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Thread: Class 1 Division 2 Conduit Seals (Again)

  1. #1
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    Class 1 Division 2 Conduit Seals (Again)

    I know this is a vague question, but that is somewhat intentional.

    When a piece of equipment has a CSA Class 1 Division 2 certification, what conduit seals (if any) are required at the device?

    Assuming a conduit installation, does one need to install a seal at the equipment?

    Paraphrasing NEC 501.15 (B)(1), connections to enclosures required to be explosion proof require a seal. BUT it doesn't say anything about enclosures that are not required to be explosion proof.

    Does this mean no conduit seal is required at the equipment?

  2. #2
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    Quote Originally Posted by jstpie5 View Post
    I know this is a vague question, but that is somewhat intentional.

    When a piece of equipment has a CSA Class 1 Division 2 certification, what conduit seals (if any) are required at the device?

    Assuming a conduit installation, does one need to install a seal at the equipment?

    Paraphrasing NEC 501.15 (B)(1), connections to enclosures required to be explosion proof require a seal. BUT it doesn't say anything about enclosures that are not required to be explosion proof.

    Does this mean no conduit seal is required at the equipment?
    The first question I would ask would be is a CSA certification appropriate.

    One might not need a seal at the box but I think one still needs a boundary seal.
    Bob

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    I suppose the CSA certification is a bit of an unintentional red herring.

    The particular component I am looking at has a CSA Class 1 Div 2 rating. The certification states "The products listed below are eligible to bear the CSA Mark shown with adjacent indicators 'C' and 'US' for Canada and US or with adjacent indicator 'US' for US only or without either indicator for Canada only." and has a "C" and "US" indicator.

    I agree that a seal is needed at the boundary per 501.15(B)(2), but I am still unclear on the conduit sealing requirements at the device.

  4. #4
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    Quote Originally Posted by jstpie5 View Post
    I suppose the CSA certification is a bit of an unintentional red herring.

    The particular component I am looking at has a CSA Class 1 Div 2 rating. The certification states "The products listed below are eligible to bear the CSA Mark shown with adjacent indicators 'C' and 'US' for Canada and US or with adjacent indicator 'US' for US only or without either indicator for Canada only." and has a "C" and "US" indicator.

    I agree that a seal is needed at the boundary per 501.15(B)(2), but I am still unclear on the conduit sealing requirements at the device.
    Two questions:

    1. Is the enclosure explosionproof?
    2. Is it required to be?
    "Bob"
    Robert B. Alexander, P.E.
    Answers based on 2014 NEC unless otherwise noted.

  5. #5
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    Quote Originally Posted by rbalex View Post
    Two questions:

    1. Is the enclosure explosionproof?
    2. Is it required to be?

    The first question is easy - No the enclosure is not explosionproof.

    The second question not so easy. My thinking is that it is not required to be explosionproof since the manufacturer doesn't state that it is explosionproof yet it is suitable for installation in a class 1 division 2 location.

    What does this Class 1 Division 2 rating on a piece of equipment mean (flow transmitter in this case)?

    Does it mean that it can be installed in a Class 1 Division 2 location but it's not explosionproof?
    Last edited by jstpie5; 04-11-18 at 01:19 PM.

  6. #6
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    If the device is not explosion proof but is listed for a particular Class and Division, that indicates to me that it is not considered to be a potential ignition source. That might be because it has no power source connected to it or because any sparking components are hermetically sealed inside the unit.
    Explosion proof is generally not gas-tight or ignition source free but rather in the event of an explosion decreases the temperature of any internal combustion products before they get outside the component.

    Sent from my XT1585 using Tapatalk

  7. #7
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    Quote Originally Posted by jstpie5 View Post
    The first question is easy - No the enclosure is not explosionproof.

    The second question not so easy. The device is claims to be rated for installation in a class 1 division 2 location, but is not labelled explosionproof.

    What does a Class 1 Division 2 rating on a piece of equipment mean (flow transmitter in this case)?

    Does it mean that it can be installed in a Class 1 Division 2 location but its not explosionproof?
    If it's not explosionproof, Section 501.15(B)(1) doesn't apply with respect to sealing, whether it's required to be or not.

    Answering the second part is tougher. First, I want to make it clear that I have a tremendous respect for CSA, so the rest of what I'm about to say may appear that isn't the case.

    Though very similar, Canadian rules are still different from NEC, especially with respect to Classified locations. Where Canadian Division 2 applies, CSA lists everything. Read the "Certificate of Compliance" carefully. Only the UL Standards apply to the "US" part of the certificate, the CSA Standards are meaningless with respect to the NEC or, more importantly, OSHA.

    Based on your previous thread, the product may be used in a properly documented nonincendive system without a seal.
    "Bob"
    Robert B. Alexander, P.E.
    Answers based on 2014 NEC unless otherwise noted.

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    Quote Originally Posted by rbalex View Post
    Based on your previous thread, the product may be used in a properly documented nonincendive system without a seal.
    Thanks again for the input. Very good point about the Certificate of Compliance not referencing NEC.

    Interestingly enough, this device is different from the device in my previous thread or I would have just added to that one. Unfortunately, this particular device (MicroMotion 2400SIA11B2EZZZ) does not make any mention of nonincendive outputs or intrinsically safe outputs.

    Sounds to me like there's not much I can do to equate a UL standard to NEC requirements.

  9. #9
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    Quote Originally Posted by jstpie5 View Post
    ...
    Sounds to me like there's not much I can do to equate a UL standard to NEC requirements.
    By citing CSA Standard C22.2 No. 213-M1987. It does appear CSA intends for the product to be used in a nonincendive system.

    EDIT ADD: A seal on a non-explosionproof enclosure is useless.
    "Bob"
    Robert B. Alexander, P.E.
    Answers based on 2014 NEC unless otherwise noted.

  10. #10
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    I also concur with goldigger's comments. If the device is listed specifically for Division 2, then it isn't explosionproof but complies with a protection technique that is suitable. See Sections 500.7, 500.8, and 501.10(B)(4).
    "Bob"
    Robert B. Alexander, P.E.
    Answers based on 2014 NEC unless otherwise noted.

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