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Cable Seals 501.15(E)

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    #16
    Originally posted by rbalex View Post
    The first sentence of Subsection 501.15(D)(1) states the "where" all cables must be sealed. It makes no distinction about the Type of enclosure or its features or the Type of cable itself. The rest of Subsection 501.15(D) and subsequent Subsections, including the Exceptions, deal with the "how" for sealing various Types of cables and their constructions and enclosure features don't matter much within the context of Class I, Division 1; i.e., cables still must be sealed at the terminations.

    That said, the first two bullets are fine. The third bullet is problematic since Type TC (of any kind) must still be sealed at the terminations. It is permitted to omit boundary seals for Type TC and other constructions but not the conduit.
    Third Bullet: Ok, so CID1, TC cable ends still needs to be sealed at the Factory Sealed enclosure - fine. This basically brings me right back to installing a conduit seal, i.e. C-H EYD at the control station - correct?
    If the cable were single conductors instead of TC, could the seal then be omitted per Article 501.15(A)(1) Exception b?

    Also if it were CID2, same scenario, I assume TC cable would NOT have to be sealed at the termination for the Factory Sealed device?

    Thanks again, in advance.
    Dale

    Comment


      #17
      Originally posted by Dale001289 View Post
      Third Bullet: Ok, so CID1, TC cable ends still needs to be sealed at the Factory Sealed enclosure - fine. This basically brings me right back to installing a conduit seal, i.e. C-H EYD at the control station - correct?
      If the cable were single conductors instead of TC, could the seal then be omitted per Article 501.15(A)(1) Exception b?

      Also if it were CID2, same scenario, I assume TC cable would NOT have to be sealed at the termination for the Factory Sealed device?

      Thanks again, in advance.
      Dale
      Note the first sentence of Subsection 501.15(D)(1) says nothing about single nor multiconductor tables. To be genuinely horrified read Section 501.15 Informational Note No. 2. Be grateful there's no enforceable language.

      This was a topic of some discussion some years back. It was considered by several CMP14 members that simply sealing the end of a multiconductor cable with a mastic filled heatshrink tube would be “suitable” [500.8(A)]and a factory sealed device wouldn’t require an external conduit seal. In fact,we had discussions with most of the major heatshrink manufacturers and were assured there would be no problem making such a product. The NRTLs were a bit concerned about the product testing though and we weren’t quite able to agree on wording either

      Ultimately, we wimped out and said it wasn’t too common a practice to use multiconductor cables in conduit in Division 1. That is generally true for power, less so for instrumentation; nevertheless, it was dropped.

      As for revising bullet three for a Class I, Division 2 application, you are correct.
      "Bob"
      Robert B. Alexander, P.E.
      Answers based on 2017 NEC unless otherwise noted.

      Comment


        #18
        Originally posted by rbalex View Post
        Note the first sentence of Subsection 501.15(D)(1) says nothing about single nor multiconductor tables. To be genuinely horrified read Section 501.15 Informational Note No. 2. Be grateful there's no enforceable language.

        This was a topic of some discussion some years back. It was considered by several CMP14 members that simply sealing the end of a multiconductor cable with a mastic filled heatshrink tube would be “suitable” [500.8(A)]and a factory sealed device wouldn’t require an external conduit seal. In fact,we had discussions with most of the major heatshrink manufacturers and were assured there would be no problem making such a product. The NRTLs were a bit concerned about the product testing though and we weren’t quite able to agree on wording either

        Ultimately, we wimped out and said it wasn’t too common a practice to use multiconductor cables in conduit in Division 1. That is generally true for power, less so for instrumentation; nevertheless, it was dropped.

        As for revising bullet three for a Class I, Division 2 application, you are correct.
        They've routed TC-ER into sump pits (CID1) via rigid aluminum conduit; placed boundary seals correctly, but failed to seal the cable ends per 501.15(D)(1), (i.e.using conduit seals), at the control stations AND the motor termination boxes.
        Really appreciate the feedback.

        Comment


          #19
          Originally posted by rbalex View Post
          Note the first sentence of Subsection 501.15(D)(1) says nothing about single nor multiconductor tables. To be genuinely horrified read Section 501.15 Informational Note No. 2. Be grateful there's no enforceable language.

          This was a topic of some discussion some years back. It was considered by several CMP14 members that simply sealing the end of a multiconductor cable with a mastic filled heatshrink tube would be “suitable” [500.8(A)]and a factory sealed device wouldn’t require an external conduit seal. In fact,we had discussions with most of the major heatshrink manufacturers and were assured there would be no problem making such a product. The NRTLs were a bit concerned about the product testing though and we weren’t quite able to agree on wording either

          Ultimately, we wimped out and said it wasn’t too common a practice to use multiconductor cables in conduit in Division 1. That is generally true for power, less so for instrumentation; nevertheless, it was dropped.

          As for revising bullet three for a Class I, Division 2 application, you are correct.
          Art 501.15(A)(1) Exceptions a-b, lead you to believe conduit seals can be omitted. But when you look at 501.15(D) - especially when routing TC cable in conduit - you're right back to installing the conduit seal regardless, AND there doesn't seem to be any cross-referencing between the two Articles. Is it just me, or is this an area of the code that deserves clarification on the next cycle?

          Comment


            #20
            Originally posted by Dale001289 View Post
            Art 501.15(A)(1) Exceptions a-b, lead you to believe conduit seals can be omitted. But when you look at 501.15(D) - especially when routing TC cable in conduit - you're right back to installing the conduit seal regardless, AND there doesn't seem to be any cross-referencing between the two Articles. Is it just me, or is this an area of the code that deserves clarification on the next cycle?
            So make a Public Input. You're running out of time though.
            Last edited by rbalex; 08-30-17, 03:05 AM. Reason: Added link to NFPA Public Input.
            "Bob"
            Robert B. Alexander, P.E.
            Answers based on 2017 NEC unless otherwise noted.

            Comment


              #21
              Originally posted by rbalex View Post
              So make a Public Input. You're running out of time though.
              I'm yanking your chain again although it's still a good idea to learn how to make a Public Input.

              Technically, stranded conductors are cables and solid conductors are not. See Webster’s Collegiate Dictionary, 11th edition definition of cable. (Definition 1 as opposed to 3). Webster’s Collegiate Dictionary, 11th edition, is NFPA's "official" dictionary when words are not defined within the context of an NFPA standard or standards. Fortunately, Merriam-Webster's online edition uses identical definitions.

              You might suggest that the first sentence of Subsection 501.15(D)(1) be revised to read, "Multiconductor cables shall be sealed with sealing fittings that comply with 501.15(C) at all terminations."
              "Bob"
              Robert B. Alexander, P.E.
              Answers based on 2017 NEC unless otherwise noted.

              Comment


                #22
                Originally posted by rbalex View Post
                I'm yanking your chain again although it's still a good idea to learn how to make a Public Input.

                Technically, stranded conductors are cables and solid conductors are not. See Webster’s Collegiate Dictionary, 11th edition definition of cable. (Definition 1 as opposed to 3). Webster’s Collegiate Dictionary, 11th edition, is NFPA's "official" dictionary when words are not defined within the context of an NFPA standard or standards. Fortunately, Merriam-Webster's online edition uses identical definitions.

                You might suggest that the first sentence of Subsection 501.15(D)(1) be revised to read, "Multiconductor cables shall be sealed with sealing fittings that comply with 501.15(C) at all terminations."
                Thanks again Bob, as always great input.

                Comment

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