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split bus panel PV interconnection rules

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    split bus panel PV interconnection rules

    I am looking for guidance/reference on a pv interconnection to split bus panel at a residential installation (I understand they are no longer permitted but were used at one time). They were allowed under art 230 and the six handle rule.

    #2
    What guidance is needed? They are basically two panels in one. Apply the rules for whichever you want to connect to.

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      #3
      I'll add: these can suck.

      I saw one once that was a 200A service. We needed to install a 7.6kW inverter which would normally be fine. But the service panel was split bus with two 100A sections with 100A main breakers. I said 'either they upgrade that or we charge them the extra for two 3.8kW inverters.' The project ended up not going forward.

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        #4
        Originally posted by jaggedben View Post
        I'll add: these can suck.

        .
        Oh i dunno....i replaced one cuz the HI report claimed the 'panel had no main brkr'....
        ~RJ~

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          #5
          Originally posted by romex jockey View Post
          Oh i dunno....i replaced one cuz the HI report claimed the 'panel had no main brkr'....
          ~RJ~
          Did he know that MLO panels are perfectly legal as MDP's?

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            #6
            Yes.....but the HO would hear nothing of it.....HI's having evolved to sit at the right hand of God and all.....~RJ~

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              #7
              Guess we should have told that customer to get a home inspection.

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                #8
                Originally posted by jaggedben View Post
                What guidance is needed? They are basically two panels in one. Apply the rules for whichever you want to connect to.
                I apologize for my unfamiliarity with this type of panel but they are rare in my area and I don't know much about them. I am not the installer or AHJ, but doing a third party certification of the PV system which includes the interconnection.
                I am unsure if there any rules that apply to the bus on the supply side of the connection. Do the breakers (read: disconnects?) need to have the same interrupt rating that a mocpd would have? Am I missing anything regarding the bus bar loading? My first criteria would be to cite 705.12(A) that the ratings of the sum of all the supply side overcurrent devices not exceed the rating of the service (in this case the bus). Just trying to learn and I appreciate any insight the panel can offer.

                Comment


                  #9
                  Originally posted by jsherwin View Post
                  I apologize for my unfamiliarity with this type of panel but they are rare in my area and I don't know much about them. I am not the installer or AHJ, but doing a third party certification of the PV system which includes the interconnection.
                  I am unsure if there any rules that apply to the bus on the supply side of the connection. Do the breakers (read: disconnects?) need to have the same interrupt rating that a mocpd would have? Am I missing anything regarding the bus bar loading? My first criteria would be to cite 705.12(A) that the ratings of the sum of all the supply side overcurrent devices not exceed the rating of the service (in this case the bus). Just trying to learn and I appreciate any insight the panel can offer.
                  There's nothing different on the supply side from a normal panel.

                  Comment


                    #10
                    Some split bus panels have one bus that is for lighting and other small loads, and this bus is fed from a breaker on a bus connected to the service. As mentioned above the bus connected to service can be treated like any main buss. But a "lighting" bus should not be used for backfeeding photovoltaic power.

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                      #11
                      Originally posted by synchro View Post
                      Some split bus panels have one bus that is for lighting and other small loads, and this bus is fed from a breaker on a bus connected to the service. As mentioned above the bus connected to service can be treated like any main buss. But a "lighting" bus should not be used for backfeeding photovoltaic power.
                      Why not? It's just an embedded sunbpanel. As long as you conform to 705.12 on both buses, I don't see why you couldn't connect to it.

                      Comment


                        #12
                        Originally posted by jsherwin View Post
                        I apologize for my unfamiliarity with this type of panel but they are rare in my area and I don't know much about them. I am not the installer or AHJ, but doing a third party certification of the PV system which includes the interconnection.
                        I am unsure if there any rules that apply to the bus on the supply side of the connection. Do the breakers (read: disconnects?) need to have the same interrupt rating that a mocpd would have? Am I missing anything regarding the bus bar loading? My first criteria would be to cite 705.12(A) that the ratings of the sum of all the supply side overcurrent devices not exceed the rating of the service (in this case the bus). Just trying to learn and I appreciate any insight the panel can offer.
                        It might be more useful to share a picture or diagram of the panel and interconnection. Otherwise we're just speculating about what might be relevant. As mentioned, there are no special rules so it's a matter of understanding how to apply the rules to an unusual situation.

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                          #13
                          Originally posted by ggunn View Post
                          Why not? It's just an embedded sunbpanel. As long as you conform to 705.12 on both buses, I don't see why you couldn't connect to it.
                          I agree.

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                            #14
                            Reposted below with quote added.
                            Last edited by synchro; 07-19-19, 02:59 PM.

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                              #15
                              Originally posted by ggunn View Post
                              Why not? It's just an embedded sunbpanel. As long as you conform to 705.12 on both buses, I don't see why you couldn't connect to it.
                              It could be done, but then it's very likely you'd have to give up one of the 2-pole breaker locations on the main bus anyway in order to meet the maximum of 6 disconnects grouped in one location requirement. Unless the AHJ will allow otherwise.

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