Sealoffs on motors

[naplespete57]

Boy might I be missing it! Have been under the impression that all motors in Class 1 Div 1 area required sealoffs within 18". Was challenged on it recently and according to 501.15a I don't need a sealoff. Am I missing something?

 

[augie47]

My only concern would be 501.15(A)(1) -(2). I've not encountered a motor with "metric designator 53 (trade size 2) entry in a Classified area, but that wording would make me think a sealoff would be required.
Perhaps a poster more familar with Classified like Laszlo Z Weressil will show where it would not be (required).

 

[rbalex]

The challenge was valid to requiring seals as a general rule; although they are often sealed at stub-ups for boundary reasons. Augie’s comment about 501.15(A)(1)(2) is also valid.

Sections 501.125(A)(2) to (4) describe specific protection techniques for what are not usually explosionproof motors. Depending on the manner the motor terminal box is installed, 501.15(A) will need review.

Sections 501.125(A)(1) deals with explosionproof motors. Note it only mentions identified motors. Most explosionproof motors in this class are listed and have a factory seal between the motor housing and the motor terminal box. Again the motor terminal box will only need to be sealed as 501.15(A) may require. Some small motors, particularly single-phase, may not have the integral seal, they would need to be sealed under 501.15(A)(1)(1) specifically.