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Thread: Exposed, outdoor-rated intrinsically safe wire or cable

  1. #11
    Join Date
    Apr 2004
    Location
    Mission Viejo, CA
    Posts
    4,875
    I started to write an essay and long history lesson - I'm just too tired to do that. I'm simplifying this as much as I can.

    Basically, start in Sections 725.125, 127, and 130. You might also review the definitions of Class 2 Circuits and Class 3 Circuits. The key element to defining Class 2 Circuits and 3 Circuits is the power supply, not the wiring method. Cables and wiring methods listed in Section 715.135 and following are simply permissible alternates to those in Chapter 3 for Class 2 and 3 Circuits

    A brief history. Article 727 was written specifically to avoid most of the crap in Article 725; especially several dubious separation requirements. Type ITC isn't Type PLTC although it is conceivable a given cable may have a dual identification.

    "Protected against physical damage" is such a broad concept that it's almost impossible to clearly define what is and what isn't. Depending on the traffic it is exposed to, RMC wiring may still be exposed to physical damage; whereas lighter wring methods may be fine by an isolated location.
    "Bob"
    Robert B. Alexander, P.E.
    Answers based on 2014 NEC unless otherwise noted.

  2. #12
    Join Date
    Jun 2004
    Posts
    14

    Comment and links to manufacturing

    VITALink® FieldBus Fire Resistive FieldBus Cable 90°C / 75°C*, 600 Volt NEC Type TC-ER CEC Type CIC & TC UL Listed CUL Listed RSS-5-158

    http://www.r-scc.com/files/Catalog%2...20FieldBus.pdf

    http://control.com/thread/1258218534

  3. #13
    Join Date
    Jul 2017
    Location
    Alberta, Canada
    Posts
    15
    Bob: Articles 725 and 727 are currently impenetrable to me; I lack the necessary background. I especially don't see how 727 applies when "ITC is not PLTC". I'll just have to take your word for it.

    nec_addicted: Thanks for the suggestion! Hopefully we can make something work.

  4. #14
    Join Date
    Apr 2004
    Location
    Mission Viejo, CA
    Posts
    4,875
    Quote Originally Posted by IntrinsicSafety View Post
    Bob: Articles 725 and 727 are currently impenetrable to me; I lack the necessary background. I especially don't see how 727 applies when "ITC is not PLTC". I'll just have to take your word for it..
    Sorry, so I will be blunt. For your application, Type ITC installed per Section 727.4(4) or (5) will work; Type PLTC installed per Section 725.135(J) will work; OR Type TC installed per Section 336.10(7) will work.

    Quote Originally Posted by IntrinsicSafety View Post
    ...
    nec_addicted: Thanks for the suggestion! Hopefully we can make something work.
    This is a reason I usually avoid Intrinsically Safe (IS) systems if I can. By the time all the bells have been rung, all the whistles have been blown, and all the hoops have been jumped through, IS is rarely cost effective after the additional requirements of Sections 504.10, 50, 60, and 70 have been addressed just to avoid Sections 501.10(A) or (B) - and honestly, it isn't that much safer as the link to the control.com thread attests.
    "Bob"
    Robert B. Alexander, P.E.
    Answers based on 2014 NEC unless otherwise noted.

  5. #15
    Join Date
    Jul 2017
    Location
    Alberta, Canada
    Posts
    15
    Hi Bob,

    Thanks for being blunt, I appreciate it. :-) The information is very helpful, thanks!

    I wouldn't give this project much weight when judging intrinsic safety vs. other applications. This one is off-the-charts bizarre.

    I kind of like IS, but that's just me. It's not always the best thing but sometimes you don't really have an option.

    Thanks again!

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