Class 1 Div.2 XP pump

[aamsden]

I have a pump skid with 350 HP pump motor located in A class 1 Div.2 location. and a AB soft start in a unclassified area. The motor enclosure is rated EPFC or explosion proof. My question is this, I don't think the motor would have needed to be XP but it came with the skid. The motor is only 3ft. to the unclassified area. Can I run a piece of LFMC (liquidtight) with approved connectors 18" long into a non-explosion proof boundry seal and than a short RMC nipple going thru the wall into the unclassified area, or do I need an explosion proof seal because it is a XP rated motor?

Thanks

 

[rbalex]

My concern would be why the skid manufacturer supplied an explosionproof motor since a 350hp enclosure is incredibly expensive if it isn't necessary.

That said, if the manufacturer "just did it that way", then your proposed installation with properly bonded LFMC and a non-explosionproof boundary seal should be acceptable.

 

[aamsden]

XP motor

XP motor

Thanks Bob,
Without talking to my AHJ, when he comes to inspect and he decides it should be treated as an explosion proof motor, can I use sealoff at the motor and than still go with a piece of LMFC to go thru the wall. (Concerned about vibration ) or will I need a piece of explosion proof sealtight and another boundary seal. I'm a little confused here when I can use LMFC?

Thanks,
Al

 

[rbalex]

If the inspector insists on an explosionproof seal for the motor, you have a problem even if you have several options.

It's a strange situation that Division 2/unclassified boundary seals don't have to be explosionproof but the rest of the wiring method between the seal and the boundary must be RMC or IMC. I really don't believe CMP14 thought through the implications of Section 501.15(B)(2) when they dropped the requirement for explosionproof boundary seals. None of the Exceptions apply to the installation you described.

That said, you can't use LFMC between the seal and the boundary. You can use a flexible explosionproof coupling between the motor terminal box and the explosionproof seal. If it is judiciously located, the explosionproof seal can do "double duty" as the boundary seal.