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#83129 - 01/14/03 01:22 AM grounding conductors in EMT  
elecbob  Offline
Member
Joined: Aug 2002
Posts: 141
WA
Is there an NEC requirement that conductors, such as those from the circuit breaker panel to the cold water pipe, be insulated if they are ran through metal raceways such as EMT or metal wiremold?
Thanks in advance.
Bob


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#83130 - 01/14/03 05:54 AM Re: grounding conductors in EMT  
Gwz  Offline
Member
Joined: Apr 2002
Posts: 197
It appears you are referring to the Grounding Electrode Conductor (GEC) which must be installed as per 250.64(E) {conductor bonded to each end of the metal raceway enclosing the GEC}.

To answer the question of insulated conductor, the answer would be " NO" for copper GEC and maybe for Aluminum GEC. See 250.64(A).


#83131 - 01/14/03 09:18 AM Re: grounding conductors in EMT  
Redsy  Offline
Member
Joined: Mar 2001
Posts: 2,056
Bucks County PA
250.118(1) permits an uninsulated EGC.


#83132 - 01/15/03 12:05 AM Re: grounding conductors in EMT  
Gwz  Offline
Member
Joined: Apr 2002
Posts: 197
When he said ' cold water pipe ' I am assuming GEC.

Aluminum Conductor in/near earth has restrictions.


#83133 - 01/15/03 08:07 PM Re: grounding conductors in EMT  
wiking  Offline
Junior Member
Joined: Dec 2002
Posts: 32
Florida, USA
Its my understanding that if you run the grounding electrode in a metal pipe then it has to be bonded to the metal pipe. Something about setting up electromagnetic waves or something. If we do it we use a pipe nail or a clamp to make it continuous with the pipe its in although if it was bare it would seem like it would naturally be in contact. Thats why we usually run it in pvc. I hope i understood what you were getting at.


#83134 - 01/16/03 08:41 AM Re: grounding conductors in EMT  
Gwz  Offline
Member
Joined: Apr 2002
Posts: 197
What is a ' pipe nail ' that would bond the GEC to each end of a metal raceway ?

Note, a metal raceway enclosing a GEC could be a metal - wireway, junction box, trough, wiremold, etc.

The GEC must be bonded to both ends of a metal enclosure - 250.64(E).


#83135 - 01/16/03 09:03 AM Re: grounding conductors in EMT  
Redsy  Offline
Member
Joined: Mar 2001
Posts: 2,056
Bucks County PA
Sorry about the mix-up. (EGC v. GEC)
I should have read more caerefully


#83136 - 01/20/03 01:41 AM Re: grounding conductors in EMT  
mike knight  Offline
Junior Member
Joined: Oct 2002
Posts: 5
Gwz
it seems to me that 250.64e says you have to bond each end of a metal raceway if it is not electrically continous. if you used one peice of emt to enclose a gec wouldnt that be electrically countinous?


#83137 - 01/20/03 08:29 AM Re: grounding conductors in EMT  
Gwz  Offline
Member
Joined: Apr 2002
Posts: 197
When an GEC is inclosed in a metal raceway, standard locknuts, etc. are not considered 'continuous' unless items are bonded together.

See examples in figures 7-13 and 7-14 of the 8th Edition of the Soares Book on Grounding.

In figure 7-14, I believe, a 'setscrew locknut' would serve the purpose of the bonding bushing in the panelboard/conduit connection and also for the conduit to enclosures of figure 7-13.


#83138 - 01/22/03 12:27 AM Re: grounding conductors in EMT  
harold endean  Offline
Member
Joined: Feb 2002
Posts: 2,233
Boonton, NJ
Isn't there something in the code about concentric knockouts? They have to be rated for the voltage? I believe it has to do with 480 volts etc. My code book is in the office.

Harold


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