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Thread: Electrode sizing

  1. #1
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    Electrode sizing

    For a 200 amp service, resi., 5/8 by 8' is required. Does a 400amp/320 continuous service require a 3/4 by 10' electrode? I feel like this was something that I had heard about. TIA!

  2. #2
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    Quote Originally Posted by C_Hill View Post
    For a 200 amp service, resi., 5/8 by 8' is required. Does a 400amp/320 continuous service require a 3/4 by 10' electrode? I feel like this was something that I had heard about. TIA!

    No, the service can be 6000 amps and the ground rod only needs to be 5/8" x 8' or 1/2" by 8' if listed. BTW, welcome to the forum
    They say I shot a man named Gray and took his wife to Italy
    She inherited a million bucks and when she died it came to me
    I can't help it if I'm lucky



  3. #3
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    Thanking you, Sir.

  4. #4
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    How many rods are you installing?
    Rob

    Moderator

    All responses based on the 2014 NEC unless otherwise noted

  5. #5
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    Code Reference

    But Where in the NEC does it reference the size and depth of the Ground Rod?

  6. #6
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    Quote Originally Posted by ManofSteele View Post
    But Where in the NEC does it reference the size and depth of the Ground Rod?

    Here for one

    250.52(A)(5) Rod and Pipe Electrodes. Rod and pipe electrodes shall
    not be less than 2.44 m (8 ft) in length and shall consist of the
    following materials.
    (a) Grounding electrodes of pipe or conduit shall not be
    smaller than metric designator 21 (trade size 3∕4) and, where of
    steel, shall have the outer surface galvanized or otherwise
    metal-coated for corrosion protection.
    (b) Rod-type grounding electrodes of stainless steel and
    copper or zinc coated steel shall be at least 15.87 mm (5∕8 in.) in
    diameter, unless listed.

    Also

    250.53(G) Rod and Pipe Electrodes. The electrode shall be installed
    such that at least 2.44 m (8 ft) of length is in contact with the
    soil. It shall be driven to a depth of not less than 2.44 m (8 ft)
    except that, where rock bottom is encountered, the electrode
    shall be driven at an oblique angle not to exceed 45 degrees
    from the vertical or, where rock bottom is encountered at an
    angle up to 45 degrees, the electrode shall be permitted to be
    buried in a trench that is at least 750 mm (30 in.) deep. The
    upper end of the electrode shall be flush with or below ground
    level unless the aboveground end and the grounding electrode
    conductor attachment are protected against physical damage as
    specified in 250.10.
    They say I shot a man named Gray and took his wife to Italy
    She inherited a million bucks and when she died it came to me
    I can't help it if I'm lucky



  7. #7
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    Quote Originally Posted by C_Hill View Post
    For a 200 amp service, resi., 5/8 by 8' is required. ...
    Not if the rod is listed.

  8. #8
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    Quote Originally Posted by jaggedben View Post
    Not if the rod is listed.
    If you want to go one step further you could say that rods are never required.
    Rob

    Moderator

    All responses based on the 2014 NEC unless otherwise noted

  9. #9
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    Got it, Thanks

  10. #10
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    In what situations one might install 3/4 by 10' ground rod instead of 5/8 by 8' ground rod?

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