250.64(E)

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svaurez

Member
Location
California
250.64(E)

Metal enclosures for grounding electrode conductors shall be electrically continuous from the point of attachment to cabinets or equipment to the grounding electrode and shall be securely fastened to the ground clamp or fitting.

What are they talking about here? Could someone describe an installation where this section would apply.
 

dereckbc

Moderator
Staff member
Location
Plano, TX
Re: 250.64(E)

They are talking about the raceway you might use to install the GEC in, from the cabinet or encloseure to the ground electrode like a conduit. The GEC has to be bonded at both ends of the raceway to minimize "choking effect", or put the raceway in parallel with the GEC.
 

svaurez

Member
Location
California
Re: 250.64(E)

The next section states that if the enclosure is not physically continuous I need to bond the conductor at both ends.

What if the enclosure IS physically continuous?
Do I still need to bond both ends?
 

ryan_618

Senior Member
Re: 250.64(E)

Notice that it states "continuous to the electrode". In my opinion, that would mean that your conduit would have to literally be attached to the electrode. How can this be achieved? I guess it is possible, but I don't think it is probable.

Then again, maybe I'm ready this wrong.
 

charlie

Senior Member
Location
Indianapolis
Re: 250.64(E)

I believe it means electrically continuous from one end to the other. This is the reason we (at my company) do not permit the supplemental GEC to run from the service, through the service raceway, through the meter fitting, and down to the ground rod. I believe the Code requires the GEC to be connected to the enclosures where it passes through and that would put the GEC in parallel with the grounded conductor in violation of 310.4. We permit the GEC to originate in but not pass through the meter fitting to solve that problem. :D
 
G

Guest

Guest
Re: 250.64(E)

Originally posted by svaurez:
250.64(E)

Metal enclosures for grounding electrode conductors shall be electrically continuous from the point of attachment to cabinets or equipment to the grounding electrode and shall be securely fastened to the ground clamp or fitting.

What are they talking about here? Could someone describe an installation where this section would apply.
Let's say you are running #6 bare solid copper armored cable and you use the proper fitting at the main panel so the AC is bonded to the panel.

You terminate the solid copper grounding wire in an acorn ground rod connector like this:



You FAIL to bond the AC to the rod and you leave the armor floating on ground rod end of the ground wire. The ground wire is secure and bonded at the ground rod end, but the armor is not. The armor has to be bonded at both ends. You need to use a fitting on the ground rod end that will allow the armor to bond to the ground rod.

[ October 06, 2003, 12:40 AM: Message edited by: awwt ]
 

earlydean

Senior Member
Re: 250.64(E)

They do make fittings for terminating conduit to the water pipe or ground rod. They also have means for terminating the GEC directly to the GE.
 

tom baker

First Chief Moderator
Staff member
Re: 250.64(E)

T&B and OZGedney makes fittings to bond the conduit to the water pipe. Another way is to use a grounding bushing on the end of the conduit, loop the GEC thru the grounding bushing and then hit the pipe ground clamp.
 

gwz2

Senior Member
Location
Indiana
Re: 250.64(E)

If the GEC passes through boxes, troughs, etc., the GEC is to be bonded to each item.
A set-screw locknut on the metal raceway entering the box type enclosures will bond the metal raceway ends to the metal enclosure.

See the Soares Book on Grounding.

gwz2
 
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