Page 1 of 2 12 LastLast
Results 1 to 10 of 14

Thread: UL508A grounding conductor

  1. #1
    Join Date
    Aug 2010
    Location
    Texas
    Posts
    272

    UL508A grounding conductor

    Is it allowed to use multiple conductors as grounding conductors? According to UL508A Table 75.1 minimum conductors size for 800A service disconnect is 2/0 (copper); can I use 2X2AWG instead?
    "Because it's there!"
    George Mallory

  2. #2
    Join Date
    Dec 2006
    Location
    Chapel Hill, NC
    Posts
    31,666
    I am unaware of any code stating the grounding electrode conductor cannot be paralleled. In a 400 amp service with 2 -200 amp discos we are allowed to run 2-#4's to the electrode(s). I am unaware of what UL 508A is stating.

  3. #3
    Join Date
    Aug 2010
    Location
    Texas
    Posts
    272
    Quote Originally Posted by Dennis Alwon View Post
    I am unaware of any code stating the grounding electrode conductor cannot be paralleled. In a 400 amp service with 2 -200 amp discos we are allowed to run 2-#4's to the electrode(s). I am unaware of what UL 508A is stating.
    Thanks. I also read UL508A and did not see anything against paralleling grounding conductors.
    "Because it's there!"
    George Mallory

  4. #4
    Join Date
    Jul 2006
    Location
    San Francisco, CA, USA
    Posts
    6,280
    I would still assume the same rules apply as to CCCs, i.e. not smaller than 1/0.
    __________________________________________________ ____________________________
    Many people are shocked when they discover I am not a good electrician...

  5. #5
    Join Date
    Dec 2006
    Location
    Chapel Hill, NC
    Posts
    31,666
    Quote Originally Posted by Jraef View Post
    I would still assume the same rules apply as to CCCs, i.e. not smaller than 1/0.
    That section does not refer to grounding electrode conductor's

  6. #6
    Join Date
    Jun 2006
    Location
    Ohio
    Posts
    20,261
    Quote Originally Posted by Dennis Alwon View Post
    That section does not refer to grounding electrode conductor's
    There is no section which says you can parallel a GEC using smaller conductors. So you want to parallel 'em. Okay... each has to be the required minimum size.
    I'll never get there. No matter where I go, I'm always here.

  7. #7
    Join Date
    Aug 2004
    Location
    Northern illinois
    Posts
    14,816
    The grounding electrode conductor is not part of the UL 508a panel. It is field wiring.
    Bob

  8. #8
    Join Date
    Jul 2003
    Location
    New Jersey
    Posts
    22,810
    Quote Originally Posted by Smart $ View Post
    There is no section which says you can parallel a GEC using smaller conductors. So you want to parallel 'em. Okay... each has to be the required minimum size.
    I agree, there is nothing in table 250.66 that states that you can use something other than the size GEC listed in the table.
    Rob

    Moderator

    All responses based on the 2014 NEC unless otherwise noted

  9. #9
    Join Date
    Dec 2006
    Location
    Chapel Hill, NC
    Posts
    31,666
    I thought the code was permissive---if it does say you can't then you can....you all are changing the rules....LOL

  10. #10
    Join Date
    Dec 2006
    Location
    Chapel Hill, NC
    Posts
    31,666
    Tell me this. I can run a smaller conductor for 2- 200 amp panels to each disconnect and be compliant. Can I run those separate grounding electrode conductor's (#4's) to the same meter instead of the disconnect? If I can run it to the disconnect why can't I run it to the meter instead? Seems no different than a parallel grounding electrode conductor.

    I have never done it but I can't seem to find where it may be non compliant.


    This may be a reason not to parallel.

    C) Continuous. Except as provided in 250.30(A)(5) and
    (A)(6), 250.30(B)(1), and 250.68(C), grounding electrode
    conductor(s) shall be installed in one continuous length
    without a splice or joint. If necessary, splices or connections
    shall be made as permitted in (1) through (4):
    (1) Splicing of the wire-type grounding electrode conductor
    shall be permitted only by irreversible compression type
    connectors listed as grounding and bonding equipment
    or by the exothermic welding process.
    (2) Sections of busbars shall be permitted to be connected
    together to form a grounding electrode conductor.
    (3) Bolted, riveted, or welded connections of structural
    metal frames of buildings or structures.
    (4) Threaded, welded, brazed, soldered or bolted-flange
    connections of metal water piping.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •