How can I get an official interpretation of a specific NEC section?

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realolman said:
It seems to me that the GEC and the waterpipe .....
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It's no disgrace to be dumb , but it is unhandy as heck... and my 10 minutes are up..... I meant to say EGC everywhere I said GEC... durn it!

Maybe one of the moderators would be kind enough to fix it, so it doesn't throw another knot into the thread.
 
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When you call 800.344.3555 one of the menu options is 'for interpretation'. I have never used that so I can't tell you what is involved in that process.
 
realolman, I know that you were saying GEC when you meant to say EGC, but look back at the original post. Either Electron Sam78 was making the same mistake, or the contractor is actually bringing a GEC along with the feeder.

Just to clarify, I am going to expand out the abbreviations:
GES: Grounding Electrode System
GEC: Grounding Electrode Conductor
EGC: Equipment Grounding Conductor

A building supplied with a feeder must have a grounding electrode system. But I don't see any requirement as to _where_ that grounding electrode system is, and no requirement that prevents a single grounding electrode system from serving multiple buildings. So if they are actually running something that meets _all_ of the requirements for a grounding electrode conductor, then it seems to me that the main building GES could be used as the detached structure GES.

They are also required to run an EGC with the feeder. An open question is if the EGC can also serve as the GEC. It seems to me that if you meet all of the requirements for both, then this is possible...though simultaneously meeting the requirement that the EGC run with the circuit conductors _and_ the GEC be unspliced would be difficult. Probably more difficult than sinking a couple of ground rods.

On top of this, no matter what hoops you jump in order to use some remote grounding electrodes, you are also required to use _all_ available grounding electrodes. If there is metal underground water pipe, you _must_ use it as part of your grounding electrode system. If there is concrete encased electrode, you must use it.

Finally, and separate from all grounding issues, if there is internal metal water piping, it _must_ be bonded, even if there is no underground metallic portion.

Now, given the actual utility of grounding, if they were to bond the water piping and run an EGC with the feeder, I wouldn't stress too much. But if they are trying to cut corners here I'd wonder what other corners were being cut.

-Jon
 
winnie said:
Either Electron Sam78 was making the same mistake, or the contractor is actually bringing a GEC along with the feeder.

Just to clarify, I am going to expand out the abbreviations:
GES: Grounding Electrode System
GEC: Grounding Electrode Conductor
EGC: Equipment Grounding Conductor

-Jon
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yep I meant to say EGC in the OP where I said GEC
 
winnie said:
realolman, I know that you were saying GEC when you meant to say EGC,
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thanks Winnie... my mistake didn't sink in until after the edit time was past

winnie said:
.......
A building supplied with a feeder must have a grounding electrode system. But I don't see any requirement as to _where_ that grounding electrode system is, and no requirement that prevents a single grounding electrode system from serving multiple buildings. So if they are actually running something that meets _all_ of the requirements for a grounding electrode conductor, then it seems to me that the main building GES could be used as the detached structure GES.

They are also required to run an EGC with the feeder. An open question is if the EGC can also serve as the GEC. It seems to me that if you meet all of the requirements for both, then this is possible...though simultaneously meeting the requirement that the EGC run with the circuit conductors _and_ the GEC be unspliced would be difficult. Probably more difficult than sinking a couple of ground rods.

On top of this, no matter what hoops you jump in order to use some remote grounding electrodes, you are also required to use _all_ available grounding electrodes. If there is metal underground water pipe, you _must_ use it as part of your grounding electrode system. If there is concrete encased electrode, you must use it.

Finally, and separate from all grounding issues, if there is internal metal water piping, it _must_ be bonded, even if there is no underground metallic portion.

Now, given the actual utility of grounding, if they were to bond the water piping and run an EGC with the feeder, I wouldn't stress too much. But if they are trying to cut corners here I'd wonder what other corners were being cut.

-Jon
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My question was very similar to what you are saying... I got the impression that there was an underground metallic water pipe serving the new building. Maybe I was wrong about that. But if there is... Roger correctly pointed out that you still need a supplemental grounding electrode.

The thing is , 250.54 seems to exclude supplemental electrodes from conforming to everything a "normal" electrode needs, and even seems allow it to be connected to the Equipment Grounding Conductor .... maybe back at the main service???

Could the fact that they're running an Equipment Grounding Conductor, and have metallic water pipes (which they are going to bond ) serving the new building, make the use of the original grounding electrode, connected to the Equipment Grounding Conductor back at the original service, be O K as the supplemental grounding electrode....... whew!:)
 
Would a Mike Holt graphic that clearly shows the requirement help?
I can email one to you if you pm me with your email address.
 
Well I filled out the FI request form on my computer and emailed it to the NFPA. I just got a reply from the Secretary saying it was forwarded to the electrical department.

I worded the question like this: "Does a building located remotely from the service equipment and fed by a single phase, 4-wire supply (not from a service disconnecting means but from a load side over-current protective device (OCPD)) to a main breaker panelboard at the remote building need a grounding electrode system installed in or at the remote building or structure even if an equipment grounding conductor is run to the remote building with the supply conductors?"
 
Wow I already got a response yesterday from the NFPA. They said they can't give an official ruling because they believe the text of the section is too clear and decisive for there to be any doubt in its meaning. But the NFPA Senior Electrical Engineer gave me his personal opinion confirming that there needs to be a ground rod at the site of the feeder supplied building or structure and that the supply conductors as I describe them are in fact feeders and not a branch circuit. Now I'll forward all this info to the responsible parties and hope they have a backbone.
 
Electron_Sam78 said:
Wow I already got a response yesterday from the NFPA. They said they can't give an official ruling because they believe the text of the section is too clear and decisive for there to be any doubt in its meaning. But the NFPA Senior Electrical Engineer gave me his personal opinion confirming that there needs to be a ground rod at the site of the feeder supplied building or structure and that the supply conductors as I describe them are in fact feeders and not a branch circuit. Now I'll forward all this info to the responsible parties and hope they have a backbone.
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They will... they'll fire you :)
 
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