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Thread: Conduit entering in Manhole

  1. #1
    Join Date
    May 2018
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    Los Angeles
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    Conduit entering in Manhole

    Hello Sir/Madam,

    I have a conduit coming out of an equipment. Equipment is in Class 1 Area 1. Conduit is sealed at equipment end. Same conduit later enter in a Manhole ( about 20'). Do I need to take any precaution with manhole, like seal in Manhole or explosion proof Manhole. Manhole is out of Classification area. Please advise.

    Thank you.

  2. #2
    Join Date
    Apr 2004
    Location
    Mission Viejo, CA
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    5,204
    Quote Originally Posted by smarteng View Post
    Hello Sir/Madam,

    I have a conduit coming out of an equipment. Equipment is in Class 1 Area 1. Conduit is sealed at equipment end. Same conduit later enter in a Manhole ( about 20'). Do I need to take any precaution with manhole, like seal in Manhole or explosion proof Manhole. Manhole is out of Classification area. Please advise.

    Thank you.
    First, we are going to assume you mean Class I, Division 1. If that is not true you need to clear it up.

    Second, we are going to assume that no Article from 511 to 515 applies. Again, if that assumption is not correct you need to clear it up.

    Third, we will assume the seals in the Class I, Division 1 location and at the boundary, if the equipment seal[s] don’t do double duty, are properly installed.

    Fourth, we assume you are certain there is no Division 2 that encloses the Division 1 location and it extends above the manhole. At 20’ from the Division 1, location a Division 2 location above the manhole would be expected.

    If the assumptions are correct, nothing special needs to be done in the manhole.
    "Bob"
    Robert B. Alexander, P.E.
    Answers based on 2014 NEC unless otherwise noted.

  3. #3
    Join Date
    May 2018
    Location
    Los Angeles
    Posts
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    Thank you so much for the reply.

    1. My Bad, it is class I Div 1.
    2.
    3. Yes All Class 1 Div 1 equipment conduits are Sealed
    4. No Class 1 Div 2 exist over Manhole.

    Regards.

  4. #4
    Join Date
    Apr 2004
    Location
    Mission Viejo, CA
    Posts
    5,204
    Quote Originally Posted by smarteng View Post
    Thank you so much for the reply.

    1. My Bad, it is class I Div 1.
    2.
    3. Yes All Class 1 Div 1 equipment conduits are Sealed
    4. No Class 1 Div 2 exist over Manhole.

    Regards.
    1 The "C" in "Class" is capitalized.
    3&4 For hazardous locations "Class" is designated with Roman numerals: I, II, III

    No big, but if you are going to be a smart engineer, you should know.
    "Bob"
    Robert B. Alexander, P.E.
    Answers based on 2014 NEC unless otherwise noted.

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