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Thread: PV 690.31 (E) Metal Raceway ?!

  1. #1
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    PV 690.31 (E) Metal Raceway ?!

    Residential PV Systems are popping up here quicker then weeds during rainy season. As inspectors we’re straining hard to be sure we’re understanding the installations and correctly applying the code. We’ve hit a snag at NEC 690.31 (E). The question is EXACTLY WHICH conductors are required to be in metal raceways or metal enclosures? The title to this section seems to be clear, however when you get into the text it becomes a little murky. We are seeing a lot of micro inverter installations and are wondering if other AHJ’s are requiring the wiring (inside the building) FROM THE INVERTER to be in metal raceways or enclosures?

  2. #2
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    Quote Originally Posted by TopGunTom View Post
    Residential PV Systems are popping up here quicker then weeds during rainy season. As inspectors we’re straining hard to be sure we’re understanding the installations and correctly applying the code. We’ve hit a snag at NEC 690.31 (E). The question is EXACTLY WHICH conductors are required to be in metal raceways or metal enclosures? The title to this section seems to be clear, however when you get into the text it becomes a little murky. We are seeing a lot of micro inverter installations and are wondering if other AHJ’s are requiring the wiring (inside the building) FROM THE INVERTER to be in metal raceways or enclosures?
    I require everything to be in conduit inside the building. I hope that's the right call
    "Appliances and wiring will burn out to protect fuses"

  3. #3
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    May 2009
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    I think metal conduit must be used up to the disconnect. Practically speaking, that would probably mean that the metal conduit would be run all the way to the loadcenter. Unless there is a disconnect inside, romex couldn't be used anyway from that point to the loadcenter because romex isn't allowed for outside use.

    For an example where no metal conduit might be required with an Enphase Microverter system, I think it would be code compliant to run UF from the disconnect all the way to the loadcenter. The interesting thing is that Enphase says their cord connectors qualify as disconnnects. So it seems to me that there are some situations where no metal conduit would be anywhere on the branch circuit. You might have some solar panels in the backyard, run the microinverter connector to the jbox at the panel mounting area, and then run UF directly back to the loadcenter. I personally think a dedicated disconnect switch is required at the panel mount area, but either way, I don't think metal conduit is technically required all the way back to the loadcenter.

  4. #4
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    I did some more searching on Enphase's website and they have a few comments in the NEC questions page. I disagree with their comment that romex can be run to a junction box on the roof, because it would be outdoor. But I agree with the point is that metal conduit is not required.

    http://www.enphaseenergy.com/downloa...CheatSheet.pdf

    690.31(B) - Single conductor cable
    ROMEX can be run in the attic through a roof penetration to a junction box on
    the roof

    690.31(E) - PV output circuits in metallic raceways
    Tray cable is acceptable to bring AC to the first micro-inverter in the branch

  5. #5
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    Quote Originally Posted by TopGunTom View Post
    Residential PV Systems are popping up here quicker then weeds during rainy season. As inspectors we’re straining hard to be sure we’re understanding the installations and correctly applying the code. We’ve hit a snag at NEC 690.31 (E). The question is EXACTLY WHICH conductors are required to be in metal raceways or metal enclosures? The title to this section seems to be clear, however when you get into the text it becomes a little murky. We are seeing a lot of micro inverter installations and are wondering if other AHJ’s are requiring the wiring (inside the building) FROM THE INVERTER to be in metal raceways or enclosures?
    690 is one of those chapters where it is very important to understand the definitions at the front of the chapter to be able to understand how to apply the code. 690.31(E) is talking about DC wiring. In particular it is talking about "photovoltaic source circuits" and "photovoltaic output circuits". If you look at the definitions, you will find that neither of those types of circuits occur after the inverter, and the circuits after the inverter are not DC. 690.31(E) does not apply to the wiring after the inverter. Look carefully at the definitions of "Photovoltaic Output Circuit" and "Inverter Output Circuit" 690.31(E) is talking about the former, not the latter.

  6. #6
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    The conductors from the array or PV source to the first disconnect, need to be in metal conduit or metal wire way. Notice there is not a maximum distance to the first disconnect.

  7. #7
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    Thank you all for your responses. The rest of the story is that my three co-inspectors are saying that the wires FROM THE INVERTER need to be in conduit. I just can’t see where the actual code supports that. The title of this section pretty much seems to nail it right up front... Direct-Current Photovoltaic Source and Output Circuits Inside a Building

  8. #8
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    Quote Originally Posted by TopGunTom View Post
    Thank you all for your responses. The rest of the story is that my three co-inspectors are saying that the wires FROM THE INVERTER need to be in conduit. I just can’t see where the actual code supports that. The title of this section pretty much seems to nail it right up front... Direct-Current Photovoltaic Source and Output Circuits Inside a Building
    The code says what the code says. I've seen setups where the inverter is mounted under the array on the roof, and its ac from there down to the disconnecting means. That is not required to be in metal conduit per code, but for the life of me, I cannot make the logical distinction between the two types, unless those microconverters also have built in overload and short circuit protection. (Which I do not know if they do) Might be a reasonable thing to submit on for the next code cycle.
    85deg. an Sunny today.

  9. #9
    Join Date
    Oct 2009
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    Hey TopGunTom
    If you read carefully it explains it:

    Where direct current photovoltaic
    source or output circuits of a utility-interactive inverter
    from a building-integrated or other photovoltaic system are
    run inside a building or structure, they shall be contained in
    metallic raceways or metal enclosures from the point of penetration
    of the surface of the building or structure to the first
    readily accessible disconnecting means. The disconnecting
    means shall comply with 690.14(A) through 690.14(D).

  10. #10
    Join Date
    Oct 2009
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    Also again:

    Where direct current photovoltaic
    source or output circuits of a utility-interactive inverter
    from a building-integrated or other photovoltaic system are
    run inside a building or structure, they shall be contained in
    metallic raceways or enclosures from the point of penetration
    of the surface of the building or structure to the first
    readily accessible disconnecting means
    . The disconnecting
    means shall comply with 690.14(A) through 690.14(D).

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