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Joined: Mar 2005
Posts: 48
Fourteen 1-1/4 inch conduits from a buried ductbank are entering an underground vault about 30'long x 20'wide x 20' high, classified Class I Div 2 hazardous area. Want to built the conduit system in a neat, workmanship like manner.

The entering conduits originate in an unclassified, above ground electrical space.

Conduit seals are required inside the underground vault near the wall penetrations before the conduit leaves the space.

The conduit inside the vault will be for feeders and control cables to electrical equipment and lighting.

If the seal is placed at the conduit penetration, the seal will be perpendicular to the wall and protrude into the room a few inches. This requires an elbow and a few conduit bends to bring the conduit against the wall when run parallel to the wall. This arrangement doesn't look to good to me because it protrudes into the room too much.

An elbow could be installed first on the "stub" into the room to put the conduit parallel to the wall, and then install the seal. But this method requires enough space between conduit stubs for installing the elbows.

How would you build the conduit entrance into the vault to minimize the distance between the conduit stubs and the space between the conduit and the vault wall as the conduit is routed parallel to the walls when run to the equipment?

Joined: Jul 2002
Posts: 680
Doesn't the seal have to be the first fitting into the vault??
Do you want the conduit to be heading upwards once it enters the vault?? why not bend the conduit so it does that, place the seal on the first thread??

Joined: Jan 2005
Posts: 5,316
Cat Servant
First of all, check the Crouse-Hinds and Appleton catalogs; there are "elbow seals" made that just might work for you.

I would not try to get the pipe flush against the wall; this is an appication that screams for the use of strut.

If space is that tight, perhaps it would be better to relocate the seals to a point outside the 'zone,' then run the pipe to exactly where it is needed.

Joined: Jul 2002
Posts: 680
"elbow seals" or plugged ells would work if you want the direction of the pipe to be straight down.

Joined: Mar 2005
Posts: 48
The sealing elbow sounds like a good idea to me. Unfortunately, the only elbow type seal I've been able to locate is a 3/4" from Crouse-Hinds. The on-line catalogs from Killark, Appleton, Thomas&Betts, and others don't list a sealing elbow, only straight elbows.

Are there any suggestions where I might find the 1-1/4 inch variety?

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