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PPE - Operating Breakers and Bolt-Loc Switches ?

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    PPE - Operating Breakers and Bolt-Loc Switches ?

    We have 4 main 480 services coming into our plant . These range from 4000 amp to 1600 amp . We have bolt-loc switches and molded case SQ D circuit breakers on them . They all have Incident energy level of ( 173 cal/cm at working distance of 1 ft 6 in ) . The PPE level - site-specific says " PROHIBITED " . ( Arc Flash Boundary is 31 ft 2 in ) . I use the PPE we have which is rated 25 Cal's when opening or closing a breaker or switch . Is PPE required to operate a breaker or switch ? If it says "PROHIBITED " is this saying that we must use a remote switch actuator ?

    #2
    Originally posted by Davebones View Post
    We have 4 main 480 services coming into our plant . These range from 4000 amp to 1600 amp . We have bolt-loc switches and molded case SQ D circuit breakers on them . They all have Incident energy level of ( 173 cal/cm at working distance of 1 ft 6 in ) . The PPE level - site-specific says " PROHIBITED " . ( Arc Flash Boundary is 31 ft 2 in ) . I use the PPE we have which is rated 25 Cal's when opening or closing a breaker or switch . Is PPE required to operate a breaker or switch ? If it says "PROHIBITED " is this saying that we must use a remote switch actuator ?
    The term Prohibited is not in NFPA70E. Many, if not most, companies have chosen to prohibit 'work' on equipment >40 cal/cm^2, per their Electrical Safe Work Practices program.

    Before I go any further.

    How often have your bolted pressure switches been operated, daily, yearly, never?
    How often are your switches been maintained, cleaned and lubricated? I think manufacturers recommend every 5 yrs.
    Just because you can, doesn't mean you should.

    Comment


      #3
      Normal Condition

      Davebones,
      As long as the equipment is in normal condition it can be operated without PPE based on table 130.5(C).
      The Normal definition includes properly maintained, which is where much equipment falls short of being Normal. Most electrical testing companies that I've dealt with put a dated sticker on the gear after performing maintenance.

      Comment


        #4
        The incident energy levels and approach boundaries apply to EXPOSED conductive elements. Operating with the doors closed, although still risky for equipment that is NOT rated as Arc Resistant (but properly maintained as mentioned above), should not be assigned the same risk level. What you are seeing is likely a “lazy man’s” risk assessment technique. CYA by forbidding any interaction.

        In my opinion this attitude is actually leading to MORE risk because people tend to ignore equipment they are afraid to use. As someone put it to me yesterday when discussing this, “Our switchgear is basically a fuse now. We can’t go near it, we can’t shut it down or test it, so the only time we can inspect, maintain or repair it is after something blows up.”
        __________________________________________________ ____________________________
        Many people are shocked when they discover I am not a good electrician...

        I'm in California, ergo I am still stuck on the 2014 NEC... We'll get around to the 2017 code in around 2021.

        Comment


          #5
          We've had the switchgear cleaned and tested roughly every 5 years on . It's in a air conditioned environment . I understood that as long as you have maintained it you ( 70E ) said you can operate it . I choose to use the PPE as a extra precaution . I asked the question as with some of the previous posts I've seen it can get confusing about PPE and operating a switch or a breaker . The sticker " PROHIBITED " was put on it after we had the arc flash study done .

          Comment


            #6
            Originally posted by Davebones View Post
            We've had the switchgear cleaned and tested roughly every 5 years on . It's in a air conditioned environment . I understood that as long as you have maintained it you ( 70E ) said you can operate it . I choose to use the PPE as a extra precaution . I asked the question as with some of the previous posts I've seen it can get confusing about PPE and operating a switch or a breaker . The sticker " PROHIBITED " was put on it after we had the arc flash study done .
            Then you technically don't need PPE per 70E with the doors closed for normal operations. But resetting it after a fault for example would not be normal so PPE should be worn (Or remote operators)

            Comment


              #7
              With such a high IE, I am curious to know if the utility actual available fault current was used or was it an infinite bus fault current at the transformer secondaries?

              If modeled with utility actual available fault currents and utilizing the utility protective device on the primary side, your values may be lower.

              Comment


                #8
                The electrical engineer contacted the utility and they did the study with what the utility said was the available fault current .

                Comment


                  #9
                  Originally posted by Davebones View Post
                  The electrical engineer contacted the utility and they did the study with what the utility said was the available fault current .
                  That could be the issue. As an engineer that has done many studies, the first time I request the available fault current, a customer service person provides me with the infinite bus fault current based on installed transformer size. It sometimes takes some effort to get the right info.

                  I also will model from the utility's riser fuse. This way the actual incident energy is known at the service entrance equipment as credit can be taken for the riser fuse protection and an arbitrary cutoff time of 2 seconds is not used.

                  That result seems extremely high.

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