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Thread: Understanding Arc Flash rating requirement

  1. #11
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    Quote Originally Posted by jtinge View Post
    My point was that if you had to ask, you probably were not qualified. A qualified person would have the skills and knowledge and the safety training to assess the hazard or lack thereof and determine if PPE was needed.

    For you and iWire, I guess I am not qualified then. Because I can't see how or why one would need PPE specifically to operate the safety switch handle. The safety switch is designed to interrupt the current available. At what point would PPE not be required if it is for this. Are we going to have to wear PPE to unplug a vacuum cleaner next? And, if so, are you OK with that?


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  2. #12
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    Quote Originally Posted by Strathead View Post
    For you and iWire, I guess I am not qualified then. Because I can't see how or why one would need PPE specifically to operate the safety switch handle. The safety switch is designed to interrupt the current available. At what point would PPE not be required if it is for this. Are we going to have to wear PPE to unplug a vacuum cleaner next? And, if so, are you OK with that?
    You are asking basic questions that a qualified person would be able to answer. The fact that you are asking means as a minimum you need to have some basic electrical safety training.


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  3. #13
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    Quote Originally Posted by jtinge View Post
    You are asking basic questions that a qualified person would be able to answer. The fact that you are asking means as a minimum you need to have some basic electrical safety training.


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    Not a valid answer. If you are going to assert that I need basic electrical training then it is incumbent on you to cite a valid source that shows the energy levels available from a listed safety switch properly closed is enough to warrant PPE and what level of PPE that is. I have a copy of NFPA 70E sitting here waiting for you to cite the section. I can also refer to my OSHA 30 training study material that should have qualified me to answer this basic question, but I guess I missed that part. Yes that last is sarcastic, but if I am wrong I do actually want to know, but just because someone said so isn't good enough.


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  4. #14
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    If you look at what I said, I said as a minimum you need electrical safety training. This is called out in the definition of qualified person.


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  5. #15
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    Quote Originally Posted by Strathead View Post
    For you and iWire, I guess I am not qualified then. Because I can't see how or why one would need PPE specifically to operate the safety switch handle. The safety switch is designed to interrupt the current available. At what point would PPE not be required if it is for this. Are we going to have to wear PPE to unplug a vacuum cleaner next? And, if so, are you OK with that?
    Quote Originally Posted by MikeChaco View Post
    Hello, my name is Mike and I am a Maintenance Tech. I AM NOT AN ELECTRICIAN.

    I work on large pumps and motors. They are 1200HP 4160v. We had all of our switch gear rated and labeled, but I would like some clarification.
    I have gotten conflicting info about our Arc Flash ratings.

    I am trying to find out what PPE is required to operate the disconnect for the attached rated equipment.

    Please let me know if more information is required.
    Thank you
    Returning to the OPs question, there are basically 4 items to answer if PPE is required for a task. See NFPA 70E-2015 Table 130.7(C)(15)(A)(a) but in a nutshell it says that arc flash ppe is not required for normal operation of a circuit breaker or switch if:
    1. The equipment is properly installed
    2. The equipment is properly maintained
    3. All equipment doors are closed and latched
    4. There is no evidence of impending failure

  6. #16
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    Quote Originally Posted by Saturn_Europa View Post

    What version of the NEC 70E is your employer using? We still use the 2012 version which is tasked base.
    NFPA 70E is a national consensus safety standard and comes into effect when is issued, unlike NFPA 70 (NEC) that gets "accepted" by the AHJ. So 70E 2015 came into effect August 2014.

    The idea is that a safer way to do things has been determined so it should be implemented upon issuance of the standard.

  7. #17
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    Quote Originally Posted by wbdvt View Post
    Returning to the OPs question, there are basically 4 items to answer if PPE is required for a task. See NFPA 70E-2015 Table 130.7(C)(15)(A)(a) but in a nutshell it says that arc flash ppe is not required for normal operation of a circuit breaker or switch if:
    1. The equipment is properly installed
    2. The equipment is properly maintained
    3. All equipment doors are closed and latched
    4. There is no evidence of impending failure
    That is what I was looking for. Thank you.


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  8. #18
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    Quote Originally Posted by Strathead View Post
    For you and iWire, I guess I am not qualified then. Because I can't see how or why one would need PPE specifically to operate the safety switch handle. The safety switch is designed to interrupt the current available.

    This is a MV switch, let's not call it a "safety switch". And no they are generally not designed to interrupt the fault current available and some are not even designed to be operated under any load at all which is why you often see them with key interlocks. So per item #1 of a qualified person you have demonstrated a lack of knowledge of the construction and operation of this equipment.

    As far as the PPE requirements (per 2012) operating a MV switch with the doors closed is still HRC 2

  9. #19
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    Quote Originally Posted by Strathead View Post
    Not a valid answer. If you are going to assert that I need basic electrical training then it is incumbent on you to cite a valid source that shows the energy levels available from a listed safety switch properly closed is enough to warrant PPE and what level of PPE that is. I have a copy of NFPA 70E sitting here waiting for you to cite the section. I can also refer to my OSHA 30 training study material that should have qualified me to answer this basic question, but I guess I missed that part. Yes that last is sarcastic, but if I am wrong I do actually want to know, but just because someone said so isn't good enough.
    Besides what other people have said I will ask you this.

    When you turn off the switch how do you do the next required step which is verifying the power is off?

    You are required to wear PPE for that step.

  10. #20
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    Thankyou for the replies.

    The image of the Arc rating label did not get uploaded.

    I am doingvarious maintenance procedures, including adjusting packings but that isdone with pump running.

    My issue is I have been told 2 different things from ourelectricians. 1 says hazard is only when cover is off, I asked anelectrical engineer and he agreed. The other says a Cat 2, 25cal suit isneeded to throw the disconnect with door closed. I read NFPA 70e Table 130.7to require Cat 2. For Metal Clad switch gear 1kV and above.

    Our labels do not say with cover on or off. To me that should mean asconditions are currently.

    My goal here is to start an Arc Flash PPE program. I am attempting to have my company supply, or assist in the cost, of Arc Flash clothing. We work in buildings that are full of equipment. Just being in the building makes us in the boundaries.

    I am not trying to rewire cabinets here, just trying to understand these labels correctly. I feel throwing a disconnect puts me in harms way, and I am trying to validate or dismiss these concerns.


    One of the labels on our gear reads as follows;

    QUALIFIED WORKERS ONLY
    PPE REQUIRED
    438 inch Flash Hazard Boundary
    13.6 cal/cm2 Flash Hazard at 36 inches

    Category 3
    FR Shirt & Pants with FR Coverall with combined AR of at least 25, Hardhat, Hearing Protection, Safety Glasses, Flash Suit Hood, Arc-rated Gloves & leather work shoes

    4160 VAC Shock Hazard when cover is removed
    1 Class Glove with Leather Protectors
    60 inch Limited Approach (Fixed Circuit)
    26 inch Restricted Approach
    7 inch Prohibited Approach


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