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Thread: Kern County and 705.12(D)

  1. #11
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    Quote Originally Posted by jaggedben View Post
    I'm trying to imagine what equipment you are dealing with where this description makes sense. If it's not capable of supplying multiple of either, then what difference does a comma make? In my experience, if you have a panelboard, then nearly by definition ("automatic overcurrent devices", plural) it is capable of feeding multiple branch circuits or feeders, or both. Unless this debate is about a circuit breaker enclosure or disconnect that is being incorrectly considered to be a panelboard, then my best guess is that I probably agree with the county's point of view about the rules that apply. But note that in the 2014 code the 120% rule (and the others ggunn described for you) only apply to panelboards, so if it isn't a panelboard, then that might be your last good bet at changing their minds. The other possibility might be if the busbars are on the supply side of the service disconnecting means, then the rules also don't apply.

    To be more succint, it's hard to help without knowing the details of the equipment and setup.
    Agreed, and I'll just add that just because a panelboard doesn't supply feeders or branches in a particular application does not mean that it is incapable of doing so. It seems to me that the language is meant to distinguish between panelboards and devices such as enclosed circuit breakers.

  2. #12
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    Quote Originally Posted by ggunn View Post
    Agreed, and I'll just add that just because a panelboard doesn't supply feeders or branches in a particular application does not mean that it is incapable of doing so. It seems to me that the language is meant to distinguish between panelboards and devices such as enclosed circuit breakers.
    I would think that if a panelboard is filled by the incoming utility breaker, the incoming alternate source breaker, and the outgoing feeder breaker, then it would be exempt from the 705.12(D) subitem requirements. For example, I have a meter main on my house with room for just one main breaker and two additional double pole breakers.

    Cheers, Wayne

  3. #13
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    Quote Originally Posted by wwhitney View Post
    I would think that if a panelboard is filled by the incoming utility breaker, the incoming alternate source breaker, and the outgoing feeder breaker, then it would be exempt from the 705.12(D) subitem requirements. For example, I have a meter main on my house with room for just one main breaker and two additional double pole breakers.
    I don't agree. First, it is feeding both a feeder and a branch circuit, which is the 'or both' in the language. This argument over commas and plurals is one I would never make to an AHJ with a serious expectation of winning the point. But on a broader level, it is a panelboard with busbars that are are listed to a certain standard. Whatever safety issues justify rules that apply to those, those issues are still in play. The issue is knowing that the thermal output of both the utility and inverter breaker together won't damage the busbar. If anything, having a smaller busbar with less room for thermal dissipation makes the problem worse. If any busbar should be exempted (to be clear, none are) it would be the one that's 3ft long in a 42 circuit panel.

  4. #14
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    Quote Originally Posted by jaggedben View Post
    I don't agree. First, it is feeding both a feeder and a branch circuit, which is the 'or both' in the language.
    Sorry, I don't see that. In my example, in the language of 705.12(D), the panel is "fed" by the utility and the alternate source and is "supplying" just one feeder, and there is no room for another breaker to supply another feeder or branch circuit. With all loads supplied through one breaker, how can the bus ever be overloaded?

    Cheers, Wayne

  5. #15
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    Quote Originally Posted by jaggedben View Post

    To be more succint, it's hard to help without knowing the details of the equipment and setup.

    Yeah, I should have described the equipment in the original post.

    We have an 800A meter-main with only one 800A service disconnect, and no bus for additional disconnects or branch circuits. The service disconnect feeds directly to an 800A breaker (Pump Breaker) in an adjacent panel with no bus or room for any additional breakers. There is a single 800A load after the pump breaker (it is a large ag pump). We are attempting to tap on the load side conductors between the service disconnect & pump breaker. A line side tap/connection is not possible in this panel. We are backfeeding close to 800A of PV, so complying with the 120% rule is out of the question. This is an aggregate NEM array, which is why the PV is so large.


