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equipment grounding conductor

    • 6 posts
    July 7, 2019 12:02 PM PDT

    within a MC cable at 32 kV what size equipment grounding conductor is needed? if the conductors is 1/0 awg

    • 103 posts
    July 7, 2019 12:49 PM PDT

    See 250.122

    If your OCPD is 200A or smaller a six gauge should be sufficient. 

    Six gauge is the smallest allowed, can be larger.

    This post was edited by Steve Ward at July 7, 2019 12:51 PM PDT
    • 157 posts
    July 7, 2019 1:00 PM PDT

    As Steve mentioned the equipment grounding conductor is based on the overcurrent protective device not the size of the wire.  You also need to mention whether or not the wire is copper or aluminum but in this case since the voltage is more than 1000 the equipment grounding conductor cannot be smaller than #6 copper or 4 Aluminum


    250.190 (C) Equipment Grounding Conductor. Equipment grounding
    conductors shall comply with 250.190(C)(1) through (C)(3).
    (1) General. Equipment grounding conductors that are not
    an integral part of a cable assembly shall not be smaller than
    6 AWG copper or 4 AWG aluminum.
    (2) Shielded Cables. The metallic insulation shield encircling
    the current carrying conductors shall be permitted to be used
    as an equipment grounding conductor, if it is rated for clearing
    time of ground-fault current protective device operation without
    damaging the metallic shield. The metallic tape insulation
    shield and drain wire insulation shield shall not be used as an
    equipment grounding conductor for solidly grounded systems.
    (3) Sizing. Equipment grounding conductors shall be sized in
    accordance with Table 250.122 based on the current rating of
    the fuse or the overcurrent setting of the protective relay.