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Thread: Using an E-Stop as a LOTO

  1. #1
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    Using an E-Stop as a LOTO

    I was under the impression that NFPA70E did not recognize an emergency stop i.e. maintain, lockable, etc. as a valid lockout tag out device. When I browse through the internet and I see e-stop devices that can be used as a LOTO thus you can imagine my confusion. Thanks for any clarification.

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    Quote Originally Posted by fraymond View Post
    I was under the impression that NFPA70E did not recognize an emergency stop i.e. maintain, lockable, etc. as a valid lockout tag out device. When I browse through the internet and I see e-stop devices that can be used as a LOTO thus you can imagine my confusion. Thanks for any clarification.
    If it was me or one of my guys I certainly wouldn't consider it as a LOTO device regardless of what any rules or code may say. The E-stop may prevent you from running a machine. It doesn't make it safe to work on electrically.
    Si hoc legere scis nimium eruditionis habes.

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    Back in the 80's we used them for motor disconnects to break the control circuit of the motor starter. Sometime in the early 90's we no longer used them presumably because it was no longer code compliant.
    Rob

    Moderator

    All responses based on the 2014 NEC unless otherwise noted

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    Good thread on the subject.

    http://forums.mikeholt.com/showthread.php?t=67915

    I agree with Don in that thread. An e stop/EPO button does not qualify as a disconnecting means for LOTO.
    "Electricity is really just organized lightning." George Carlin


    Derek

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    Quote Originally Posted by fraymond View Post
    I was under the impression that NFPA70E did not recognize an emergency stop i.e. maintain, lockable, etc. as a valid lockout tag out device. When I browse through the internet and I see e-stop devices that can be used as a LOTO thus you can imagine my confusion. Thanks for any clarification.
    There are newer OSHA regulations that now allow "alternatives" to LO/TO for certain identified "repeated and necessary" tasks, where a full removal of energy would cause undue hardship. The classic example is a pill conveyor at a pharmaceutical production line that jams constantly, requiring someone to reach in and clear it. Powering down completely, locking it out, clearing the jam and calling the electrician to power it back up again every time would be impractical, so part of the ROUTINE operation of the machine, as the operators are TRAINED for, is a simpler Safety Interlock system, often using E-Stop buttons.

    But that is NOT the same as LO/TO from an NFPA 70E standpoint. NFPA 70E is not about safe OPERATIONS, it is about protecting ELECTRICAL workers. So ostensibly, an electrician is not involved in the "routine" operation of a machine, he/she is involved in ABNORMAL situations or maintenance involving electrical components. For the electrician, LO/TO is ALWAYS about removing electrical energy and the potential for it coming on inadvertently. So for ELECTRICAL safety purposes, E-Stops or other control devices are NEVER allowed.
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    Quote Originally Posted by Jraef View Post
    LO/TO is ALWAYS about removing electrical energy and the potential for it coming on inadvertently.
    +1
    an air break, and a padlock means that an inadvertent
    control malfunction isn't a bent piece of equipment, or
    a bent piece of people.

    if i want to work on controls, i can always shut off the
    cabinet disconnect, lift motor wires on the contactors, and
    tinker to my heart's content. nothing spins, no oopsies.
    ~New signature under construction.~
    ~~~~Please excuse the mess.~~~~

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    I'm struggling with the example of the pill conveyor. If LO/TO is for the inadvertent startup of equipment i.e. controls malfunction why would it be safe to use an e-stop or sorts? I also struggle with the comment NFPA 70E is for protecting electrical workers.

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    Quote Originally Posted by fraymond View Post
    I'm struggling with the example of the pill conveyor. If LO/TO is for the inadvertent startup of equipment i.e. controls malfunction why would it be safe to use an e-stop or sorts? I also struggle with the comment NFPA 70E is for protecting electrical workers.
    One possible explanation would be because the manufacturer of the pill making equipment owns the Caribbean condo where the rules making committee vacation.
    At my age, I'm accustomed to restaurants asking me to pay in advance, but now my bank has started sending me their calendar one month at a time.

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    Quote Originally Posted by augie47 View Post
    One possible explanation would be because the manufacturer of the pill making equipment owns the Caribbean condo where the rules making committee vacation.
    Now, now..........
    Si hoc legere scis nimium eruditionis habes.

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    Quote Originally Posted by fraymond View Post
    I'm struggling with the example of the pill conveyor. If LO/TO is for the inadvertent startup of equipment i.e. controls malfunction why would it be safe to use an e-stop or sorts? I also struggle with the comment NFPA 70E is for protecting electrical workers.
    There are numerous ways of applying Machine Safety Systems that protect workers with tested and certified systems allowing routine machine entry for inspection, cleaning, clearing tasks during normal operation. Those systems have checks, cross checks and re-checks, along with established re-start routines that ensure worker safety, WITHOUT having to power down the entire machinery. Although not yet codified here in North America, that is the standard in the rest of the world and because of that, it is already ALLOWABLE by OSHA. At some point those Safety Systems will be codified here as well, just not yet.

    But that is NOT about protecting an ELECTRICAL worker who will have their hands in the ELECTRICAL equipment. For that, you MUST have a means of isolating all electrical energy away from the enclosure being worked on, as well as any potential for Arc Flash blast pressure. So that makes LO/TO for electrical work DIFFERENT from machine safety systems. Yes, if you use electrical LO/TO for any kind of machinery process work it's perfectly legit, just possibly impractical for routine operations.
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