    To further clarify the issue we are having: We are interpreting 705.12(D) as though our distribution equipment is not capable of supplying multiple branch circuits, or multiple feeders (it only supplies 1 feeder to the pump breaker). This would exempt us from the 120% rule and the rest of (D)(1) through (D)(6).

    The AHJ's interpretation is that "multiple branch circuits or feeders" means multiple branch circuits, and that multiple does not apply to feeders... so feeding a single breaker would not exempt (D)(1) through (D)(6).


    My interpretation: …and where this distribution equipment is capable of supplying
    1.multiple
    a. branch circuits
    b. or feeders,
    2. or both,

    Kern County's interpretation: …and where this distribution equipment is capable of supplying
    1. multiple branch circuits
    2. or feeders, (not multiple)
    3. or both,

    ​If the sentence was written with the comma shown in red "...capable of supplying multiple branch circuits, or feeders, or both" then I would agree the AHJ could interpret multiple as not applying to feeders, despite feeder being plural. But it's not, and there is no comma after branch circuits. It is "...capable of supplying multiple branch circuits or feeders, or both".
    Last edited by anndee4444; 07-14-17 at 12:37 PM. Reason: clarification of second panel

  6. #16
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    Quote Originally Posted by anndee4444 View Post
    We have an 800A meter-main with only one 800A service disconnect, and no bus for additional disconnects or branch circuits. The service disconnect feeds directly to an 800A breaker (Pump Breaker) in another panel that is 1' away. There is a single 800A load after the pump breaker (it is a large ag pump). We are attempting to tap on the load side conductors between the service disconnect & pump breaker.
    Seems to me this scenario falls under (2014) 705.12(D)(2)(1), as you are making the inverter output connection at the feeder rather than at the service disconnect.

    Cheers, Wayne

  7. #17
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    Quote Originally Posted by wwhitney View Post
    Seems to me this scenario falls under (2014) 705.12(D)(2)(1), as you are making the inverter output connection at the feeder rather than at the service disconnect.

    Cheers, Wayne

    My interpretation is that we are exempt from the second sentence of 705.12(D), and the only part that applies is the first sentence:
    "The output of a utility-interactive inverter shall be permitted to be connected to the load side of the service disconnecting means of the other source(s) at any distribution equipment on the premises."

    Since the second sentence is not true, then we do not have to "comply with 705.12(D)(1) through (D)(6)", including 705.12(D)(2)(1).

  8. #18
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    Quote Originally Posted by wwhitney View Post
    I would think that if a panelboard is filled by the incoming utility breaker, the incoming alternate source breaker, and the outgoing feeder breaker, then it would be exempt from the 705.12(D) subitem requirements. For example, I have a meter main on my house with room for just one main breaker and two additional double pole breakers.

    Cheers, Wayne
    Yes, but that is a characteristic of the application, not of the piece of gear itself. It's the gear itself that I believe that the code is referring to. It says "...is capable of feeding...", not "....is feeding...". Your point is that the application makes it incapable. The governing AHJ does not agree, apparently.

  9. #19
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    Quote Originally Posted by wwhitney View Post
    Sorry, I don't see that. In my example, in the language of 705.12(D), the panel is "fed" by the utility and the alternate source and is "supplying" just one feeder, and there is no room for another breaker to supply another feeder or branch circuit. With all loads supplied through one breaker, how can the bus ever be overloaded?

    Cheers, Wayne
    I agree. If there is nothing but one correctly sized OCPD at either end of a bus bar or conductor, there is no way that it can ever be overloaded by PV backfeed.

  10. #20
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    Quote Originally Posted by ggunn View Post
    It says "...is capable of feeding...", not "....is feeding...". Your point is that the application makes it incapable. The governing AHJ does not agree, apparently.
    This is a good point... The AHJ is not currently arguing this, but I could see them changing to it, since technically ANYTHING is capable of supplying multiple feeders with enough determination/stupidity (code compliant or not).

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