Conduit Seal Location Requirements

[DM2-Inc]

Is it permissible to install a conduit seal, for a Class I, Div 2, location such that it connects two (2) junction boxes in line with the conduit, where the farthest junction box is no more than 18" from the seal?


----(Conduit)---(S)---[j-box 1]---[j-box 2]

Distance from "(S)" (conduit seal) to "j-box 2" is 18" or less

I want to say it's not permitted due to potential pressure piling inside of the boxes and conduit?

Regards,
Dan

 

[don_resqcapt19]

Assuming that the junctions boxes require seals, which is not always the case for Class I, Division 2 locations, I see nothing in the code that would permit you to make the installation as shown. The only fittings permitted between a box that is required to be sealed and the seal are "explosionproof unions, couplings, reducers, elbows, capped elbows, and conduit bodies similar to L, T, and Cross types that are not larger than the trade size of the conduit". You could install a T between the two boxes and a single seal on the other outlet of the T, but you can't have a second junction box between the first box and the seal.

 

[DM2-Inc]

Each junction box is used to make wire connections for two (2) Class I, Div 2 strobe lights. The strobe lights aren't sealed themselves and therefore require a conduit seal within 18 inches.

So it's acceptable for the two (2) junction boxes to be on either side of the "T" without a seal, and install the seal on the bull of the "T"?

...(Sorry guy's, don't know how to put a picture in the body of a message).

Regards,
Dan

 

[don_resqcapt19]

Each junction box is used to make wire connections for two (2) Class I, Div 2 strobe lights. The strobe lights aren't sealed themselves and therefore require a conduit seal within 18 inches.

So it's acceptable for the two (2) junction boxes to be on either side of the "T" without a seal, and install the seal on the bull of the "T"?

...(Sorry guy's, don't know how to put a picture in the body of a message).

Regards,
Dan

Yes your picture would meet the code rules. It appears to me that the junction boxes do not require seals and only the strobe lights do. That would require the seal to be between the strobe light and the junction box, unless the junction box you are talking about is part of the strobe light.