Class 1, Div. 1 enclosures

[mark0502f]

We are manufacturing a piece of equipment that will be installed in a Class 1, Division 1 location. The equipment has a local control station (with switches, pushbuttons, etc) and a cable operated emergency stop switch. Both enclosures and all pilot devices are rated for this classification. We intend to locate them within about 6 inches of each other, and route the wiring from the E-Stop to the terminal strip in the local control station via a union and two close nipples. Is a seal required between the two enclosures, since they are located within 18" of each other? There will be a seal where the wiring leaves the local station.

 

[petersonra]

(3) Two or More Explosionproof Enclosures. Where two
or more explosionproof enclosures for which conduit seals
are required under 501.5(A)(1) are connected by nipples or
by runs of conduit not more than 900 mm (36 in.) long, a
single conduit seal in each such nipple connection or run of
conduit shall be considered sufficient if located not more
than 450 mm (18 in.) from either enclosure.

 

[mark0502f]

Does this apply since the E-Stop will be within 18" of the EYS from the outlet of the local station?

 

[petersonra]

Does this apply since the E-Stop will be within 18" of the EYS from the outlet of the local station?

The conduit seal is to seal the conduit. If there is a piece of conduit entering an XP box, it needs a seal (generally).

You can have a piece of conduit up to 36" long between two XP boxes that has just one seal in it right in the middle.

In other words, one seal in the short piece of conduit can seal the conduit to both boxes.

 

[mark0502f]

Thanks for the quick reply. We weren't really sure of the intent of this paragraph.