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Thread: Basic PV question

  1. #1
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    Basic PV question

    I own & operate a small company that does mainly residential service work and remodels, and am not familiar with PV work. Please forgive any mis-wording as I am not familiar with the terms used in this segment of our industry.

    On a residential remodel/addition that we started today, the general contractor needs to have a conduit removed while he tears out and rebuilds a wall. The 3/4" conduit may also have to be relocated depending on how the wall goes together. The conduit comes through the roof right below a set of PV panels and goes to a small breaker box with a backfed 2-pole breaker inside (I think this acts as a disconnect for firemen and service techs to kill PV power to the house). This box is located on the outside of the house. I have 8 years of commercial experience so I am comfortable with relocating the conduit.

    I would like to disconnect the THHN conductors (Black, Red, White, Green) at the above-mentioned breaker and pull them out of a section of the conduit while leaving the conductors connected on the roof. What precautions should I take when disconnecting and handling these wires?

    Thanks in advance and please let me know if more information is needed.

  2. #2
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    Quote Originally Posted by bei View Post
    I own & operate a small company that does mainly residential service work and remodels, and am not familiar with PV work. Please forgive any mis-wording as I am not familiar with the terms used in this segment of our industry.

    On a residential remodel/addition that we started today, the general contractor needs to have a conduit removed while he tears out and rebuilds a wall. The 3/4" conduit may also have to be relocated depending on how the wall goes together. The conduit comes through the roof right below a set of PV panels and goes to a small breaker box with a backfed 2-pole breaker inside (I think this acts as a disconnect for firemen and service techs to kill PV power to the house). This box is located on the outside of the house. I have 8 years of commercial experience so I am comfortable with relocating the conduit.

    I would like to disconnect the THHN conductors (Black, Red, White, Green) at the above-mentioned breaker and pull them out of a section of the conduit while leaving the conductors connected on the roof. What precautions should I take when disconnecting and handling these wires?

    Thanks in advance and please let me know if more information is needed.
    It makes a difference if those conductors carry AC or DC; is it a microinverter array or is/are there inverter(s) elsewhere in the system? Wiring with those colors implies AC, in which case as soon as they are disconnected from the service they are de-energized. If they are DC, however, they are likely still hot until they are disconnected from the modules on the roof. If they connect to a breaker in the MDP, though, they are AC.

  3. #3
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    Quote Originally Posted by ggunn View Post
    It makes a difference if those conductors carry AC or DC; is it a microinverter array or is/are there inverter(s) elsewhere in the system? Wiring with those colors implies AC, in which case as soon as they are disconnected from the service they are de-energized. If they are DC, however, they are likely still hot until they are disconnected from the modules on the roof. If they connect to a breaker in the MDP, though, they are AC.
    In either case will any harm be done if I simply tape the ends of the conductors and leave them disconnected while the construction progresses?

  4. #4
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    Quote Originally Posted by bei View Post
    In either case will any harm be done if I simply tape the ends of the conductors and leave them disconnected while the construction progresses?
    You really don't want to have live DC conductors lying around loose even if the ends are taped, but from what you described I think they are most likely AC conductors. If that is the case there shouldn't be a problem as long as you take care not to damage them.

  5. #5
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    Quote Originally Posted by ggunn View Post
    You really don't want to have live DC conductors lying around loose even if the ends are taped, but from what you described I think they are most likely AC conductors. If that is the case there shouldn't be a problem as long as you take care not to damage them.
    Thanks ggunn

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