250.32

[gator07]

Would a 4x4 post with a small 100 amp panal on it be considered a seperate structure, and require two ground rods . I believe so but its not enforced in my neck of the woods! just want to know for my own good.

 

[roger]

Would a 4x4 post with a small 100 amp panal on it be considered a seperate structure, and require two ground rods . I believe so but its not enforced in my neck of the woods! just want to know for my own good.

Using the definition

Structure. That which is built or constructed.you

you would be correct, if that is really the intent, I don't know.

Roger

 

[jim dungar]

Would a 4x4 post with a small 100 amp panal on it be considered a seperate structure, and require two ground rods . I believe so but its not enforced in my neck of the woods! just want to know for my own good.

In my opinion it is up to the building department/inspector to determine if it is a structure.

 

[don_resqcapt19]

In my opinion it is up to the building department/inspector to determine if it is a structure.

Jim,
The term is defined in the NEC so the only definition that you can use for the application of the NEC is the one found in Article 100. You can't look to other documents or codes for definition of terms found in Article 100.

Scope. This article contains only those definitions essential to the proper application of this Code. It is not intended to include commonly defined general terms or commonly defined technical terms from related codes and standards. In general, only those terms that are used in two or more articles are defined in Article 100. Other definitions are included in the article in which they are used but may be referenced in Article 100. ... Structure. That which is built or constructed.

 

[M. D.]

I don't think the AHJ can determine this to be something other than a structure ,.. grounding electrode or grounding electrode system required

http://www.necplus.org/Lists/CodeTopic/DispForm.aspx?ID=41

Originally this question was published in NECdiegest

As a side note ,.Sargent was the senior Editor of the 2005 Handbook.

necdigest?, August 2007

Compiled by Jeff Sargent and the NFPA Electrical Engineering Team

......but the questionable call here is whether the posts that the pool panel is mounted to are considered to be a structure.

The NEC defines a structure as ?that which is built or constructed.? Based on this definition, a frame constructed for the purposes of supporting and mounting outdoor electrical equipment is a structure and, as such, is subject to the applicable requirements in the NEC covering feeders and branch circuits installed at that structure. A feeder disconnecting means is required at this structure.......

 

[M. D.]

In my opinion it is up to the building department/inspector to determine if it is a structure.

I do believe in the State of Wisconsin they have deleted the definition of structure,... However the building code definition is said to be the same as the 2008 NEC definition for the same term,. About 3/4 of the way down the page.. it would not allow cut and paste.

http://www.commerce.state.wi.us/sb/SB-CodeCouncilsElecSumm.html

 

[jrannis]

In Miami-Dade County they consider a generator pad an auxillary structure and has to have a ufer ground/ ground rod and comply with zoning setbacks as if it were a building

 

[tryinghard]

Would a 4x4 post with a small 100 amp panal on it be considered a seperate structure, and require two ground rods . I believe so but its not enforced in my neck of the woods! just want to know for my own good.

It really should be grounded otherwise the feeding or destination will be the first connection to earth, see 250.4(A)(1).

 

[jim dungar]

I do believe in the State of Wisconsin they have deleted the definition of structure,... However the building code definition is said to be the same as the 2008 NEC definition for the same term,. About 3/4 of the way down the page.. it would not allow cut and paste.

http://www.commerce.state.wi.us/sb/SB-CodeCouncilsElecSumm.html

According to the local inspector (on a site this morning) a 4X4 post is not considered a structure in Wisconsin.

 

[Dennis Alwon]

According to the local inspector (on a site this morning) a 4X4 post is not considered a structure in Wisconsin.

So are they saying that only 3 wires are required in this scenario????

 

[jim dungar]

So are they saying that only 3 wires are required in this scenario????

The electical installation was not discussed.

 

[LarryFine]

So are they saying that only 3 wires are required in this scenario????

If a disconnect is present, it's still where the 4-wire cabling should begin.

 

[Dennis Alwon]

If a disconnect is present, it's still where the 4-wire cabling should begin.

I agree but does the code address a non structure. From the 4x4 to a building the code addresses but to nowhere land????.

I am sure the intent of the code is for a 4 wire to anything but who knows.

 

[gator07]

So for example a 4 wire feeder, feeding a sub panal on a post that feeds a mobile home would require 2 ground rods? sorry a little confused!

 

[Dennis Alwon]

So for example a 4 wire feeder, feeding a sub panal on a post that feeds a mobile home would require 2 ground rods? sorry a little confused!

It may be good to read 250.32 (A). The question, of course, is whether a 4x4 is a structure.

Here is the definition of structure

Structure. That which is built or constructed.

That is all we have to go by.

 

[wbalsam1]

IMHO, a 4X4 or 6X6 or two 4X4's or 6X6's planted in the ground and having electrical equipment mounted on it (them) constitutes a "structure". The wooden structural member has structural integrity sufficient to carry the eccentric loads imposed on it by the NEMA 3-R panel and any required metering enclosure. It also provides a means to fasten conduits that emerge from the ground, etc.
To me, it's clear that the code intends these to be called structures. :smile: