Class 1 Div 2 Gr D Conduit Questions

[EKhan]

We have a Pump skids in Class 1 Div 2 and Gr D location with Explosion proof motors and class 1 Div 2 rated pressure switches. There is a Explosion proof (NEMA 7) Junction box with Start/Stop switches and pilot lights. The skid fabricator used Thomas Bette PVC coated rigid steel conduit and ordinary purpose conduit fittings (Form 7, such as 90 degree elbows) to run wiring between motor (s) and Junction box. Can you please advise if these ordinary purpose fittings and rigid threaded PVC coated conduits are acccpetable for Class 1 Div 2 Gr D location. Also advise what kind of sealing/Bonding required at the junction box termination point.

Thanks

EK

 

[Rockyd]

If it is a skid mounted unit, other than your hook up, I don't believe that subjects the unit to inspection. In the name of safety though, might want to take a look at the unit to see if you can spot any unsafe conditions that warrant an RFI, or Change order, after the appropriate amount is determined.

Sealoff with a union, for disconnection of unit might be smart without seeing unit.

 

[rbalex]

We have a Pump skids in Class 1 Div 2 and Gr D location with Explosion proof motors and class 1 Div 2 rated pressure switches. There is a Explosion proof (NEMA 7) Junction box with Start/Stop switches and pilot lights. The skid fabricator used Thomas Bette PVC coated rigid steel conduit and ordinary purpose conduit fittings (Form 7, such as 90 degree elbows) to run wiring between motor (s) and Junction box. Can you please advise if these ordinary purpose fittings and rigid threaded PVC coated conduits are acccpetable for Class 1 Div 2 Gr D location. Also advise what kind of sealing/Bonding required at the junction box termination point.

Thanks

EK

Assuming the location is properly classified, there is no inherent problem with using the Form 7 conduit bodies.

The junction box is a bit more problematic and depends on the nature of the switches, pilot lights and other potential, arcing, sparking or heat (ASH) producing devices inside. Again assuming there are only terminations and no additional ASH devices inside, the switches and pilot lights should be reviewed to determine if they are factory sealed or otherwise suitable for Division 2. Many are and, if so, there should be no further concerns. However, if a single ASH device is in the enclosure or any of the switches and lights are not factory sealed or otherwise suitable for Division 2, then each conduit entering the box must be sealed within 18? of the box as measured along the raceway. The Form 7 fittings are still acceptable though.

If it turns out the seals are unnecessary, then the JB didn?t need to be NEMA 7. Any suitable outdoor enclosure would have been acceptable. Depending on the motors design it probably never needed to be explosionproof.

 

[EKhan]

Class 1Div2 Gr D Conduit Questions

Class 1Div2 Gr D Conduit Questions

Thanks Bob for your prompt response. It is a really nice informative site.

NEMA 7 Junction box as I mentioned in my original posting has HOA, start-stop switches and pilot lights, they are all rated for explosion proof and UL Labeled. In addition, inside the junction box, there are some terminal strips for field devices such as motors and pressure switches located in the same Class 1 Div 2 gr D location. From this junction box, wiring goes to the main panel located in NEMA 12 area (non hazardous area). Do we still need all the conduit entry points of the junction box sealed? Also advise whether we need to seal any of the form 7 conduit fittings located at class 1 Div 2 gr d D area.


Thanks

EK