×
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

Required Clearance of Live Parts to Grounded Surface inside a NEMA Box

Required Clearance of Live Parts to Grounded Surface inside a NEMA Box

Required Clearance of Live Parts to Grounded Surface inside a NEMA Box

(OP)
We have vendor supplying a NEMA 4 box for Surge Arrestor/Capictor application and our customer stated that the sidewall clerance is small and may not meet required CSA or IEEE code from live parts to grounded surface.  Could you let me know if there is such a requiremetn out there? Especially for clearance inside an electrical cubicle?  If there is not requirement, please specific section (s) of CSA and/or IEEE stating this.   

connection is to be made to the busbar inside the enclosure.  Line voltage is 6.6-6.9 kV.

I understand there is special requirement of exposed live parts relative to building structure/etc.

Anyone help/insight would be greatly appreciated.  

RE: Required Clearance of Live Parts to Grounded Surface inside a NEMA Box

I am not sure of the CSA requirments but the NEC has a table showing minimium clearance of bare live parts.  It can be found in NEC table 490.24.  For 7.2kV indoors the clearance is 5.5 inches phase to phase, and 4 inches phase to ground.  

RE: Required Clearance of Live Parts to Grounded Surface inside a NEMA Box

(OP)
Thanks pwrengrds - that was helpful. Now to see whether CSA has a similar table.  It seems that CSA might be written based on NEC sometimes.  

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