Page 1 of 2 12 LastLast
Results 1 to 10 of 12

Thread: Arc flash PPE while not working

  1. #1
    Join Date
    Jan 2018
    Location
    TX
    Posts
    2

    Arc flash PPE while not working

    Hi all,

    I've been lurking on here for years and have found many good answers... but I've been unable to find one.

    Most of the time when I think of arc flash and arc flash studies, I think of working on energized equipment. A certain energy level requires a certain PPE level while working.

    What about when no one is working, and the equipment is operating under normal conditions. If someone is just walking by and crosses the arc flash boundary, are they required to wear arc flash PPE?

    thanks,
    tc

  2. #2
    Join Date
    Mar 2003
    Location
    New York
    Posts
    1,342
    Need exposure to live components for arch flash; so should be none unless your out in a yard. You would have your ppe on because you are following the rules to enter the yard after you unlocked the gate to get in the yard.

  3. #3
    Join Date
    Feb 2005
    Location
    Charlotte, NC
    Posts
    6,794
    Quote Originally Posted by sameguy View Post
    Need exposure to live components for arch flash; .
    Not true, 99% of the equipment enclosures out there is not designed to contain an arc flash.

  4. #4
    Join Date
    Feb 2005
    Location
    Charlotte, NC
    Posts
    6,794
    Quote Originally Posted by tcrews17 View Post
    Hi all,

    I've been lurking on here for years and have found many good answers... but I've been unable to find one.

    Most of the time when I think of arc flash and arc flash studies, I think of working on energized equipment. A certain energy level requires a certain PPE level while working.

    What about when no one is working, and the equipment is operating under normal conditions. If someone is just walking by and crosses the arc flash boundary, are they required to wear arc flash PPE?

    thanks,
    tc
    Only when you are interacting with the equipment. That being said, I have a customer that had an employee severely injured from an arc flash from a MCC that he was just walking by, wrong place, wrong time.

  5. #5
    Join Date
    Jan 2018
    Location
    TX
    Posts
    2
    That's what I was thinking as well. Guess the wrong place, wrong time scenario is where I was getting hung up and couldn't find a clear answer in 70E or elsewhere. Thanks for the feedback

  6. #6
    Join Date
    Mar 2003
    Location
    New York
    Posts
    1,342
    Quote Originally Posted by zog View Post
    Not true, 99% of the equipment enclosures out there is not designed to contain an arc flash.
    Zog , I was replying to just walking by, not working on equipment and the need to wear ppe as per the op stated question as I understood it.

  7. #7
    Join Date
    Mar 2016
    Location
    Reston, VA
    Posts
    62

    Arc flash PPE while not working

    It’s true that 70E only requires the PPE when the equipment isn’t in a normal operating state, buttoned up and all. Some companies go further, recognizing that most gear isn’t arc resistant.

    I met a guy that had a switch blow up on him while he was closing it. He alway suits up for operation.

    A lot of companies buy remote operators for the same reason.


    Sent from my iPhone using Tapatalk

  8. #8
    Join Date
    Dec 2012
    Location
    Placerville, CA, USA
    Posts
    19,647
    Quote Originally Posted by gray.one View Post
    It’s true that 70E only requires the PPE when the equipment isn’t in a normal operating state, buttoned up and all. Some companies go further, recognizing that most gear isn’t arc resistant.

    I met a guy that had a switch blow up on him while he was closing it. He alway suits up for operation.

    A lot of companies buy remote operators for the same reason.


    Sent from my iPhone using Tapatalk
    Arc flash calculations are intended to apply to anyone interacting with the equipment, whether they are "working on it" or not. To me that includes operating a switch or breaker if there is any potential of causing an arc flash. This sort of possibility is widely discussed.
    120V snap switch on light circuit: probably not.
    MV service switch, probably!

  9. #9
    Join Date
    Jul 2006
    Location
    San Francisco Bay Area, CA, USA
    Posts
    8,122
    The key concept is "interacting" with the equipment. That includes operating circuit breakers through the door. But the NFPA and OSHA is concerned with workers WORKING on the gear for the most part.

    It's true that people CAN be hurt in an event, even with the doors closed, just by being there, but the risk is considered too low to be made mandatory. Hence the concept of "Arc Resistant" equipment, designed to contain the force of an arc blast or deal with it in a safe manner. Some people want AR gear because the gear is located in areas where people are frequently nearby. The classic is along a factory wall that is used as a passageway.

    This video shows what can happen even with doors closed on a low voltage MCC that is not Arc Resistant. Most of it shows the operator sniffing, looking etc. trying to figure out where the smell is coming from, he even rolls up the door to check if it's coming from outside. The flash happens at about 1:49 if you don't want to wait.
    Last edited by Jraef; 01-10-18 at 09:49 PM.
    __________________________________________________ ____________________________
    Many people are shocked when they discover I am not a good electrician...

  10. #10
    Join Date
    Jul 2006
    Location
    San Francisco Bay Area, CA, USA
    Posts
    8,122
    This one gets right into it. Notice that although some doors are open, the test dummy is in front of the CLOSED doors and the arc flash happens in the gear lineup, but even though there are open doors elsewhere, the blast pressure is so great that it blows the doors off in the CLOSED part.
    __________________________________________________ ____________________________
    Many people are shocked when they discover I am not a good electrician...

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •