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    #31
    Do we know if there is any exceptions being added to deal with things that were compliant when first installed? That would help some with variations on local level on how to deal with existing, unless the intent of the CMP is to eliminate these altogether.

    There are still a lot of split bus panels still out there.

    Other than to better coordinate with worker safety rules (harder to have a completely de-energized panelboard to work on, yet not impossible) I don't see a great reason for this rule, not sure why the old split bus was even eliminated, other than the ignorant abusing rules they didn't know about.
    I live for today, I'm just a day behind.

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      #32
      Originally posted by electrofelon View Post
      If it's too late for NEC 2020, I would say try to talk to your state code people who are in charge if adopting/amending the NEC. This is what I plan to do in WA.
      Last cycle, I was chair of the committee that developed the Seattle amendments to the NEC. I expect to take on the same role this cycle. I will make sure this issue is carefully considered.

      I am not sure when the state of Washington with take up the 2020 NEC. Nor could I find out (in the few minutes I was able to spend this morning) who the committee members are.

      Charles E. Beck, P.E., Seattle
      Comments based on 2017 NEC unless otherwise noted.

      Comment


        #33
        Originally posted by charlie b View Post
        Last cycle, I was chair of the committee that developed the Seattle amendments to the NEC. I expect to take on the same role this cycle. I will make sure this issue is carefully considered.

        I am not sure when the state of Washington with take up the 2020 NEC. Nor could I find out (in the few minutes I was able to spend this morning) who the committee members are.

        Thanks Charlie. Ill be in touch, and can work up a formal letter to submit when the time comes.
        Ethan Brush - East West Electric. NY, WA. MA

        "You can't generalize"

        Comment


          #34
          What is the substantiation for this 2020 code change? Were there problems with firefighters disconnecting power or something?
          This seems like nonsense without some context.
          I figured we would adopt international light blue neutrals before something like this happened in 2020 ?
          Comments based on 2017 NEC unless otherwise noted.

          Comment


            #35
            Originally posted by tortuga View Post
            What is the substantiation for this 2020 code change? Were there problems with firefighters disconnecting power or something?
            This seems like nonsense without some context.
            I figured we would adopt international light blue neutrals before something like this happened in 2020 ?
            It is driven by 70E in an attempt to limit incident energy and exposure to line side energized parts.
            Don, Illinois
            (All code citations are 2017 unless otherwise noted)

            Comment


              #36
              Originally posted by jaggedben View Post
              But there are a ton of existing meter/main combo service equipment enclosures in my area that are MLO. Just a ton. Hundreds of thousands if not a million in our service area. Like a 3rd of the service panels in suburban areas, I'd say. Especially subdivisions dating from, oh, about 1970 to 2000.

              Here's a fairly typical example that we're dealing with presently:

              [ATTACH=CONFIG]22855[/ATTACH]
              [ATTACH=CONFIG]22856[/ATTACH]


              (Note the part of the label that specifies the six-handle limit.)

              So in a couple years this panel will be bafflingly no longer compliant.

              The question is, will we still be allowed to do what we're doing on this job, which is to relocate that 40A circuit to a sub we're installing on the opposite side of the wall, into which we're also inserting our solar breaker? Will the AHJ be reasonable and say that the whole MSP is grandfathered? Or will we have to tell the customer that they need to increase the cost of the project by 10-50% to replace this recessed meter/main, and it's for a really stupid reason that wouldn't have existed in any of the decades since their house was built?
              IMHO, The Code only applies to newly installed equipment not existing installations.

              Comment


                #37
                Why must only new equipment comply? Post #25 if its to limit incident energy I would imagine existing equipment to must comply as well due to safety reasons. Something needs to be address in 2020 regarding existing equipment not to be left to individual AHJ. I could forsee lots of fights and headache with contractors why we have to replace existing if code does not address what to do existing.
                Last edited by hhsting; 04-30-19, 06:35 PM.

                Comment


                  #38
                  Originally posted by xformer View Post
                  IMHO, The Code only applies to newly installed equipment not existing installations.
                  1) That's just your opinion. If my company had the money back from every time an inspector had a different opinion than me, we could probably pay someone's yearly salary.

                  2) I'm talking about making changes to service equipment installations that run afoul of this new language. My part of the installation isn't 'existing.'

                  Comment


                    #39
                    Originally posted by don_resqcapt19 View Post
                    It is driven by 70E in an attempt to limit incident energy and exposure to line side energized parts.
                    That was my suspicion all along, They now require line barriers on main terminals - might not completely be compliant to 70E for limiting exposure, but is a step in that direction anyway. Now if you have a main lug only and bus that is always energized - it is more difficult to get that into as limiting of exposure condition as it would be with a single main breaker.

                    Originally posted by xformer View Post
                    IMHO, The Code only applies to newly installed equipment not existing installations.
                    Most places recognize things that were compliant at the time they were installed. The question becomes can you add to this panel that once was compliant but now is not? If NEC does not specifically put in conditions for this, whether it be in main language or as exceptions, I can see there being a mixture of ways of dealing with the existing by AHJ's.
                    I live for today, I'm just a day behind.

                    Comment


                      #40
                      Originally posted by hhsting View Post
                      Why must only new equipment comply? Post #25 if its to limit incident energy I would imagine existing equipment to must comply as well due to safety reasons. Something needs to be address in 2020 regarding existing equipment not to be left to individual AHJ. I could forsee lots of fights and headache with contractors why we have to replace existing if code does not address what to do existing.
                      The NEC is correlating and attempting to harmonize with 70E. In 70E, it is allowed to work on or around energized parts if it is "infeasible" to de-energize. Many would consider a MLO service panel to fall under this allowance due to the fact that the only way to de-energize is to have the utility company shut the entire building down. It sounds like 70E wants to eliminate this type of new installation due to shock hazards and high incident energy levels.

                      Existing installations are just that, existing.
                      [COLOR="indigo"]Marty Schumacher
                      Electrical Inspector, Plans Examiner, Code Instructor[/COLOR]

                      "All men by nature desire to know"[COLOR="indigo"][COLOR="purple"][/COLOR][/COLOR]

                      Comment


                        #41
                        Originally posted by inspector141 View Post
                        ...

                        Existing installations are just that, existing.
                        Seems like people keep missing the point.

                        Suppose I have an existing MLO meter main with one service disconnect, built to accommodate up to six. I want to add a second service disconnect. Does the 2020 code allow this? If not, seems pretty unfair. Now we have all the safety issues involved in replacing a service, when we didn't have that before. Especially for resi services, with non CT meters. Heck, just pull the meter if you need to de-energize. Heck of a lot safer than replacing the service panel, whether it is a trained lineman disconnecting the drop or a risk-taking EC cutting it, like they pretty much make you do in some places.

                        I will start a new thread in proposals forum about this, and post a link when I've done so.
                        Last edited by Little Bill; 05-12-19, 03:35 PM. Reason: Language

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                          #42
                          Originally posted by don_resqcapt19 View Post
                          It is driven by 70E in an attempt to limit incident energy and exposure to line side energized parts.
                          Ahhh then there should be an exception for single phase equipment as there is not even an IEEE guide for that, or at least exempt 240 V and below unless it involves at least one 125 kVA or larger low transformer.
                          Comments based on 2017 NEC unless otherwise noted.

                          Comment


                            #43
                            Originally posted by tortuga View Post
                            Ahhh then there should be an exception for single phase equipment as there is not even an IEEE guide for that, or at least exempt 240 V and below unless it involves at least one 125 kVA or larger low transformer.
                            NFPA70E does not exempt single phase systems from Arc Flash analysis. You just cannot simply use IEEE-1584 as you can with three phase systems.

                            The 125kVA and smaller 'exception' was removed from IEEE-1584 in the 2018. Effectively it was changed to 2,000A of fault current or less.
                            Just because you can, doesn't mean you should.

                            Comment


                              #44
                              Originally posted by jim dungar View Post
                              NFPA70E does not exempt single phase systems from Arc Flash analysis. You just cannot simply use IEEE-1584 as you can with three phase systems.

                              The 125kVA and smaller 'exception' was removed from IEEE-1584 in the 2018. Effectively it was changed to 2,000A of fault current or less.
                              Thats interesting, again I wonder why and if there is an outbreak of single phase accidents or something?
                              I am not on the 1584-2018 yet. I wonder what the Basic Equation formula they published for 120/240V single phase is?
                              Comments based on 2017 NEC unless otherwise noted.

                              Comment


                                #45
                                Originally posted by tortuga View Post
                                Thats interesting, again I wonder why and if there is an outbreak of single phase accidents or something?
                                I am not on the 1584-2018 yet. I wonder what the Basic Equation formula they published for 120/240V single phase is?
                                My guess is the majority of industrial single phase systems are rather low incident energy, more likely to be control circuit systems.

                                But there is a lot of light industrial/light commercial that are supplied with single phase and large enough sources that you may have higher incident energy at least at your service equipment.
                                I live for today, I'm just a day behind.

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