×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Class 1 Div 1/2 enclosure question

Class 1 Div 1/2 enclosure question

Class 1 Div 1/2 enclosure question

(OP)
i am working on a new design for an electrical termination box for an resistance element heater.  i am using a killark box rated as explosion proof suitable for class 1/ div 1 hazardous areas.  the box has a 2" NPT opening in the back of it & a 3/4" NPT opening on the side for rigid conduit attachment(installed by customer).  the heater will be flange connected to a holding tank. i am welding a 2" pipe nipple to the flange and epoxy potting the tubular heating elements, whil containing all arcing contacts entirely within the killark enclosure. my thinking is that the 2" NPT potted nipple attached to the box is technically a "sealed conduit connection" so that the arcing contacts are located within the enclosure.
would the enclosure now be considered explosion proof & suitable for class 1 div 1 areas? i apologize if the post is unclear, the link below is a sketch of what i am trying to do.  i understand that the entire heater may not be entirely explosion proof due to he possibility of high surface temps, but my concern right now is the just terminal enclosure being rated as explosion proof. all help is greatly appreciated.


http://i644.photobucket.com/albums/uu168/WEC2009/EPENCLOSURE.jpg
 

RE: Class 1 Div 1/2 enclosure question

I think NEC 500.8(D)(1) states that Listed conduit, conduit fittings, or cable fittings shall be used for equipment provided with threaded entries.  Your flanged section with pipe threads does not meet the requirements.

Plus, the piping, flange and epoxy potting are not listed devices.

The cable routing must be in conduit, with the proper seal.

______________________________________________________________________________
This is normally the space where people post something insightful.

RE: Class 1 Div 1/2 enclosure question

Is the heater element UL Listed?

RE: Class 1 Div 1/2 enclosure question

(OP)
some are UL listed, others not. why?

RE: Class 1 Div 1/2 enclosure question

See NEC 500.8 Equipment

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources