This article was posted 03/10/2006 and is most likely outdated.

Grounding vs Bonding Online Training
 

 
Grounding vs Bonding: 250.80 Service Enclosures

March 10, 2006  

  View Comments | Add Comments | Notify Me When Comments Are Added  

PART IV. GROUNDING (BONDING) OF ENCLOSURE, RACEWAY, AND SERVICE CABLE  

Hi Res - Cable/DSL [4224Kb]
VIEWING Video FILE requires
Real Media Player [ FREE ]

    
Sections

250.80 Service Enclosures.

Metal raceways and enclosures containing service conductors must be grounded (bonded) to an effective ground-fault current path [250.4(A)(5)].

Exception: Metal elbows having 18 in. or more of earth cover aren’t required to be grounded (bonded) to an effective ground-fault current path. Figure 250–122



Figure 250–122
(Click on image to enlarge)

       

Copyright © 2005 Mike Holt Enterprises,Inc.
1-888-NEC-CODE (1-888-632-2633)

 

Comments
  • The ALLOWANCE for the un-gonded stee elbows is to serve for long and difficult pulls. On a long pull the pull rope can dig into the inside surface of the elbow, saw through to the earth, and keep pulling untill the wire gets to the little slot and stops. The steel elbows are not germane to the question of overcurrent protection below the meter.

    If you doubt the ability of the rope to saw the pipe, try sawing a nylon string across a PVC conduit. I have used this method to cut pipe that was down in a trench without having to open a bigger hole below the conduit for the hack saw.

    On a shopping mall job in Pensacola some 30 years ago, the conduit was in, the pole bases poured, and the asphalt finished wehn the contractor started pulling the long runs of wire for the extremely high light standards. When every way failed to pull the wire the last few feet, from either direction, the contractor gave up and dug down to the conduit. Finding the rope some foot out in the dirt and a slot in the elbow explained why the wire would not pull!

    Lynn Adams

Reply to this comment
* Your Name:
   Your name will appear under your comments.

* Your Email:
   Your email address is not displayed.
* Comments:

This newsletter is closed to new comments.

Email Notification Options:
Notify me when a reply is posted to this comment
Notify me whenever a comment is posted to this newsletter