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Thread: No Arc Flash label on control panel - What PPE is required.

  1. #1
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    No Arc Flash label on control panel - What PPE is required.

    I support several manufacturing plants in my organization. We are diligently working on our Arc Flash policy. If a control panel does NOT have an AF label on it, what PPE should our people suit up to work on it hot? For the most part our plants are under 2000 KVA at 480 vac. Some are at 240 vac. The calorie level at most power distribution panel is below 15 calories but we have not done the studies down to every Control panel. We have very few motors over 25 HP so the regen contribution from the motor should not be significant.

    If no AF label on the Control Panel, then what PPE is required to work on it hot?

    What about panels that would not require a label because they are 120 vac or 24 DC operator stations that have push button or a operator screen?

  2. #2
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    Quote Originally Posted by Dan Kissel View Post
    If a control panel does NOT have an AF label on it, what PPE should our people suit up to work on it hot?

    If no AF label on the Control Panel, then what PPE is required to work on it hot?

    But we have not done the arc flash studies down to every Control panel.
    Carry out the arc flash study on the control panel to determine whether AF label is required or not.
    Quote Originally Posted by Dan Kissel View Post
    What about panels that would not require a label because they are 120 vac or 24 DC operator stations that have push button or a operator screen?
    If the operators are properly trained personnel, no PPE may be required, if so decided by your company policy.

  3. #3
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    Quote Originally Posted by Sahib View Post
    Carry out the arc flash study on the control panel to determine whether AF label is required or not.

    If the operators are properly trained personnel, no PPE may be required, if so decided by your company policy.
    First, doing a study does not determine if a AF label is needed or not. What determines if a label is needed is NFPA 70E-2015 130.5(D) which in a nutshell says if the equipment is required to be examined, adjusted, serviced or maintained while energized shall be labeled. There are also requirements about what a label needs to contain.

    Second, being properly trained does not mean no PPE is required. It seems absurd that there would be a company policy that states that if you are properly trained no PPE is needed.

    Now back to the OP's question. Stating the transformer kVA and voltage levels implies that one is equating incident energy levels to txf size and voltage. While there are some areas that are exempt from analysis per IEEE 1584-2002, in many cases systems with larger transformers will, overall, have lower incident energies than ones will smaller transformers. This is due to the larger fault, hence arcing currents, will be in the instantaneous trip regions of the protective device.

    If you are using the tables in NFPA 70E, then you need to adhere to the parameters for the task chosen which would be fault current level and clearing times. If those are not known at the control panel you are working on, you can't use the tables. The other limitation on the tables is that if a specific task that is being done is not in the tables, then you cannot use the tables.

    Another known weakness of the tables is that one could be wearing too much PPE or not enough PPE for the task. I seem to remember a study done that concluded the tables gave one a 50% chance of having the correct PPE on. The most certain way to protect your employees is to have a study done.

    For 120Vac, this is single phase and is considered exempt but personnel should still be wearing non melting clothing and protection from shock.

    Same for 24Vdc. Not sure what a pushbutton or touchscreen has to do with wearing PPE. Should be none required there.

  4. #4
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    Thanks wbdvt for clearing my misconceptions also.

  5. #5
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    One minor issue with the above. NFPA 70E is not codified in most jurisdictions. OSHA requires any employer to have a plan, and strongly SUGGESTS that it look like 70E, but nobody will be reading 70E and writing out violations.

    However, the NEC (NFPA 70, no E) is law in almost every jurisdiction in the US, and 110.16 does indeed REQUIRE arc flash labeling.

    So Dan Kissel, yes your employers are required to label every panel with electrical equipment that someone may open (other than limited energy equipment like alarm, BMS or telecom) with arc flash information. Some people even extend that to junction boxes, but I don't take it that far if they are not easily accessible. If you have come across a control panel that doesn't have it, you are required to do the necessary study and apply the label. Using 70E as your guide is the best way to get there in most people's opinion.
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  6. #6
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    My question revolves around the unknown. In the future we will include the control panels in the AF study but right now they are NOT labeled. We literally have 2000 control panels in the our organization.

    When a maintenance person comes up to a panel without a label, he doesn't KNOW what is in the panel. It may just be an 120 vac operator screen or it may have some motor starters in it.

    Without a label - how does a person know what PPE to wear?

    PS I did not suggest the a qualified person did not need to wear PPE.

  7. #7
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    Quote Originally Posted by Dan Kissel View Post
    PS I did not suggest the a qualified person did not need to wear PPE.
    No, Sahib did that.

    mobile

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    Quote Originally Posted by GoldDigger View Post
    No, Sahib did that.

    mobile
    I want to submit I was refering to the OP's 120V AC and 24V DC installations only where no PPE requirements exist for qualified operators who are supposed to take necessary precautions while working and his company is at liberty to do otherwise in this case.

  9. #9
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    With or without labels, a qualified person should be able to identify the type of equipment they are about to work on and general equipment information. A qualified person should also be able to reasonably estimate the hazards (using the tables in 70E as a starting point, as an example) based on voltage labels or other information about the equipment (manuals, etc).

    If the person cannot do these tasks for this equipment, maybe this person should not be considered a qualified person for this equipment/work, and should not proceed with the work.

  10. #10
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    Quote Originally Posted by GonzaloGomez View Post
    ....

    If the person cannot do these tasks for this equipment, maybe this person should not be considered a qualified person for this equipment/work, and should not proceed with the work.
    Din ding ding!

    I think this is an important issue. Remember, you are primarilly required by OSHA to have an electrical safety program for your workers. In that program, the definition of "qualified person" needs to be defined, and as GG pointed out, that really SHOULD include the ability to identify ALL sources of energy entering that panel, LONG BEFORE they consider opening it. If they can't do that, they should not be allowed to open it.

    If they CAN do that, then they also SHOULD be able to determine the arc flash risk, labeled or not. And if that can't be done, then the ONLY safe bet is to assume the worst and suit up!
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