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

    Using meter can as a pas thru to load center

    Using meter can as a pas thru to load center

    New postby bigdog on Mon Feb 03, 2014 8:21 pm

    Hi Jerry, I saw a feed to a well pump for irrigation wired thru a meter can to the loadcenter on the adjacent wall in the garage today. As this is not typical it seems like it may not be proper.

    Can the AHJ ok something like this? The owner stated a permit was pulled but all I can find is the original irrigation subs permit with no specific info available online at PBC building department. As well permits are hard to get when you already have city water, the breaker looked slightly different from the others meaning I don't think it was installed with the others and it was not identified. Doesn't feel right.

    What say you.
    David
    bigdog
     
    Posts: 47
    Joined: Thu Apr 12, 2012 10:54 pm

    Re: Using meter can as a pas thru to load center

    New postby Jerry Peck - Codeman on Mon Feb 03, 2014 9:45 pm

    bigdog wrote:Hi Jerry, I saw a feed to a well pump for irrigation wired thru a meter can to the loadcenter on the adjacent wall in the garage today. As this is not typical it seems like it may not be proper.

    Can the AHJ ok something like this?


    David,

    Can the AHJ approved something like that? Sure, they - can - approved something like that but it is not allowed by the code so I doubt that they actually did approve that, at least not knowingly (contractor may have hidden the conduits/cables so the inspector would not see them entering or leaving the meter can).

    The only conductors allowed in the meter can (with possibly a very few exceptions, none of which I can think of) with the service entrance conductors are the service entrance conductors.

    One can installed the service entrance conductors from the service laterals/overhead service drops through a CT can then continue to the main disconnect service equipment panel, where the conductors from the CT's run into the meter can, but the service entrance conductors are not in the meter can, they are in the CT can. The meter then displays the power used by calibration from the CTs and the reduction of the current in the service entrance to the current in the CT conductors to the meter. An example might be that there is 800 amps through the service entrance conductors, the CTs are 100:1, with the current in the conductors from the CTs being 8 amps, and it is that 8 amps which is run through the meter, which is then calibrated to read at 1:100 and the reading shows up as the actual power used based on the meter 'reading' the 800 amps being drawn through the service entrance conductors.

    However, back to your question: the conductors from the CTs and the service entrance conductors are not both in the meter can, both are only in the CT can.

    No conductors others than service entrance conductors are allowed to be run with the service entrance conductors - note in the above example that the conductors from the CTs are not 'run with' the service entrance conductors. The service entrance conductors exit through one raceway to the main disconnect and the conductors from the CTs exit through another raceway to the meter.

    Your scenario is not permitted by the code. As you were thinking - it is not proper.
    Jerry Peck - CodeMan
    AskCodeMan.com

    Construction and Litigation Consultant
    Construction Litigation Consultants, LLC.
    ConstructionLitigationConsultants.com
    User avatar
    Jerry Peck - Codeman
    Site Admin
     
    Posts: 1089
    Joined: Fri Dec 12, 2008 12:06 pm

    Re: Using meter can as a pas thru to load center

    New postby bigdog on Mon Feb 03, 2014 10:34 pm

    What does CT stand for?
    bigdog
     
    Posts: 47
    Joined: Thu Apr 12, 2012 10:54 pm

    Re: Using meter can as a pas thru to load center

    New postby Jerry Peck - Codeman on Tue Feb 04, 2014 12:17 am

    A CT is a current transformer.

    Visualize a donut where the donut is made from a flat band with it's ends connected to each other and with wire wrapped around the flat band which is now a circle (the donut).

    A conductor is run through the opening (the donut hole) and an ac current is flowing through the wire. That ac current creates a magnetic field around the conductor which expends and collapses with the ac current.

    The expanding and collapsing magnetic fields induces a current in the wire which is wrapped around the band of the donut. The amount of current in the donut coil is directly related to the amount of current in the conductor running through the donut coil (and depends on several factors, including the number of wraps of wire around the band of the donut coil).

    The current transformers can be constructed to fit various sized conductors with smaller diameter coils for smaller size conductors. The number of wraps can be adjusted to produce the ratio desired between the current in the coil and the current in the conductor.

    I've simplified the construction of the CT coils quite a bit but I believe it gives a visualization of a current transformer, how they are made and how they work.
    Jerry Peck - CodeMan
    AskCodeMan.com

    Construction and Litigation Consultant
    Construction Litigation Consultants, LLC.
    ConstructionLitigationConsultants.com
    User avatar
    Jerry Peck - Codeman
    Site Admin
     
    Posts: 1089
    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 2 guests



    www.AskCodeMan.com