conduit connection to enclosure

[james_mcquade]

Hi everyone,

i have another question in regads to a class 2 div 2 environment.

in my earlier posting, i forgot to ask the following question.

the contractor we hired to build a machine for us used rigid conduit to go into
the wiretrough and enclosures. rather than using a myers hub, he placed a locknut onto the threads of the rigid conduit, then used a flat washer, and placed a rubber o-ring on the conduit next to the enclosure. he then used a second locknut on the insode of the enclosure to secure the conduit and conpress the o-ring.

i have never seen such an installation method before and i do not approve of it since the conduit can move and the seal be broken.

where in the code does it tell how to secure conduits to enclosures and wiretroughs?
also, is there a code reference for / against this method?

thanks in advance,
james

 

[rbalex]

See Section 502.30(A). I would strongly question the installation as you have currently described it.

 

[james_mcquade]

thanks bob,
james

 

[petersonra]

See Section 502.30(A). I would strongly question the installation as you have currently described it.

Something I have always wondered.

Does 502.30(A) require that all bonding means from the service point in the the classified area have to be of a certain type, or would it be acceptable for instance, to run a bonding wire from the service point to the classified area? How about if the bonding wire from the service point was spliced several times along the way?

 

[rbalex]

Something I have always wondered.

Does 502.30(A) require that all bonding means from the service point in the the classified area have to be of a certain type, or would it be acceptable for instance, to run a bonding wire from the service point to the classified area? How about if the bonding wire from the service point was spliced several times along the way?

The core issue, as many of our colleagues in these forums have recognized, is bonding rather than grounding.

Personally, I think the best overall summary of the requirements are in Section 250.100. However, 250.100 ultimately leads to 250.92(B)(4) and CMP14 wanted to emphasize that ??locknut-bushing and double-locknut types? of bonding, while they may be suitable for detection by overcurrent protection devices, have an inherent arcing potential and are not suitable in classified locations. Any arcs, no matter how they are created, have a significant potential of igniting materials in classified locations.

Section 250.100 answers your direct question:

One or more of these bonding methods shall be used whether or not supplementary equipment grounding conductors are installed.