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Thread: Motors in Class 1 Div 2 Location

  1. #1
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    Motors in Class 1 Div 2 Location

    Would a single-phase motor that is appropriately rated for a Class 1 Div 2 location require a seal-off due to the motor having centrifugal switches or does the motors being rated for the area indicate the switching is sealed in such a manner to preclude the need for seal-offs ?
    At my age, I'm accustomed to restaurants asking me to pay in advance, but now my bank has started sending me their calendar one month at a time.

  2. #2
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    Quote Originally Posted by augie47 View Post
    Would a single-phase motor that is appropriately rated for a Class 1 Div 2 location require a seal-off due to the motor having centrifugal switches or does the motors being rated for the area indicate the switching is sealed in such a manner to preclude the need for seal-offs ?
    Forgive me Gus, but I'm having trouble wrapping my head around a single-phase motor being "... appropriately rated for a Class 1 Div 2 location ..." unless its explosionproof to begin with.

    If it is explosionproof AND the switches are in the motor housing AND there is a factory seal between the motor housing and the motor terminal housing AND there is a factory mark to the effect that the assembly is factory sealed THEN an additional external seal is not required for the motor.

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

  3. #3
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    Quote Originally Posted by rbalex View Post
    Forgive me Gus, but I'm having trouble wrapping my head around a single-phase motor being "... appropriately rated for a Class 1 Div 2 location ..." unless its explosionproof to begin with.

    If it is explosionproof AND the switches are in the motor housing AND there is a factory seal between the motor housing and the motor terminal housing AND there is a factory mark to the effect that the assembly is factory sealed THEN an additional external seal is not required for the motor.

    Edit Add: A seal for a non-explosionproof enclosure is useless.
    You have tolerated my weak knowledge of Hazardous enough over the years to know I can't even "speak hazardous" but that does not keep me from being thrown in the brier patch by the State.
    The motor is listed for hazardous locations and mounted in such a manner that I have not to date been able to read all the nameplate data. I will attempt to find such wording as to the presence of factory sealing.,
    Its a Corken IDEX LP pump.motor and Im still search their website for more specific info.
    At my age, I'm accustomed to restaurants asking me to pay in advance, but now my bank has started sending me their calendar one month at a time.

  4. #4
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    If it is listed for Class I only, it is suitable for both Division 1 and 2. [Section 500.8(C)(2)] I suspect it is explosionproof. I've linked to UL's guideinfo for LP-Gas Pumps. Note the statement:

    Pump-motor assemblies include electric motors and appropriate junction boxes suitable for use in Class I, Group D hazardous (classified) locations. [underline is mine]
    I also linked to Corken's UL online certification. It doesn't mention factory sealing. I suspect we would have to dig deeper into UL 51. I don't have that depth of access any longer.
    "Bob"
    Robert B. Alexander, P.E.
    Answers based on 2014 NEC unless otherwise noted.

  5. #5
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    Thanks, as always.
    Tracked the info down thru the manufacturer.. external seal-off is needed,.
    At my age, I'm accustomed to restaurants asking me to pay in advance, but now my bank has started sending me their calendar one month at a time.

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