Motors in Class 1 Div 2 Location

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augie47

augie47

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Tennessee
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State Electrical Inspector (Retired)
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 ?
 
augie47 said:
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 ?
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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.
 
rbalex said:
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.
Click to expand...

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.
 
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]
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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.
 
Thanks, as always.
Tracked the info down thru the manufacturer.. external seal-off is needed,.
 
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