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Discussion Starter · #1 · (Edited)
Does the EGC (equipment grounding conductor) have to be run with the ungrounded conductors of a line-to-line circuit (208 V)back to the originating breaker panel? or can it be just run to another piece of equipment that is fed from another panel?

edit: Also, could you provide a NEC code reference?

Thank you,
Mike
 

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Not to side-step your question, but why would a 208V circuit, normally found in a commercial setting, be run without a EGC in the first place? What kind of wiring method was used?
 

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Discussion Starter · #3 ·
Not to side-step your question, but why would a 208V circuit, normally found in a commercial setting, be run without a EGC in the first place? What kind of wiring method was used?

In an apartment building, the a/c condenser units are grouped together in the rear of the buildings. A unit was being serviced and the a/c tech said that the egc was open somewhere in the interior walls of the building between the panel and the unit's disconnect so he was going to run a #10 conductor to the adjacent a/c's units disconnect and connect to its egc which is fed from another apartments panel. He said that this would solve the problem temporarily until the wiring could be repaired properly.

Mike
 

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Before myself or SD515 can comment little more on this one what type of wiring methold it did use like NM cable or EMT conduit or others ??

Once we know what type of wiring methold it did bring to the disconnect swtich we will go from there.

Merci,
Marc
 

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Discussion Starter · #5 ·
Before myself or SD515 can comment little more on this one what type of wiring methold it did use like NM cable or EMT conduit or others ??

Once we know what type of wiring methold it did bring to the disconnect swtich we will go from there.

Merci,
Marc
NM cable from panel to a/c disconnect which is mounted on the brick exterior wall and then UF from a/c disconnect to a/c compressor.

What if it would have been EMT? Would that make it legal?

Mike
 

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A unit was being serviced and the a/c tech said that the egc was open somewhere in the interior walls of the building between the panel and the unit's disconnect
Not to doubt the condition of the EGC, but why was the A/C tech checking the condition of the ground path since the ground path will not affect the operation of the condenser?
The first question would be, is there an EGC coming into the disconnect.
Second question would be, if this is in romex as stated, how would the ground wire get broken without any damage to the other conductors in the romex cable.
 

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Discussion Starter · #7 · (Edited)
Not to doubt the condition of the EGC, but why was the A/C tech checking the condition of the ground path since the ground path will not affect the operation of the condenser?
I have no idea.

The first question would be, is there an EGC coming into the disconnect.
Yes..and there is no continuity between the end of the egc in the disconnect and the end of the egc in the panel.

Second question would be, if this is in romex as stated, how would the ground wire get broken without any damage to the other conductors in the romex cable.
Again, I have no idea.

My original question was:
Does the EGC (equipment grounding conductor) have to be run with the ungrounded conductors of a line-to-line circuit (208 V)back to the originating breaker panel? or can it be just run to another piece of equipment that is fed from another panel?


Mike
 

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My original question was:
Does the EGC (equipment grounding conductor) have to be run with the ungrounded conductors of a line-to-line circuit (208 V)back to the originating breaker panel? or can it be just run to another piece of equipment that is fed from another panel?
Mike


Sorry for the delay Mike. I checked various sections of the code, long story short, my interpretation tells me…Yes, the EGC has to be run with the circuit conductors. To be honest with you, I haven’t yet found any actual wording that says it has to terminate at the point of origin. I may have missed something. For the most part, I believe their intention is that it would, in order to provide a low-impedance, effective ground fault path, that cannot be disturbed by disconnecting another piece of equipment not associated with that circuit.

Personally, I would not advocate the use of another piece of equipment fed from another panel as the EG path. True both panels should bonded back at the same service disconnect, but I don’t believe that is the intention of the code.

Referencing NEC 2008, 250.2, 250.4, 250.118, 250.134, 300.3(B) as applied to your situation.

I am more than willing to listen to anyone else that wants to chime in on this…

The following was taken from ECMWEB.COM, posted 4/23/2004

In general, under what condition in an alternating current feeder or branch circuit is an equipment grounding conductor permitted outside of a cable or raceway?
A) under no condition
B) as part of a high-impedance grounded neutral system
C) on ground-fault circuit interrupter protected circuits
D) any time
Answer: A
Explanation: There are five sections of the 2002 NEC that don't permit an equipment grounding conductor to be installed on the outside of a cable or raceway:
250.118
250.134(B)
300.3(B)(2)
300.5(I)
300.20(A).
It has been proven that separating the equipment grounding conductor from the circuit conductors greatly increases the impedance of the circuit. Separation of these conductors will increase the inductive reactance of an AC circuit, which increases grounding circuit conductor impedance values. The impedance of the equipment grounding conductor of a circuit should be kept as low as practicable. Excessive separation can render an adequately sized equipment grounding conductor ineffective in carrying enough current to operate the circuit overcurrent protective device in a reasonable amount of time to clear the fault.
 

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Discussion Starter · #9 ·
Kyle,

Thank you very much for the detailed explanation. I genuinely appreciate it.

Is the 2002 NEC, that you referenced, available online for viewing?

Regards,
Mike
 

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You're welcome :thumbsup:

Try
http://en.wikipedia.org/wiki/National_Electrical_Code

I Googled ‘national electrical code online’ Not 100% sure you can access the code online without paying for it. I’ve not tried before to read the code book online, I use my printed edition. You might check your local library…see if they have a current edition you can look at.

The first part of my post is actually my digging through the 2008 NEC. The second was a clip from ECMWEB.COM and their referencing of the 2002 code. ECM’s website is a great place to look also. They use references of code, and explain a lot of things in ‘lay-mans’ terms, and intention of the code.

While changes occur in between code cycles, much of the basic, fundamental things stay the same. But it’s always best to check the current code edition your area is on.

And P.S. You had a great question here...made me dig alot...trying to not leave any stone unturned.
 
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