Page 1 of 2 12 LastLast
Results 1 to 10 of 11

Thread: Service Entrance Grounding Wire Sise

  1. #1
    Join Date
    Sep 2018
    Location
    Fort Myers, FL US
    Posts
    3

    Service Entrance Grounding Wire Sise

    We are upgrading a 200 AMP service to a 400 AMP. My understanding from the code is this would require a #4 bare copper wire for grounding if the new service entrance disconnect. Just looking for confirmation.


    Sent from my iPhone using Tapatalk

  2. #2
    Join Date
    Dec 2006
    Location
    Chapel Hill, NC
    Posts
    33,733
    I assume you mean the grounding electrode conductor? If so that would depend on how your service is install. For instance, if you have 2- 200 amp service panels then you could run 2- runs of #4 to the grounding electrode- water pipe???... or you could run a #2.

    If you use a meter main combo bo then you need a 1/0 grounding electrode conductor.
    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
    Join Date
    Jul 2003
    Location
    New Jersey
    Posts
    26,018
    Quote Originally Posted by SteveHayden View Post
    We are upgrading a 200 AMP service to a 400 AMP. My understanding from the code is this would require a #4 bare copper wire for grounding if the new service entrance disconnect. Just looking for confirmation.
    There are many varying factors. What do you mean by "grounding"? If you're referring to the grounding electrode conductor (GEC) as Dennis mentioned then you would need to mention the type of electrode you're using. A ground rod requires #6, a CEE #4 and a water pipe a #1/0 or #2.

    Welcome to the Forum.
    Rob

    Moderator

    All responses based on the 2014 NEC unless otherwise noted

  4. #4
    Join Date
    Sep 2018
    Location
    Fort Myers, FL US
    Posts
    3
    Not a meter main combo. 400 amp meter feeding two 200 amp panels. The main ground off of the meter I believe just needs to be #4 bare copper.


    Sent from my iPhone using Tapatalk

  5. #5
    Join Date
    Dec 2006
    Location
    Chapel Hill, NC
    Posts
    33,733
    Quote Originally Posted by SteveHayden View Post
    Not a meter main combo. 400 amp meter feeding two 200 amp panels. The main ground off of the meter I believe just needs to be #4 bare copper.


    Sent from my iPhone using Tapatalk

    No-- It needs to be #2 but it depends on the service conductor wire size. #4 is good for 200 amp not 400 amp. The wire to the ground rods only needs to be #6
    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



  6. #6
    Join Date
    Dec 2006
    Location
    Chapel Hill, NC
    Posts
    33,733
    Look at the notes to table 250.66
    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
    Join Date
    Jul 2003
    Location
    New Jersey
    Posts
    26,018
    Quote Originally Posted by SteveHayden View Post
    Not a meter main combo. 400 amp meter feeding two 200 amp panels. The main ground off of the meter I believe just needs to be #4 bare copper.
    What is a "main ground"?
    Rob

    Moderator

    All responses based on the 2014 NEC unless otherwise noted

  8. #8
    Join Date
    Feb 2003
    Location
    Fl
    Posts
    17,332
    Quote Originally Posted by SteveHayden View Post
    Not a meter main combo. 400 amp meter feeding two 200 amp panels. The main ground off of the meter I believe just needs to be #4 bare copper.

    What type of electrode is it connecting to? How many different types of electrodes are present?

    Roger
    Moderator

  9. #9
    Join Date
    Dec 2007
    Location
    NE Nebraska
    Posts
    38,252
    It is sized per the incoming ungrounded conductor. You said you have a 400 amp meter and 2-200 amp panels. That incoming conductor does not necessarily need to be a 400 amp conductor - with multiple disconnecting means it can be sized per calculated load. Or if you had a long run and increased size for voltage drop it very well may be large enough you need more than #2 GEC. Bottom line is 400 amps doesn't mean a lot for sizing this conductor, it only tells us what might be typical.
    I live for today, I'm just a day behind.

  10. #10
    Join Date
    Mar 2014
    Location
    McKinney, Texas
    Posts
    1,449
    Quote Originally Posted by SteveHayden View Post
    We are upgrading a 200 AMP service to a 400 AMP. My understanding from the code is this would require a #4 bare copper wire for grounding if the new service entrance disconnect. Just looking for confirmation.


    Sent from my iPhone using Tapatalk
    Greetings,

    Many numbers being thrown out in this thread but I feel you have asked a question with many open-ended assumptions.

    (1) What Grounding Electrode do you have on your Grounding Electrode System?
    (2) What are the "actual" sizes of the conductors you are installed versus just giving ampacity values, always hate to assume others know how to "size" conductors for a specific value specified.

    As others have said, if your existing GES was comprised of "Ground Rod(s)" then 6 AWG CU would be all that is needed. However, I elect to not assume anything since 4 AWG CU is also the minimum required size for a CEC "Concrete Encased Electrode" as well so again without specifics you get general responses.
    *All code responses are based on the 2017 National Electrical Code®[NEC®]

Posting Permissions

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