This article was posted 02/24/2006 and is most likely outdated.

Grounding vs Bonding Online Training
 

 
Grounding vs Bonding: 250.68 Grounding Electrode Conductor Termination

February 24, 2006  

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PART III. GROUNDING ELECTRODE SYSTEM AND GROUNDING ELECTRODE CONDUCTOR  Hi Res - Cable/DSL [24352Kb]
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250.68 Grounding Electrode Conductor Termination.

(A) Attachment Fitting. The grounding electrode attachment fitting must be accessible.

Exception 1: The grounding electrode attachment fitting to an encased or buried grounding electrode isn’t required to be accessible. Figure 250–119

Author’s Comment: When the grounding electrode attachment fitting is encased in concrete or buried, it must be listed and identified for this purpose [250.70].
Exception 2: An exothermic or irreversible compression connection to fireproofed structural metal isn’t required to be accessible.

(B) Effective Ground-Fault Current Path. To ensure a permanent and effective grounding path for an underground metal water pipe electrode, a bonding jumper must be installed around insulated joints and equipment likely to be disconnected for repairs or replacement. Figure 250–120

Author’s Comment: Continuity of the conductive bonding path for metal water piping as required by 250.104(A) cannot rely on water meters, filtering devices, or similar equipment [250.53(D)(1)].



Figure 250–119
(Click on image to enlarge)


Figure 250–120
(Click on image to enlarge)

     

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Comments
  • My E-mail address changed to rosejc@iowatelecom.net

    Jim Rose
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  • Reply from: Tara Moffitt   
    Any time your e-mail address changes you can update that by clicking on newsletters and then change e-mail address. OR Go directly there with this link: http://www.mikeholt.com/newslettersRegister.php?action=modify

    I'll go ahead and take care of this for you, but just wanted anyone else that may encounter this issue to know how to do this.

    Thank you.
    Reply to Tara Moffitt


  • How would this work with a brass back flow preventor in the water line

    Norman Odeneal
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  • It would be worth noting that more and more civil and plumbing types are using/allowing the use of plastic (non-metallic) piping for the underground portion of the domestic and fire water services into many commercial buildings, with maybe only the underground elbow and riser to above the floor slab being metal. NFPA 70 does not allow the use of water service piping as an electrode unless there is at least 10 feet of metal piping underground, and in contact with earth. We are discovering numerous instances where the contractor bonded the grounding electrode conductor to the incoming water piping, only to discover there was no metal piping under the slab, except the riser (way less than the required 10 feet). As the use of plastic piping is becoming the "norm" vs. the exception, more thought should be given by the code writing committees to rewording article 250, with more warnings and more emphasis on the other electrodes. And, designers must take a more agressive stance in coordinating this issue with the plumbing and civil designers, to resolve this during design instead of after the installation is complete and unsafe (when the contractor did what he is "told" or what showed on the drawings vs. doing the right thing).

    Tom Montgomery
    Reply to this comment
  • Reply from: Mike Holt   
    You make an excellent point. I will propose for the 2011 NEC that the Water Pipe not be used as the required grounding electrode.
    Reply to Mike Holt



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