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Thread: 690 or 705 sections that need changes for the 2020 NEC cycle?

  1. #21
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    Originally Posted by ggunn I would like the NEC to declare one way or the other whether or not an AC disco on a supply side connected PV system needs a neutral to ground bond, with all that entails. Some AHJs say yes, others say no.
    Quote Originally Posted by pv_n00b View Post
    So would I. I’ll see what I can bring up to make it more declarative. I’ll tell you though, I’ve brought this up before and some people seem to think it’s clear that it is not a service entrance so they block adding any wording to that effect.
    It seems clear to me that an AC PV disco is part of the service entrance- I think it is at the "load end" of the service entrance, and it is service equipment.
    It has service conductors or service entrance conductors on the grid side, and PV output conductors on the PV side, and it cuts off the PV from the grid.

    But it could be clearer for sure.
    Service conductors and service entrance conductors are defined in code- I don't see where "service entrance" is used by itself without conductors right after.

    NatGrid says this-
    Service entrance:
    That part of the Customer's wiring from the point of attachment or termination
    of the service lateral or service line to and including the service equipment.

    ^^ That means service entrance = everything from drip loop (when overhead) to breakers or fuses.

    These defs. are 2017 code, Art.100.
    One thought is that the _______ after load end of service conductors might say... "or load end of service entrance conductors"?
    The service entrance conductors are a subset of service conductors, and the former is not always part of the setup.
    I like that Info Note at the bottom
    ---
    Service Equipment.
    The necessary equipment, usually consisting of a circuit breaker(s) or switch(es) and fuse(s) and
    their accessories, connected to the load end of service conductors ______ to a building or other structure, or an otherwise designated
    area, and intended to constitute the main control and cutoff of the supply.

    Service Conductors.
    The conductors from the service point to the service disconnecting means.

    Service Conductors, Overhead. The overhead conductors
    between the service point and the first point of connection
    to the service-entrance conductors
    at the building or other
    structure.

    Service Conductors, Underground. The underground conductors
    between the service point and the fIrst point of connection
    to the service-entrance conductors
    in a terminal box,
    meter, or other enclosure, inside or outside the building wall.
    Informational Note: Where there is no terminal box, meter,
    or other enclosure, the point of connection is considered to
    be the point

    Service-Entrance Conductors, Overhead System.
    The service conductors between the terminals of the service
    equipment
    and a point usually outside the building, clear of
    building walls, where joined by tap or splice to the service
    drop or overhead service conductors
    .

    Service-Entrance Conductors, Underground System.
    The service conductors between the terminals of the service
    equipment
    and the point of connection to the service lateral
    or underground service conductors
    .

    Informational Note: Where service equipment is located
    outside the building walls,there may be no service entrance
    conductors or they may be entirely outside the
    building.

    (my note, as in: a supply side PV system OCPD and j-box, outside...or...a MDP for a house, outside- no service entrance.
    When PV OCPD/j-box are outside and house MDP is inside, it's service entrance conductors to house, service conductors to PV OCPD)

  2. #22
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    Quote Originally Posted by PVfarmer View Post
    It seems clear to me that an AC PV disco is part of the service entrance- I think it is at the "load end" of the service entrance, and it is service equipment.
    It has service conductors or service entrance conductors on the grid side, and PV output conductors on the PV side, and it cuts off the PV from the grid.[big ol' snip]
    Hence my point; many others see it differently.

    Just a tip: when you just cut and paste large blocks of text into a post I doubt many read it. I know I don't.

  3. #23
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    Quote Originally Posted by pv_n00b View Post
    So would I. I’ll see what I can bring up to make it more declarative. I’ll tell you though, I’ve brought this up before and some people seem to think it’s clear that it is not a service entrance so they block adding any wording to that effect.
    Others seem to think it's clear that it IS a service entrance. I don't understand why they would block wording that would make it clear, either way they want it to be. I really don't care which.

  4. #24
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    Quote Originally Posted by ggunn View Post
    the NEC to declare one way or the other whether or not an AC disco on a supply side connected PV system needs a neutral to ground bond,

    Just a tip: when you just cut and paste large blocks of text into a post I doubt many read it. I know I don't.

