GEC on the outside of the conduit?

mvasmvas Registered Users Posts: 383 ✭✭✭
I am planning on running the GEC ( 4 AWG Solid ) on the outside of the conduit from the Inverter back to the Main Service Panel. Is it OK ( per NEC Code ) to cable-tie the GEC to the outside of the 3/4" EMT (which contains the Black, White & EGC Green to AC breaker).
    Pushing the 4 AWG Solid through the conduit and then adding Ground Bushings would be my 2nd choice.

Comments

  • BB.BB. Super Moderators, Administrators Posts: 31,618 admin
    If you are doing this with an inspectiion--You need to check with your inspector to see if this is acceptable.

    In general, AC wiring is required to run all together in the same conduit/hole through the metal box. If you, for example, put hot through one hole and the white through another hole, the two wires act like a transformer and cause current to flow in the box sheet metal (and can cause overheating of the sheet metal).

    Ground wires do not normally carry current (just fault current)--But it does push the envelope on code (as I understand the reasons).

    Why do you want to run it separately?

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • mvasmvas Registered Users Posts: 383 ✭✭✭
    edited December 2016 #3
    The inspector is less than helpful => "consult the NEC book".
    Yes, I do have the 240V (Red & Black) wires and the EGC Green (all 10 AWG) inside the conduit.
    The GEC is not required to be inside the Conduit because there is an EGC inside.
    There is no White Neutral Wire.
    Putting the GEC inside the EMT causes the choke issue which then requires Ground Bushings.
    And pulling the 4 AWG wire inside conduit is not easy.
     
  • BB.BB. Super Moderators, Administrators Posts: 31,618 admin
    Then, I would not worry about the separate grounding wire outside the conduit... As long as you meet code inside the conduit, and have the required grounding rod--Then anything else you do would not be something the code guy should worry about.

    -Bill (just guessing) B.
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • mike95490mike95490 Solar Expert Posts: 9,262 ✭✭✭✭✭
    BB. said:
    Then, I would not worry about the separate grounding wire outside the conduit... As long as you meet code inside the conduit, and have the required grounding rod--Then anything else you do would not be something the code guy should worry about.

    -Bill (just guessing) B.
    I'll disagree  Sometimes, "more" grounding  can invite troubles, and I''ll admit to not knowing what code in your area requires.  I'd run optional wires AFTER the inspector has left.   If they are not optional, then you will be only told you don't pass. 
    As long as you are not inviting a lightning stroke into your house envelope after the inspector leaves.
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  • inetdoginetdog Solar Expert Posts: 3,123 ✭✭✭✭
    edited January 2017 #6
    An EGC (equipment grounding conductor, commonly referred to as "ground") must either be the metal of the conduit itself or be inside the conduit with the rest of the circuit wires.
    A GEC (ground electrode conductor) on the other hand is not a circuit conductor at all and in addition to being sized differently can be outside the conduit.
    A wire from one ground electrode to another is usually technically a bonding jumper (whose size must equal the GEC associated with the electrodes) and not a GEC, and can again be outside the conduit.
    In some situations (most under current NEC) you must have an EGC (conduit or inside) even if you put a GEC or bonding jumper outside the conduit.

    Clear as mud, right?
    SMA SB 3000, old BP panels.
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