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Thread: class 1 div1

  1. #1
    Join Date
    Sep 2008
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    14

    Question class 1 div1

    In class 1 div1 if I come out of an explosion proof box to a device (non arcing) do I have to have a seal between the listed explosion proof box and the device? can you use flexible nonmetallic conduit for the connection?

  2. #2
    Join Date
    Jul 2008
    Location
    owensboro, ky
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    I am currently working for a natural gas transmission company and they follow the NEC very closely. That being said I don't have my NEC in front of me, but when constructing anything in class 1 div 1 area we use seal offs everywhere.
    Example: I have a temperature transmitter on a gas pipeline connected to it is a sealoff next FMC which connects directly to a listed explosion proof box then another sealoff which connects to RMC going to a meter building.
    Hope thats not too confusing.
    I was going to attach a schematic but couldn't get the size down small enough.:-?

  3. #3
    Join Date
    Feb 2003
    Location
    Illinois
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    18,571
    Quote Originally Posted by ronlove
    In class 1 div1 if I come out of an explosion proof box to a device (non arcing) do I have to have a seal between the listed explosion proof box and the device? can you use flexible nonmetallic conduit for the connection?
    You can't use flexible nonmetallic conduit in a Class I, Division 1 location. A seal will not be required at the enclosure if the conduit is smaller than 2" and there are no apparatus, such as switches, circuit breakers, fuses, relays, or resistors, that may produce arcs, sparks, or high temperatures that are considered to be an ignition source in normal operation
    Don, Illinois
    "It is the first responsibility of every citizen to question authority." B Franklin

  4. #4
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    Mar 2008
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    Oklahoma
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    Quote Originally Posted by don_resqcapt19
    You can't use flexible nonmetallic conduit in a Class I, Division 1 location. A seal will not be required at the enclosure if the conduit is smaller than 2" and there are no apparatus, such as switches, circuit breakers, fuses, relays, or resistors, that may produce arcs, sparks, or high temperatures that are considered to be an ignition source in normal operation
    Ok, my art 500 head is old, but I wouldnt think that you can leave a exp enclosure without sealing the conduit at the first thread out, OR, if you attach another exp enclosure with no threaded junctions.....where am I loosing what you saying? In my mind you can't leave the exp proof enclosure opening unsealed no matter what the size....can you give me a code reference?
    "Mule"

    Yes, Im stubborn as a mule..that's why,
    I'm a "Has Been" that "Never Was"
    :D

  5. #5
    Join Date
    Feb 2003
    Location
    Illinois
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    Mule,
    Take a look at 501.15(A)(1) in the 2008 code.
    (A) Conduit Seals, Class I, Division 1. In Class I, Division 1 locations, conduit seals shall be located in accordance with 501.15(A)(1) through (A)(4).
    (1) Entering Enclosures. In each conduit entry into an explosionproof enclosure where either of the following apply:
    (1) The enclosure contains apparatus, such as switches, circuit breakers, fuses, relays, or resistors, that may produce arcs, sparks, or high temperatures that are considered to be an ignition source in normal operation.
    (2) The entry is metric designator 53 (trade size 2) or larger and the enclosure contains terminals, splices, or taps. ...
    Don, Illinois
    "It is the first responsibility of every citizen to question authority." B Franklin

  6. #6
    Join Date
    Mar 2008
    Location
    Oklahoma
    Posts
    1,737
    Quote Originally Posted by don_resqcapt19
    Mule,
    Take a look at 501.15(A)(1) in the 2008 code.
    Thanks, I look at it this evening..............
    "Mule"

    Yes, Im stubborn as a mule..that's why,
    I'm a "Has Been" that "Never Was"
    :D

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