    Others seem to think it's clear that it IS a service entrance
    I think it does declare that a N-G bond is required, but since you don't care what I have to say, why bother?

    I'm pasting the code being referenced so people don't have to look it up somewhere else.
    If you want to ignore it and not argue, great!

    But you could show this pic to people who think a switch is a "service entrance", and point out that the service entrance goes from the grid side of the overhead drip loop/underground service point to the load side of the service equipment.
    You could also point out that the code does NOT define "service entrance", period.
    It defines service entrance CONDUCTORS, overhead and underground.

    It just seems so glaringly obvious to me that the PV OCPD switch is simply service equipment with service conductors on the grid side and protected PV output conductors on the PV side.

    Edit:Imagine this pic is showing a PV system to grid, and no house loads are involved.
    How could you possibly say the PV switch isn't service equipment?

    Click image for larger version. 

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    Last edited by PVfarmer; 03-29-17 at 11:37 AM.

  5. #25
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    Quote Originally Posted by PVfarmer View Post
    ...
    It just seems so glaringly obvious to me that the PV OCPD switch is simply service equipment with service conductors on the grid side and protected PV output conductors on the PV side.
    ...
    The term service in this context originates from the utility providing electrical energy to a consumer, i.e. the utility provides the "service" and the customer consumes the "service". In the case of a supply-side PV POC, there is no "service".
    I'll never get there. No matter where I go, I'm always here.

  6. #26
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    Quote Originally Posted by PVfarmer View Post
    I think it does declare that a N-G bond is required, but since you don't care what I have to say, why bother?
    I have to say that you've got that right; I really don't care. There is only one AHJ in Texas that I have dealt with so far who requires a N-G bond in the disco, and the NEC is ambiguous on the question. I can see that your interpretation is that it is required, but that is your interpretation, not an explicit statement in the Code, and by my lights your interpretation of the Code sometimes leaves something to be desired.

    Personally, I don't care which way it goes; it's just a pain to find out what an AHJ expects, and some of them have never thought about it.

  7. #27
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    Quote Originally Posted by Smart $ View Post
    The term service in this context originates from the utility providing electrical energy to a consumer, i.e. the utility provides the "service" and the customer consumes the "service". In the case of a supply-side PV POC, there is no "service".
    The service begins where conductors are connected to the POCO's xfmr, and ends at the load side terminals of the service equipment.
    Supply side PV is connected to the service conductors or service entrance conductors which lead to service equipment for utilization loads.

    A- Service conductors and PV output conductors are all part of the premises wiring.

    B- I see what you mean, the NEC "service" definition doesn't mention PV, yet PV and grid are both "delivering electric energy ... to the wiring system of
    the premises". So that strikes me as weird. Nevertheless, the "service connection" in the NatGrid pic, which I would take to mean the same as service, is everything from POCO xfmr terminals to load side terminals of service equipment.
    NatGrid's defintion for service could even include their xfmr...

    Also, the service entrance = things in bold.

    C- A PV system is defined as everything producing power "suitable for connection to a utilization load".
    I think it is connected where the switch is. If somebody opens the switch, the PV is no longer connected to the load (or utility...)

    ===

    A
    Premises Wiring (System). Interior and exterior wiring,
    including power, lighting, control, and signal circuit wiring
    together with all their associated hardware, fittings, and
    wiring devices, both permanently and temporarily installed.
    This includes (a) wiring from the service point or power
    source
    to the outlets or (b) wiring from and including the
    power source to the outlets where there is no service point.
    Such wiring does not include wiring internal to appliances,
    luminaires, motors, controllers, motor control centers,
    and similar equipment.
    Informational Note: Power sources include, but are not
    limited to, interconnected or stand-alone batteries, solar
    photovoltaic systems
    , other distributed generation systems,
    or generators.

    B
    NEC
    Service. The conductors and equipment for delivering electric
    energy from the serving utility to the wiring system of
    the premises served.

    NatGrid
    Service:
    The conductors and equipment for delivering energy from the Company's distribution line
    to the wiring system of the Customer served.

