2017 Structure

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George Stolz

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Windsor, CO NEC: 2017
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Mmmkay, so if I put a caisson under a pole light do I have a structure or equipment now? If I screw a panel to a post, what do I have?

Are they trying to screw with us at this point, or...?

Structure.jpg
 

al hildenbrand

Senior Member
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Minnesota
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Electrical Contractor, Electrical Consultant, Electrical Engineer
so if I put a caisson under a pole light do I have a structure or equipment now? If I screw a panel to a post, what do I have?

Caisson? One definition says: "a large watertight chamber, open at the bottom from which the water is kept out by air pressure and in which construction work may be carried out under water."

The way our continuing ed here was laid out, if the light pole goes straight into the ground, it is equipment. If the light pole is bolted to a concrete and rebar base, the light pole is still equipment but it is attached to a structure.

If a panel is part of a pedestal that is installed directly into earth, it is equipment. If the panel is attached to a post, then the post is a structure and the panel remains equipment.
 

Dennis Alwon

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Chapel Hill, NC
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My opinion is that they wanted to say that a single piece of equipment not attached to the house is not a structure. Things like generators, septic pumps, a/c, etc. A panel that feeds other equipment would be a structure but the equipment itself would not need ground rods etc.
 

dkidd

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here
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PE
A panel that feeds other equipment would be a structure but the equipment itself would not need ground rods etc.

"A panel that feeds other equipment..." So the panel is equipment, but then you say it is a structure.

It is, and always will be, equipment.
 

Carultch

Senior Member
Location
Massachusetts
Mmmkay, so if I put a caisson under a pole light do I have a structure or equipment now? If I screw a panel to a post, what do I have?

Are they trying to screw with us at this point, or...?

I think what they are trying to do is exclude free-standing frameworks whose only purpose is mounting equipment, and don't actually enclose an interior space with walls and a ceiling, from the definition of a building or structure. By the ordinary definition of a structure, a free-standing framework is a structure, as it is something constructed to support a load. But the point is to not apply building specfic rules to it.
 

mgookin

Senior Member
Location
Fort Myers, FL
I think what they are trying to do is exclude free-standing frameworks whose only purpose is mounting equipment, and don't actually enclose an interior space with walls and a ceiling, from the definition of a building or structure. By the ordinary definition of a structure, a free-standing framework is a structure, as it is something constructed to support a load. But the point is to not apply building specfic rules to it.

So if I build a platform for the HVAC equipment, that platform is a structure, but the HVAC equipment is not part of that structure.
Makes sense.

Mike Holt's graphics person needs to change "build" to "built"
 

George Stolz

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Windsor, CO NEC: 2017
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Let's try to keep it simple on this one fellas, it's a simple concept. I'm not talking about the Tower of Babel, grounding requirements for a swimming pool, structure of sentences in swahili, or the ten different other things that have come up. Knock it off, it's really getting old in multiple threads, and nobody thinks it's cute.

Now, the definition is trying to exclude equipment as "structure" - but my question remains simply, how does this affect normal operations? If I install a pedestal, then I don't need to install a GES, but if I install a panel on a wood post, I do...?
 

Carultch

Senior Member
Location
Massachusetts
So if I build a platform for the HVAC equipment, that platform is a structure, but the HVAC equipment is not part of that structure.
Makes sense.

Mike Holt's graphics person needs to change "build" to "built"

What I assumed was exactly the opposite. That a concrete slab, or an elevated steel framework, or some other structural member assembly whose only purpose is mounting equipment is not a "structure" for NEC purposes. But if you build a house to host equipment, something that people can walk inside, with walls and a roof, it would be.
 

mgookin

Senior Member
Location
Fort Myers, FL
What I assumed was exactly the opposite. That a concrete slab, or an elevated steel framework, or some other structural member assembly whose only purpose is mounting equipment is not a "structure" for NEC purposes. But if you build a house to host equipment, something that people can walk inside, with walls and a roof, it would be.


OK let's back up.
We have a definition of Structure.
When does this definition come into play?
 

kwired

Electron manager
Location
NE Nebraska
My opinion is that they wanted to say that a single piece of equipment not attached to the house is not a structure. Things like generators, septic pumps, a/c, etc. A panel that feeds other equipment would be a structure but the equipment itself would not need ground rods etc.
Before any changes were made most of those items were supplied by a single branch circuit and never required a grounding electrode anyway. Supply them with a feeder though and they possibly did need a grounding electrode.
 

dkidd

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Location
here
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PE
This is the background for the change in the definition:
 

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al hildenbrand

Senior Member
Location
Minnesota
Occupation
Electrical Contractor, Electrical Consultant, Electrical Engineer
Now, the definition is trying to exclude equipment as "structure" - but my question remains simply, how does this affect normal operations? If I install a pedestal, then I don't need to install a GES, but if I install a panel on a wood post, I do...?
George, keeping it simple: Yes, and yes.
 

peter d

Senior Member
Location
New England
I know George wants to keep this simple..but what is the purpose of having a ground rod for a small WP panel mounted on a 4X4 post? :? Lightning protection?
 

al hildenbrand

Senior Member
Location
Minnesota
Occupation
Electrical Contractor, Electrical Consultant, Electrical Engineer
OK let's back up.
We have a definition of Structure.
When does this definition come into play?

Note the thread title. The 2017 NEC Article 100 Definitions has changed the meaning of "Structure". You can read it in DKidd's post featuring the CMP's work.

The definition will go into effect in any one jurisdiction, when that jurisdiction adopts the 2017 NEC into enforcement.
 

al hildenbrand

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Location
Minnesota
Occupation
Electrical Contractor, Electrical Consultant, Electrical Engineer
A panel that feeds other equipment would be a structure but the equipment itself would not need ground rods etc.
I don't think that's correct, Dennis, by this definition.

Consider a self contained pedestal, containing a couple of breakers and wiring going to some motors laying flat on the ground. The pedestal is planted directly into the earth with no other support. As I understand the Definition, what I just described is ONLY equipment.

Now, instead of using a self contained pedestal, plant a 4 x 4 treated wood post in the ground and attach a small panel with a couple breakers and wiring going to the same motors. The panel and the wiring and the motors are equipment, still. The 4 x 4 however, is a structure.
 

peter d

Senior Member
Location
New England
I don't think that's correct, Dennis, by this definition.

Consider a self contained pedestal, containing a couple of breakers and wiring going to some motors laying flat on the ground. The pedestal is planted directly into the earth with no other support. As I understand the Definition, what I just described is ONLY equipment.

Now, instead of using a self contained pedestal, plant a 4 x 4 treated wood post in the ground and attach a small panel with a couple breakers and wiring going to the same motors. The panel and the wiring and the motors are equipment, still. The 4 x 4 however, is a structure.

This can't be happening, we're in agreement twice in one day. :huh: But that is a good explanation. Still, I'm puzzled by the need for a GES for a panel on a 4X4.
 

kwired

Electron manager
Location
NE Nebraska
I don't think that's correct, Dennis, by this definition.

Consider a self contained pedestal, containing a couple of breakers and wiring going to some motors laying flat on the ground. The pedestal is planted directly into the earth with no other support. As I understand the Definition, what I just described is ONLY equipment.

Now, instead of using a self contained pedestal, plant a 4 x 4 treated wood post in the ground and attach a small panel with a couple breakers and wiring going to the same motors. The panel and the wiring and the motors are equipment, still. The 4 x 4 however, is a structure.

And with the new definition the self contained pedestal wouldn't need a grounding electrode, but the panel on a post will, though the basic functionality is pretty much the same in either case.
 
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