inspector joe

[inspectorjoe]

the question is: many AHJ's require a ground rod at the base of the concrete ballards. (for lighting poles) is this what we would call a supplemental requirement or just local ordinance? what is the code reference for this. are we calling the concrete a structure? for which the light is being mounted on?

 

[user 100]

the question is: many AHJ's require a ground rod at the base of the concrete ballards. is this what we would call a supplemental requirement or just local ordinance? what is the code reference for this. are we calling the concrete a structure? for which the light is being mounted on?

See 250.32 (A).....

With that said, Im not sure in this instance- I mean, a pole is considered a structure. Much brighter minds here will have to interject about the technical definitions/interpretations of a structure.

A reliable egc is far more important than pounding a rod, and on top of that, the rebar in the sidewalk would make a better GE than a rod anyway.

 

[infinity]

the question is: many AHJ's require a ground rod at the base of the concrete ballards. (for lighting poles) is this what we would call a supplemental requirement or just local ordinance? what is the code reference for this. are we calling the concrete a structure? for which the light is being mounted on?

It would be an auxiliary electrode not a supplemental electrode according to the NEC. You can install as many auxiliary electrodes as you like or none at all.

 

[cowboyjwc]

I don't require one, but I see it a lot when the engineers are from the Midwest.

 

[electrofelon]

See 250.32 (A).....

With that said, Im not sure in this instance- I mean, a pole is considered a structure. Much brighter minds here will have to interject about the technical definitions/interpretations of a structure.

A reliable egc is far more important than pounding a rod, and on top of that, the rebar in the sidewalk would make a better GE than a rod anyway.

Even if it is a structure, there is still not a GE required unless it is supplied by a feeder.

 

[kwired]

:thumbsup::thumbsup::thumbsup:

bingo

Even if it is a structure, there is still not a GE required unless it is supplied by a feeder.

and if you put one there it is simply a supplemental electrode.

If you have under 25 foot pole, you might not have much of a base, but base still is likely a better electrode then a single rod. If you have 100 foot tall pole - your base is definitely a better electrode then a single rod.

The "dirt worshipers" have been mentioned recently in a few other threads.

 

[infinity]

:thumbsup::thumbsup::thumbsup:

bingo



and if you put one there it is simply a supplemental electrode.

Supplemental or auxiliary?

 

[kwired]

Supplemental or auxiliary?

Auxiliary is probably the correct term.:ashamed1:

 

[user 100]

Even if it is a structure, there is still not a GE required unless it is supplied by a feeder.

It would be an auxiliary electrode not a supplemental electrode according to the NEC. You can install as many auxiliary electrodes as you like or none at all.

:slaphead::slaphead:

I see it now..... was thinking about something else entirely.:dunce:

OP: these auxiliary electrodes referenced by Infinity are listed in 250.54, and no, they are not required, just permitted- and disregard my original post a few replies above.

The "dirt worshipers" have been mentioned recently in a few other threads.

The dirt worshipers can be squashed with this:

(1)Get one of them to the disconnect the GEC from a rod, and then create a deliberate dead short to the rod with a hot run straight from a breaker in the panel- they will see the breaker won't trip and there is now 120v on that rod.

(2)Then get them to do the same thing with the hot touching a tail from the ground bar or noodle bus- they see breaker opens instantly, 120v on nothing...

(3)Then ask them again about the effectiveness of a rod when it comes to clearing a fault.

The old golden rule about current always trying to return to its source is proven physics, and why they think fault current is different and would need a less than optimum path is beyond me.

 

[Smart $]

...
The dirt worshipers can be squashed with this:

(1)Get one of them to the disconnect the GEC from a rod, and then create a deliberate dead short to the rod with a hot run straight from a breaker in the panel- they will see the breaker won't trip and there is now 120v on that rod.

(2)Then get them to do the same thing with the hot touching a tail from the ground bar or noodle bus- they see breaker opens instantly, 120v on nothing...

(3)Then ask them again about the effectiveness of a rod when it comes to clearing a fault.

The old golden rule about current always trying to return to its source is proven physics, and why they think fault current is different and would need a less than optimum path is beyond me.

Please have them don the proper PPE first. :happyyes:

 

[steve66]

I don't require one, but I see it a lot when the engineers are from the Midwest.

Guilty as charged.

Even if it is a structure, there is still not a GE required unless it is supplied by a feeder.

I don't see that. 250.32(A) says "feeder or branch circuit(s)...." What am I missing?

Auxiliary is probably the correct term.:ashamed1:

I don't see that either.

I have no doubt a ground rod does nothing, but I always thought it is required by code.

 

[kwired]

Guilty as charged.



I don't see that. 250.32(A) says "feeder or branch circuit(s)...." What am I missing?



I don't see that either.

I have no doubt a ground rod does nothing, but I always thought it is required by code.

Read the exception that follows 250.30(A)

 

[oldsparky52]

HELP

HELP

Read the exception that follows 250.30(A)

I'm confused, I thought we were talking about referencing the circuit bonding conductor to ground at light poles. Isn't that exception talking about referencing a neutral conductor?

 

[kwired]

I'm confused, I thought we were talking about referencing the circuit bonding conductor to ground at light poles. Isn't that exception talking about referencing a neutral conductor?

NEC wants a grounding electrode system at each structure, the exception is saying if the structure is supplied by a branch circuit this is not necessary. It does go on to say there must be an equipment grounding conductor - but that is required elsewhere anyway.

Again reality is that most concrete base poles already have better electrode in the base itself then a single rod will provide.

 

[oldsparky52]

NEC wants a grounding electrode system at each structure, the exception is saying if the structure is supplied by a branch circuit this is not necessary. It does go on to say there must be an equipment grounding conductor - but that is required elsewhere anyway.

Again reality is that most concrete base poles already have better electrode in the base itself then a single rod will provide.

I'm not arguing against what you posted other than I don't understand why you mentioned the exception you did when it seems to be addressing something different than what the discussion was about.

 

[kwired]

I honestly feel contents of 250.32 probably should be in part III instead of part II, and that is maybe what your confusion is based on as well?

 

[electrofelon]

NEC wants a grounding electrode system at each structure, the exception is saying if the structure is supplied by a branch circuit this is not necessary. It does go on to say there must be an equipment grounding conductor - but that is required elsewhere anyway.

Again reality is that most concrete base poles already have better electrode in the base itself then a single rod will provide.

Yeah its frustrating two fold: first is just the over emphasis on dirting things thinking it will do a bunch of good, and second is putting in a rod when the thing itself is already dirted. My rant on the fence grounding in the grounding v bonding section is a prime example. Fine, you want an electrode at the lamp post, let us just grab the rebar in the base...