Class I, Div 1 Seals for Large Motors?

[rjmeitner]

501.15(A)(1) requires conduit seals "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 size 53 (trade size 2) or larger and the enclosure contains terminals, splices, or taps."

Question 1) Does the first condition apply to an explosionproof induction motor so that a seal-off is required before the termination enclosure on the side of the motor?

Question 2) If the motor termination enclosure has a 2" opening and an R/E is installed for 1-1/2" conduit, is the "entry" considered to be 2" or 1-1/2" for condition 2?

 

[Bill W]

Is the entry threaded, and being reduced by threaded reducer, or only reduced by washers?

 

[Smart $]

re Q1: No. The first condition does not apply to the termination box, as the leads are hermetically sealed at the motor housing, TTBOMK.

re Q2: I would consider the entry to be 1 1/2", provided you mean by RE a threaded reducing bushing. To me, an RE is such, but I've heard other electricians call reducing washers RE's...

 

[rjmeitner]

Thanks for the responses! The R/E is threaded inside and out. It's not a washer.