    Service Cable.
    Service Conductors.
    Service Conductors, Overhead.
    Service Conductors, Underground.
    Service Drop.
    ("service entrance" not present)
    Service-Entrance Conductors, Overhead System.
    Service-Entrance Conductors, Underground System.
    Service Equipment.

    Service Lateral.
    Service Point.

    C
    Photovoltaic (PV) System. The total components and subsystem
    that, in combination, convert solar energy into electric
    energy suitable for connection to a utilization load.

  8. #28
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    Quote Originally Posted by ggunn View Post
    I have to say that you've got that right; I really don't care.
    Well the first part is encouraging...

    So what do you think about this diagram?
    Forget about which conductors are called what- just the green parts.
    We're supposed to bond N to G at the first disconnecting means.

    Does the diagram show that correctly? I think so... Yes there are 2 "means", but they are both the first.

    Click image for larger version. 

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  9. #29
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    I simply don't understand how anybody can read this in the context of a PV disco:
    Art. 100
    Accessible, Readily (Readily Accessible). Capable of being
    reached quickly for operation, renewal, or inspections
    without requiring those to whom ready access is requisite
    to actions such as to use tools, to climb over or remove
    obstacles, or to resort to portable ladders, and so forth.


    And then think that emergency equipment *inside* a house is readily accessible to the people who want to use it.

    Here is why it is confusing- when the DC disco is remotely operated by the AC PV disco, it is both ok for the DC to be inside, and the accessibility of the DC switch is irrelevant when you are not operating it directly.

    705.12 says zilch about the (AC) disco being allowed indoors, which is easily fixed by adding one word.

    Check out the link below-
    I'm not sure if y'all are saying the "service OCD" doesn't exist with supply side PV, or that a limiter would = the service OCD, but...
    A limiter is definitely not a switch!

    So again, I think the fact that 705.12 does *not* say indoors is allowed, means that it isn't, so it should say so.

    III. Disconnecting Means
    690.13 Building or Other Structure Supplied by a PhotovoltaicSystem.
    Means shall be provided to disconnect
    all ungrounded dc conductors of a PV system from all other
    conductors in a building or other structure.
    (A) Location. The PV disconnecting means shall be jnstalled
    at a readily accessible location either on the outside
    of a building or structure or inside
    nearest the point of
    entrance of the system conductors.

    705.22 Disconnect Device. The disconnecting means for
    ungrounded conductors shall consist of a manually or
    power operable switch(es) or circuit breaker(s) with the
    following features:
    (I) Located OUTDOORS where readily accessible...

    (...and then...why not "adjacent to the meter if possible", where the POCO wants a switch?!?)
    ----
    Readily Accessible
    What And Where In The NEC


    This phrase is used to describe the location of circuit breakers, for example, permitting ready access to turn the circuit off during times of emergency, when something malfunctions, or when working on the circuit or the electrical equipment in a de-energized condition, as normally required by NFPA 70E.

    However, the readily accessible requirement does not apply to all overcurrent devices. There are four exceptions to this rule: 

    1. For busways
    2. For supplementary overcurrent protection in accordance with 240.10
    3. For overcurrent devices in accordance with 225.40 where the feeder devices are not readily accessible if the branch-circuit devices are readily accessible and the same for service overcurrent devices are not readily accessible where the feeder or branch-circuit overcurrent devices are readily accessible


    http://www.ecmag.com/section/codes-s...ily-accessible

  10. #30
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    You should look at the 2017 version of the definition where they specifically excluded keys from the tools that are prohibited. It really does not make sense to broadly consider inside locations to be not readily accessible when there are plenty of facilities that have people inside the 24hrs a day. Even assuming that the inside of a building would be locked when no one is there isn't perfectly logical. There are a lot if items that code requires to be readily accessible that it doesn't make sense to broadly require be outside.

    So again, I think the fact that 705.12 does *not* say indoors is allowed, means that it isn't, so it should say so.
    Absolutely not. If the code doesn't explicitly require something then it's not required. The code can't possibly list every way of doing something that is allowed.

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