Results 1 to 9 of 9
  1. #1
    Join Date
    Jan 2011
    Location
    Portland, OR
    Posts
    149
    Post Likes

    Testing for proper grounding

    What is the best way to test for a "good" ground on a residential breaker box. What are the signs that the minerals in the soil around the grounding rod are used up, or the rod it's self is deteriorating.

  2. #2
    Join Date
    Dec 2012
    Location
    columbus, OH
    Posts
    6,782
    Post Likes
    Fluke has test instruments designed for such a thing. They are not cheap.

  3. Likes DavidDeBord liked this post
  4. #3
    Join Date
    Jan 2011
    Location
    Portland, OR
    Posts
    149
    Post Likes
    Thread Starter
    Nothing that can be checked with a conventional meter? Thanks for responding so quickly.By the way I'm from Wilmington, OH. Go Bucks.

  5. Likes DavidDeBord liked this post
  6. #4
    Join Date
    Aug 2009
    Location
    Maine
    Posts
    8,097
    Post Likes
    Mike holt did a thing on checking ground rod resistance. Put 120 volts to the ground rod and used an amp clamp.

  7. Likes DavidDeBord liked this post
  8. #5
    Join Date
    Jan 2011
    Location
    Portland, OR
    Posts
    149
    Post Likes
    Thread Starter
    Do you have a link to that test? Thanks for the response.

  9. #6
    Join Date
    Dec 2012
    Location
    columbus, OH
    Posts
    6,782
    Post Likes
    Quote Originally Posted by lytning View Post
    Mike holt did a thing on checking ground rod resistance. Put 120 volts to the ground rod and used an amp clamp.
    Yea, hows that work?

  10. #7
    Join Date
    Nov 2006
    Location
    Southeastern Pa
    Posts
    30,762
    Post Likes
    Quote Originally Posted by jason12000 View Post
    What is the best way to test for a "good" ground on a residential breaker box. What are the signs that the minerals in the soil around the grounding rod are used up, or the rod it's self is deteriorating.

    As said, the device is not cheap, and it tests two distances from the ground rod. It is specially designed for the task.

    AEMC-Understanding-Soil-resistivity-testing.png
    [Avatar photo from a Florida training accident. Everyone walked away.]
    2 Tim 3:16-17

    RSES CMS, HVAC Electrical Specialist
    Member, IAEI

    AOP Forum Rules:







  11. Likes DavidDeBord liked this post
  12. #8
    Join Date
    Jun 2013
    Posts
    67
    Post Likes
    If in doubt , you can drive a second ground rod ( at least 8' x 5/8" ) , at least 15 foot from the existing one & re-do the ground wire , w/o splices , to both . Run at least # 6 copper , in one continuous length from the service panel , to the 1st rod & then to the 2nd rod . I recommend 1 piece direct burial clamps , such as JAB58 .

    Or , in in further doubt , use 2 new copper clad / plated ground rods ? There are other ways to " make " ground electrodes .

    God bless
    Wyr

  13. Likes DavidDeBord liked this post
  14. #9
    Join Date
    Aug 2004
    Location
    SC
    Posts
    21
    Post Likes
    Easiest method to test ground resistance on a residential ground rod is with a clamp on ground resistance meter. Several companies have them including Fluke, Amprobe, AEMC etc. Most reputable electrical contractors should have one. Be sure that ground bar is bonded to neutral in service entrance panel to get correct reading.
    Testing the soil resistivity (mineral content, etc) is a whole different ball game and must be performed using the fall-of-potential testing method. Meters used for this test can be used to test ground resistance also. Grounding probes are driven at set distances from the ground rod depending on the depth of the grounding electrode. Resistance is measured at each interval. To use this method the neutral-to-ground bonding strap in the SE panel should be removed. Specific requirements and techniques are too involved for this discussion but this gives you the general idea.

Posting Permissions

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