwed on due to its size, if the cover is a hinged cover which is freely opened, the following would not apply):
    - From the 2008 NEC. (underlining and bold are mine)
    - - ARTICLE 240 Overcurrent Protection
    - - - II. Location.
    - - - - 240.24 Location in or on Premises.
    - - - - - (A) Accessibility. Overcurrent devices shall be readily accessible and shall be installed so that the center of the grip of the operating handle of the switch or circuit breaker, when in its highest position, is not more than 2.0 m (6 ft 7 in.) above the floor or working platform, unless one of the following applies:
    - - - - - - (1) For busways, as provided in 368.17(C).
    - - - - - - (2) For supplementary overcurrent protection, as described in 240.10.
    - - - - - - (3) For overcurrent devices, as described in 225.40 and 230.92.
    - - - - - - (4) For overcurrent devices adjacent to utilization equipment that they supply, access shall be permitted to be by portable means.
    - - - - - (B) Occupancy. Each occupant shall have ready access to all overcurrent devices protecting the conductors supplying that occupancy, unless otherwise permitted in 240.24(B)(1) and (B)(2).
    - - - - - - (1) Service and Feeder Overcurrent Devices. Where electric service and electrical maintenance are provided by the building management and where these are under continuous building management supervision, the service overcurrent devices and feeder overcurrent devices supplying more than one occupancy shall be permitted to be accessible only to authorized management personnel in the following:
    - - - - - - - (1) Multiple-occupancy buildings
    - - - - - - - (2) Guest rooms or guest suites
    - - - - - - (2) Branch-Circuit Overcurrent Devices. Where electric service and electrical maintenance are provided by the building management and where these are under continuous building management supervision, the branch-circuit overcurrent devices supplying any guest rooms or guest suites without permanent provisions for cooking shall be permitted to be accessible only to authorized management personnel.

    Keep in mind that 240.24(A) references the overcurrent devices as being "readily accessible".
    - - Accessible, Readily (Readily Accessible). Capable of being reached quickly for operation, renewal, or inspections without requiring those to whom ready access is requisite to climb over or remove obstacles or to resort to portable ladders, and so forth.

    Keep in mind that 240.24(B)(2) references the overcurrent devices "shall have ready access", i.e., are "accessible" unless "under continuous building management supervision".
    - Accessible (as applied to equipment). Admitting close approach; not guarded by locked doors, elevation, or other effective means.

    If it becomes necessary to remove the cover to the panelboard, then it will be necessary to disconnect the power feed to the enclosure prior to the work so that there will be no live parts inside the enclosure.


    This "then it will be necessary to disconnect the power feed to the enclosure" indicates that someone will need to do the above action, that the above action will not be automatically done upon removal or opening of the main NEMA enclosure cover, which then allows for the panelboard to be left energized unless someone takes that other action.

    This means that the panelboard and all other electrical equipment in that main NEMA enclosure "could be", may even "likely be", subject to "examination, adjustment, servicing, or maintenance while energized".
    - 110.26 Spaces About Electrical Equipment.
    - - Sufficient access and working space shall be provided and maintained about all electrical equipment to permit ready and safe operation and maintenance of such equipment.
    - - - (A) Working Space. Working space for equipment operating at 600 volts, nominal, or less to ground and likely to require examination, adjustment, servicing, or maintenance while energized shall comply with the dimensions of 110.26(A)(1), (A)(2), and (A)(3) or as required or permitted elsewhere in this Code.

    Installing an automatic shut off switch to disconnect all power to that enclosure upon removal or opening of the cover would not necessarily solve all problems as that would raise other questions and concerns, such as is that enclosure, its cover, and the interlocking switch suitable for that purpose, i.e., has it been tested, listed, and labeled as a unit for that purpose? The answer would be no, it has not been tested, listed, and labeled for that purpose, which would mean a field evaluation and listing would need to be done.

    Alternatively, I’m not even sure that the working space requirements apply to the front opening of the panelboard, since that is a subsystem inside a larger enclosure and that the rules would actually apply to the larger enclosure itself.


    That would apply if the entire enclosure and all associated equipment in it were assembled by a manufacturer who had the entire assembly tested, listed, and labeled to some established standard. If that were done, I doubt that panel would be allowed to be set back in that enclosure as you are describing, in part due to the required working spaces while energized (unless there was the automatic shut down switch I described above incorporated as part of the listed equipment assembly).

    One concern relating to working space, presuming the panelboard is still energized, is that the bottom of the enclosure would not have the required 3 feet in front of the panelboard to the upturned lip of the enclosure to which the cover either closes over or is attached to. The depth of the enclosure would likely need to be 42 inches or greater to provide the minimum required working space of 3 feet in front of the panelboard.

    I have other concerns on the installation as I am envisioning your description of it.

    There is not enough information to make other comments, and some of what I am envisioning may be incorrect, please provide additional information and correction of what I am describing where different than what you were describing.
    Jerry Peck - CodeMan
    AskCodeMan.com

    Construction and Litigation Consultant
    Construction Litigation Consultants, LLC.
    ConstructionLitigationConsultants.com
    User avatar
    Jerry Peck - Codeman
    Site Admin
     
    Posts: 1124
    Joined: Fri Dec 12, 2008 12:06 pm


    Return to Electrical: Service Equipment, electrical panels, wiring, lighting, switches, receptacles, etc.



    Who is online

    Users browsing this forum: No registered users and 1 guest



    www.AskCodeMan.com
    cron