Please explain

[bwat]

NEC calls those same three conductors "ungrounded conductor, grounded conductor and equipment grounding conductor". To someone not familiar or too lazy to look at the definitions this can be confusing - all three of them have "ground" within them.

Sure they all have the word ground in them, but the way the word is used makes sense for the others. So I'd like to suggest that it can be confusing for even the people who aren't too lazy to look up the definitions. Once they look up the definitions, they all make sense based on the name.. except for one.

Ungrounded Conductor... the conductor isn't grounded...✔
Grounded Conductor... the conductor is grounded...✔
Equipment Grounding Conductor... hmmm...

And for the person that looks up the definitions you also have these NEC definitions which you then try to line up with EGC name:

Ground. The earth.

Grounded (Grounding). Connected (connecting) to ground or to a conductive body that extends the ground connection.

But in all those cases NEC is still consistent with using those words within it's own definitions, which is the first key to understanding all of this

Yes, they have definitely gotten better with it over the years. I don't think it was too long ago though that there was something similar to a requirement to "ground" receptacles or switches or other similar devices IIRC. Something like that. Anyone recall? And I believe there are still a few other remnants in there that require us to "ground" something when I'm pretty sure they don't mean connect it to the earth as the Dirt Worshipers (credit to Dave) would like to think.

 

[winnie]

"zero point referenced circuit conductor"
"elevated potential circuit conductor"
"potential equalization conductor not intentionally part of a circuit"
"ambient terrain reference galvanic coupling element"
"ambient terrain reference conductor"
"zero point referenced circuit conductor to ambient terrain reference conductor connection thingie"

There, that clears it all up

 

[bwat]

"zero point referenced circuit conductor to ambient terrain reference conductor connection thingie"

I had a legitimate LOL on this one

 

[PaulMmn]

Ungrounded Conductor... the conductor isn't grounded...✔
Grounded Conductor... the conductor is grounded...✔
Equipment Grounding Conductor... hmmm...

Equipment Bonding Conductor...
Protective Bonding Conductor...
Emergency Bonding Conductor...

On another note-- we shouldn't use "zero point" in any definition-- once zero-point energy sources become real, that would just add more confusion!

 

[ActionDave]

I use zero point all the time when talking about voltage reference to ground.

 

[PaulMmn]

I use zero point all the time when talking about voltage reference to ground.

Sorry about the confusion-- but Zero-point energy in science fiction terms is basically 'free energy' from the universe around us.

 

[jaggedben]

Late to this thread. Man, what a mess. So much for 100 words.

Bonding brings the various exposed metal parts of an installation to the same potential so there's not a voltage gradient between them that could produce a shock.

Grounding provides a path for faults to follow to provide sufficient current to flow and open the OCD.

This, in my opinion, gets it exactly backwards. Try this. (Note that grounding doesn't just apply to exposed metal parts, we ground current carrying coductors, too.)

Grounding brings the various exposed metal parts of an installation to the same potential as the earth so there's not a voltage gradient between them that could produce a shock.

Bonding provides a path for faults to follow to provide sufficient current to flow and open the OCD.

Compare to the NEC definitions, which ... why didn't we all just start there?

Bonded (Bonding). Connected to establish electrical continuity and conductivity.
Grounded (Grounding). Connected (connecting) to ground or to a conductive body that extends the ground connection.

As for Equipment Grounding Conductors, they provide both, but only when a main (or system) bonding jumper is installed along with proper grounding. If the main bond isn't provided then the EGC only grounds. If a grounding electrode connection isn't provided then the EGC only bonds.

 

[kwired]

Art 250, Grounding and bonding.

Title alone probably makes some believe they are the same thing.

There is still definitions for specific terminology as used in the document.

 

[LarryFine]

Art 250, Grounding and bonding.

Title alone probably makes some believe they are the same thing.

How about: "Art 250, Grounding and/or bonding."?

 

[kwired]

How about: "Art 250, Grounding and/or bonding."?

IDK. I still think bigger problem is not understanding the function as well as the potential consequences if not doing it right. Can name things whatever you want and there will still be some confusion.

I thing the fact we use grounded conductors as current carrying circuit conductors doesn't help either which makes it easy to bootleg grounded/grounding conductors at times and if you don't know the reasons why you shouldn't do that you get false feeling of it works, must be ok..

 

[Carl Johnson]

NEC Article 250.4(A)(1) through 250.4(A)(5) does a precise job of explaining why we ground and why we bond. Suggest also becoming familiar with the terms in Article 100.
For me it took several (or more) careful reads to grasp the concepts. Mike's training materials will also add to clarify the issue.