fitting & enclosures for class 2 div 2

[wyerdup]

I have a project in a feed mill and most of the building is class 2 div 2. My question is, do standard fittings with gasketed covers (LB's & T's) meet the dusttight requirement of the NEC? Also it appears that I can use NEMA 12 boxes, but I am unsure if I am permitted to make slices in that type of enclosure. The handbook explanation for 502.10b4 indicates no splices, but the code section really only sayes boxes must be dusttight.

 

[resqcapt19]

The code requirement is only for "dust tight" for both the fittings and junction boxes in a Class II, Division 2 location. I don't have a copy of the 2008 handbook here, but the comment after 502.10(B)(4) in the 2005 handbook addresses a Divison 1 location and not a Division 2 location.

 

[JLSeagull]

2008 NEC 502.10(B)(4)
(4) Boxes and Fittings. All boxes and fittings shall be dusttight.

2008 Explanation
In Division 1 locations, boxes containing taps, joints, or terminal connections must be dusttight, must be provided with threaded hubs, as shown in Exhibit 502.1, and must be identified for use in Class II locations. Threaded hubs also provide adequate bonding in Division 2 locations (see Exhibit 502.1).

Exhibit 502.1 also shows a close-fitting cover, which is required for Class II locations. Standard pressed-steel boxes that are not identified for Class II locations are permitted as long as they do not contain taps, joints, or terminal connections, are dusttight, and are provided with a bonding jumper around the box in order to compensate for the absence of threaded hubs.