Sewer lift Station C1 D1 to C1 D2 Motor power,control cable connections

[alfreduran4]

We have an explosion-proof submersible motor located inside a wet well which
is classified Class 1 Division 1. The cable type for both the power and control cables
are SOOW cable. What I would like to know is if the Nema 4x Stainless Steel
enclosure a Class 1 Division 2? Which I'm sure is or else the enclosure would be
rated explosion-proof. If it is Class 1 Division 2, can the power and control cables
run along the ground in a Stainless Steel expanded metal grating up to the Nema
4x enclosure using the same expanded metal grating creating a atmospheric seperation
between the C1 D1 to the C1 D2? Or does it have to be encased in RMC?
Also do we need to seal the power and control cables running into the Nema 4x enclosure?
I have attached an old drawing where this was done but not sure if the current NEC 2011
still allows us to do it the way it was then. Thank you. Any questions or comments are
welcomed.

 

[rbalex]

If the disconnect is located in a Class I, Division 2 location, an enclosure rated Type 4 only is unacceptable. Cable seals would be required at an acceptable (explosionproof) enclosure.

Expanded metal may be acceptable for mechanical protection but it provides absolutely no "... atmospheric separation [sic]
between the C1 D1 to the C1 D2."

Not only would the 2011 NEC prohibit this installation, it would never have be consistent with any Code current at the time.

 

[alfreduran4]

Thanks for your reply rbalex. Is there a distance where a Nema 4x enclosure would be allowed
and we do not need to seal the cable glands to the enclosure? We need to be able to pull the whole entire run of cables in case we need to do maintenance to the motor.

 

[rbalex]

... Is there a distance where a Nema 4x enclosure would be allowedand we do not need to seal the cable glands to the enclosure? ...

No. See Section 501.15 (D)(1). Basically, as long as the cable originates in Division 1, it must be sealed at all terminations. Since the cables are not MC-HL, only the first sentence applies. Since the cables are not in conduit, Sections 501.15 (D)(2) and (3) don't apply.

 

[cpinetree]

Take a look at this thread: http://forums.mikeholt.com/showthread.php?t=145603

I know it is not exactly your situation, but they were able to steer the AHJ into allowing and explosion proof J box, before the sealoff, so pumps could be changed.

It definitely does not meet the letter of the code. But, I can see the reasoning behind it, because we see it often enough (the sealoff was dug out and never repoured after a pump change).