Ground wire

[EdR]

Is a ground wire required to be provided from a distribution panel feeding a sub panel?

 

[480sparky]

No. Any method mentioned in 250.118 can be used.

But it is required to be grounded per 250.134.

 

[acrwc10]

Is a ground wire required to be provided from a distribution panel feeding a sub panel?

You need to give up more information, how is the panel fed, where is the panel ?

 

[tryinghard]

Is a ground wire required to be provided from a distribution panel feeding a sub panel?

Two questions you have to answer yourself are:
1) In the event of a short does the current have an effective ground fault current path to its source other than earth?
2) If trying to qualify bonding the neutral at the subpanel does this bond establish any parallel path to its source on item other than conductors?

See 250.4(3)-(5); remember shorts are not trying to return to earth they are trying to return to their source. The earth is not an effective ground fault path because its resistance is unknown at any given moment. The earth ground electrode and conductor only exist to route ?lightning, line surges, or unintentional contact with higher-voltage lines? (250.4(A)(1)).

Read parts 5 & 6 of Article 250, parallel equipment grounding is most common today with metallic conduit, and bonding, 250.118 lists the types of EGC?s we must use.

Returning neutral (grounded conductor) current is only allowed on a purposeful conductor and nothing else, to contain its current. Returning current will travel ALL paths to its source ? not just the path of least resistance ? therefore the neutral rarely if ever is allowed to bond common to ground at any distribution past the service disconnect (250.24(A)(5) & 250.142(B). Unless this distribution is for a transformer see 250.30.

 

[dcspector]

You need to give up more information, how is the panel fed, where is the panel ?

Great point! I was posting when you did sorry. I see 250.24(5) If I understand the OP and I see where Ken (480 Sparky) made a point as well.

 

[John Valdes]

Am I missing something? I thought a 4 wire feeder was required in NEC 2008? Does 2008 abolish the conduit as ground? Thanks

 

[infinity]

Am I missing something? I thought a 4 wire feeder was required in NEC 2008? Does 2008 abolish the conduit as ground? Thanks

The answer is no if it qualifies as an EGC under article 250.

 

[Dennis Alwon]

Is a ground wire required to be provided from a distribution panel feeding a sub panel?

It all depends on what the op is asking. What is a ground wire? Does he/she mean grounded or grounding? Are we talking about a panel to another building, etc....