class 1 division 2 conduit run

[boo33]

I have a question regarding NEC 501.15 (B)(2):

I have an outside conduit run that runs through a class 1 division 2 area (above ground). The run does contain unions as it passes through the classified area. I am sealed properly on one side of the area (as the conduit run exits the classified area). However, on the entry side into the classified area I do not have seals to minimize gas/vapor flow. The group classification for the area is group B. Unfortunately, wire has already been pulled through most of the conduit running through this area. As I read the exceptions to this NEC requirement I feel I may meet exception 4. There are 5 requirements that must ALL be met in order to use this exception. The fifth requirement for this exception says: "The conduit system segment is sealed at its entry to each enclosure or fitting housing terminals, splices, or taps in Class I, Division 2 locations."

Does this mean that I should be sealed at each entry to an enclosure or only at each entry to an enclosure if the enclosure houses terminals (terminations), splices, or taps?

Regarding Exception 2; what is defined as a ventilated busway? Additionally, if that requirement is met...the last part talks about the conduit not terminating at an enclosure containing an ignition source. Can someone help explain this as well?

Thanks in advance!

 

[danw2]

Comment on "ignition source":

I'm an instrument guy, not a master electrician, but any instrument that contains an electromechanical relay/contactor that does not have hermetically sealed contacts is considered an arcing/sparking device that qualifies as an ignition source and cannot be used in Div 2 areas.

There are relays and switches that are Div 2 rated. But the implication is that any enclosure with switch contacts, whether manual or remote operated (relay) that are not explicitly labled and rated Div 2 contains arcing/ sparking ignition sources.

Dan

 

[boo33]

Thanks for the reply. The enclosure located within the classied area does not contain any terminals, splices, contacts, etc. It is only used as a pull box.

Does anyone know what a conduit segment consists of, as referenced in exception 4(4)?