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!

*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

Working distance to non-exposed electrical equipment

Working distance to non-exposed electrical equipment

Working distance to non-exposed electrical equipment

Have an application where personnel generally work/break near fully enclosed 4160V switchgear (AF cat 0) and 480V MCC (AF cat 3).  Standard practice requires normal PPE, clearing area and barricading for any energized work or switching procedures.  

Staff are trying to use the proximity of the electrical gear as a safety justification to push the funding for construction of a new work space.  After a seemingly exhaustive search of standards and codes have found that they address exposed energized equipment, but not the normal operation of enclosed equipment.  

Are there any references, codes, or the like that would address this application apart from the vague note and only 600V or less in the latest NFPA 70E... [130.7(A)]that states: "it is the collective experience of the Technical Committee on Electrical Safety in the Workplace that normal operation of enclosed electrical equipment, operating at 600 volts or less, that has been properly installed and maintained by qualified persons is not likely to expose the employee to an electrical hazard."

For further clarification, temporary or permanent equipment is not stored within the clear working space of the electrical gear.

Looking for resource to support the conclusion that the equipment is inherently safe?

RE: Working distance to non-exposed electrical equipment

Arc-flash is the new kid on the block. Equipment that meets NEC clearances may now require that anyone approaching within limits needs to be protected by arc flash gear rated for the arc-flash energy level.  

"Why not the best?"
Jimmy Carter

RE: Working distance to non-exposed electrical equipment

In your response, you state "may now require..."  Are you aware of any proposed rules on the subject?  

I was previously under the impression that work activities that do not involve the electrical equipment are inherently safe?

RE: Working distance to non-exposed electrical equipment

I'm not sure what "inherently safe" means.  Virtually everyone interprets NFPA 70E to NOT required PPE when passing by enclosed electrical equipement with no exposed live parts and no switching going on.  Many organizations require PPE for switching of 480 V equipment even with the doors closed, but there are many that allow this switching with no PPE.  

In your case, as long as the space is cleared of people before any doors are opened on the 480 V gear, this probably meets the intent of NFPA 70E.  I would advise clearing the area for any switching of 4160 V switchgear.

Keep in mind that NFPA 70E is a consensus standard, and does not carry the force of law as the NEC (where applicable) does.  

Having said that, this work space sounds like a less than ideal situation.  I would not want staff taking breaks directly in front of 4160 V switchgear. It is just not a good practice.

I'm a little suspicious of your Hazard/Risk Category #0 on the 4160 V gear.  Is there a main breaker in this lineup and if so, how does a fault in the main breaker get cleared?   

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! Already a Member? Login


Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close