No More Hazard Risk Category 0 – What to Wear with Energy Below 1.2 cal/cm²

  • Post comments:4 Comments
No More Hazard Risk Category 0 – What to Wear with Energy Below 1.2 cal/cm²

Q: Now that  the 2015 NFPA 70E has eliminated Category 0, I am confused on exactly what 70E requires workers to wear when the incident energy is below 1.2 calories.

Long sleeve natural fiber shirt and pants (cotton) seems like a good solution except cotton does not have an Arc Rating, so 70E says it’s not PPE .

Also, some literature suggests that we need a face shield in addition to safety glasses.  (???)  Any help you can give would be appreciated .

A: NFPA 70E now requires no PPE under 1.2 cal/cm² BUT the idea of natural fiber clothing is still in the standard and e-Hazard considers it a best practice for all three phase equipment.

When wearing AR PPE performing electrical tasks, melting garments are still prohibited even in under layers 130.7(C)(9) but may not be used if the breakopen level of the garment is exceeded 130.7(C)(9)(a).  The prohibition of melting fibers “unless arc rated in a blend” is still in effect:

130.7 (C)(9)(c) “Underlayers. Meltable fibers such as acetate, nylon, polyester, polypropylene, and spandex shall not be permitted in fabric underlayers (underwear) next to the skin.”

When you have completed an arc flash study Table H.3(b) recommends in the informative annex to use non-melting (in accordance with ASTM F1506) or untreated natural fiber [though ASTM F1506 doesn’t really have any way to measure this we recommend confirming the materials are 100% natural fiber or expose to a 500F oven test]. We still recommend AR daily wear is best for electricians, and always wear safety glasses and a leather glove or an arc rated glove and turn the head away when operating any three phase electrical equipment if the incident energy is predicted to be less than 1.2 cal/cm2 and it is properly installed, maintained with no evidence of impending or historical failure.

Do a hazard assessment and a risk assessment.  If equipment is poorly maintained or has any sign of impending failure or has a high incident energy which could ignite clothing, use good judgment by using AR PPE.

Remember, the company can require more than the minimum, and if you have calculations, the tables and the HRC/CAT/ARC levels do not apply.  If there are exposed energized parts in the work workers are doing, AR gear is always required.  So the idea of HRC 0 is alive and well in the standard but there is a little more freedom in not requiring it for operators of low voltage equipment <300V which poses and extremely low risk of arc flash.  We recommend this use ONLY in single phase lighting systems like light switches and control switches <300V.  Other exceptions may be built on the basis of your arc flash study, equipment design and maintenance level and risk assessment.

There are limited instances when <300V (208V 3P is an example) could pose an arc flash hazard when the fault current and clearing time are high, these should be assessed by a qualified engineer. IEEE 1584 should have better guidance by 2017.

Have a question about electrical safety and standards? Ask us here on our forum!

Hugh Hoagland

does research and testing of PPE exposed to electrical arcs and is an arc flash expert. Hugh is a Sr. Consultant at ArcWear and Sr. Partner at e-Hazard. Read more about Hugh.

This Post Has 4 Comments

  1. Avatar
    Chad Goff

    We are in the process of changing all our Arc Flash stickers to the new format. The problem we are having is what do we list for correct PPE if the FR rating is .42 or .18. I read in one of your comments that 1.2 was the magic number as to whether we need to wear PPE or not. Where is this stated or eluded to in the NFPA 70E? So according to that statement if the FR rating is below 1.2 we could write “no PPE required.” If the rating is above 1.2 we could state leather gloves, etc. Then i get even more confused when i look at the tables and it states that we need a arc flash shield when the rating is above 1.2 cal. Then to top it all off, i get told that according to NFPA 70E you either have to have the cal rating or the Category #, you can not have both. Little frustrating when you feel you have it all figured out and then you stumble upon something that contradicts what you felt you had figured out. Please help!

    1. Hugh Hoagland
      Hugh Hoagland

      Many purists don’t want you to use a CAT or ARC (Arc Rated Category) when you make labels but this is not really an issue. Use “Annex H Table H.3(b) Guidance on Selection of Arc-Rated Clothing and Other PPE for Use When Incident Energy Exposure Is Determined” You can set your own levels at the same numbers as the CAT/ARC numbers (formerly HRC) but you are NOT bound by it.
      If you have less than 1.2 there is NO PPE required for the distance you calculated but there may be PPE for a closer distance. We recommend that electricians use their AR PPE and that operators for low level equipment use an AR glove or a leather glove. If the energy is closer to 1.2 cal/cm2, consider using an AR sleeve or something so that all the parts of the body inside the AFB (Arc Flash Boundary) are properly protected. Let us know if we can assist.

      Hugh Hoagland

      1. Avatar
        Walter Scott Joynt

        I’m looking for direction for updating arc flash labels and for determining what arc flash gear is required for specific situations.

Leave a Reply