×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Ground Interconnections

Ground Interconnections

Ground Interconnections

(OP)
Should the ground rod of the utility transformer be connected/bonded to the service entrance ground rod. Is there a minimum separation between the two system rods.

RE: Ground Interconnections

In the US, they need to be bonded together.  

RE: Ground Interconnections

Hi dcp;
When the original poster says the ground rod of the distribution transformer, I visualize a pole mounted transformer with a ground rod at the base of the pole.
respectfully

RE: Ground Interconnections

Normally, in the US, the connection between the utility ground at the transformer and the service entrance ground is through the service drop neutral.  Both ground rods are connected to the neutral.

RE: Ground Interconnections

waross - that's what I visualize too.  

RE: Ground Interconnections

Hi fellows;
I think we are basically in agreement with the connections.
We may have a disagreement on terminology.
In the building the neutral system will be connected to the ground grid in one place only.
At the pole, the utility neutral, which often serves as both primary and secondary neutral, will be connected to ground rods at regular intervals. One point of connection to ground is always at a transformer. This is the utility's ground system.
If the neutral is supplied to the building it will be grounded at one point to the building ground grid.
The neutral will also be connected to the utility's ground system at the pole.
The point of confusion seems to be the word "Bonding".
To me, bonding the ground rods together implies that another cable is run directly from one ground rod to the other. This may have been the intent of the OP's question.
I do not think that this is required or allowed.
I am not sure about the spacing issue. Is anyone familiar with the applicable NEC rules?

RE: Ground Interconnections

waross,

I think we're all saying the same thing.  NEC defines bonding as a "permanent joining of metallic parts to form a path that ensures electrical continuity".  But I'm OK with saying that that ground rods are "connected" together, if that sits better with you.  

I think spacing between the two ground rods is not relevant, at least in the US, since they are electrically connected.  

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources