GEC entering panel

[MAC702]

from 250.64(E)(1)...

That doesn't address what I asked. You quoted a 97% choke on GEC entry through a 1/4" KO, and generically cited UL and EE literature. I directly quoted you for this and asked you for a specific citation that we can review.

 

[romex jockey]

That doesn't address what I asked. You quoted a 97% choke on GEC entry through a 1/4" KO, and generically cited UL and EE literature. I directly quoted you for this and asked you for a specific citation that we can review.

???

What i did do quote Mike Holt, who in an EC&M article writes the following>

The NEC has long required that ferrous metal raceways containing the GEC be bonded at each end to reduce the effects of "inductive choke" on the conductors. The Code now includes more specifics on how to do this. The bonding method must be in compliance with 250.92(B) at service equipment locations. For other than service equipment locations, 250.92(B)(2) through (B)(4) must be followed to meet this requirement [250.64(E)].

Nonferrous metal raceways, such as aluminum rigid metal conduit, enclosing the GEC are not required to meet the "bonding each end of the raceway to the GEC" provisions of this section.The effectiveness of a grounding electrode is significantly reduced if a ferrous metal raceway containing a GEC isn't bonded to the GEC at each end. This is because a single conductor carrying high-frequency induced lightning current in a ferrous raceway causes the raceway to act as an inductor. That severely limits (chokes) the current flow through the GEC. ANSI/IEEE 142, "Recommended Practice for Grounding of Industrial and Commercial Power Systems" (Green Book) states: "An inductive choke can reduce the current flow by 97%."

article

~CS~

 

[MAC702]

???

What i did do quote Mike Holt, who in an EC&M article writes the following

The NEC has long required that ferrous metal raceways containing the GEC be bonded at each end to reduce the effects of "inductive choke" on the conductors. The Code now includes more specifics on how to do this. The bonding method must be in compliance with 250.92(B) at service equipment locations. For other than service equipment locations, 250.92(B)(2) through (B)(4) must be followed to meet this requirement [250.64(E)].

Nonferrous metal raceways, such as aluminum rigid metal conduit, enclosing the GEC are not required to meet the "bonding each end of the raceway to the GEC" provisions of this section.The effectiveness of a grounding electrode is significantly reduced if a ferrous metal raceway containing a GEC isn't bonded to the GEC at each end. This is because a single conductor carrying high-frequency induced lightning current in a ferrous raceway causes the raceway to act as an inductor. That severely limits (chokes) the current flow through the GEC. ANSI/IEEE 142, "Recommended Practice for Grounding of Industrial and Commercial Power Systems" (Green Book) states: "An inductive choke can reduce the current flow by 97%."

Okay, now we can discuss your claim.

You've taken a source that describes ferrous raceways that also mentions how an inductive choke can reduce current flow 97%, and then said

...Given i've run many a GEC thru a 1/4" hole, one can imagine the choke effect (as stated in UL & EE level literature) 97% ...

Do you understand the confusion?

Are you really worried that not buying Kenny's clamps is causing a 97% choke in your GEC and no one's ever noticed before?

 

[roger]

There is the GEC entry, and the GEC termination

Yes there is that's not in question.

the codes addresses the 'entry' as 'listed fitting' in 250.8

This is where you keep floundering Steve, 250.8 is only addressing connections of the conductor be it the EGC, GEC, MBJ, SSBJ, to the equipment with an approved method, it is not about an entry, if you will read it without bias you will see it.

The connections can be lugs, welds, bars, pressure connectors, bolts, etc... inside or outside the equipment but it doesn't care or address how the conductor gets into the equipment.

Roger

 

[romex jockey]

Yes there is that's not in question.

This is where you keep floundering Steve, 250.8 is only addressing connections of the conductor be it the EGC, GEC, MBJ, SSBJ, to the equipment with an approved method, it is not about an entry, if you will read it without bias you will see it.

The connections can be lugs, welds, bars, pressure connectors, bolts, etc... inside or outside the equipment but it doesn't care or address how the conductor gets into the equipment.

Roger

I beg to differ as 250.64 (E) (1) reads>>>>

from the point of attachment to cabinets or equipment

and>>>

bonded at each end of the raceway or enclosure to the
grounding electrode or grounding electrode conductor to
create an electrically parallel path.

Meaning if the 'entry' is unbonded, there can be no 'electrically parallel path' which is the intent of the code no matter how long or short the ferrous material is

~RJ~

 

[MAC702]

I'm a certified IAEI inspector...

When it comes to issues like this, is the inspector the one making the call, or someone higher up in the AHJ? Do all of the inspectors working for your AHJ have the same interpretation?

Are you currently requiring contractors to install Kenny clamps? Are the other inspectors?

 

[romex jockey]

Okay, now we can discuss your claim.

You've taken a source that describes ferrous raceways that also mentions how an inductive choke can reduce current flow 97%, and then said


Do you understand the confusion?

Yes , and the code does not discriminate between a raceway and enclosure , nor does it specifically state any length , diameter , or other specifics that 'ferrous metal'

Note that Mike H, in part 2 of 3 writes>>>

The removal from Art. 100 of the term “grounding conductor” also had an effect in 250.8(A), which now makes it clear that its conductor termination requirements apply to bonding jumpers, equipment grounding conductors, and grounding electrode conductors.

Also note he was opining on '11 changes in this article

I guess few paid attention.....

~RJ~

 

[tom baker]

At the 75th anniversary meeting of the IAEI (2002?) I was at the Kenny Clamp booth, also there was Mike Holt and Phil Simmons (author of Soares Book on Grounding). The Kenny Clamp was new then, I asked Phil if he felt it could be required to be used. He said not likely. Now Mike, for a couple of code cycles, he showed the Kenny Clamp on his grounding graphics.

 

[romex jockey]

When it comes to issues like this, is the inspector the one making the call, or someone higher up in the AHJ? Do all of the inspectors working for your AHJ have the same interpretation?

Are you currently requiring contractors to install Kenny clamps? Are the other inspectors?

I said i held a certification that puts me on par with the better AHJ's (JMHO)

I did not say i was an AHJ

IF, you wish, the NFPA can be solicited for a formal interpretation , most likely Jeff Sargent or similar icon will accommodate your query


good luck

~RJ~

 

[romex jockey]

At the 75th anniversary meeting of the IAEI (2002?) I was at the Kenny Clamp booth, also there was Mike Holt and Phil Simmons (author of Soares Book on Grounding). The Kenny Clamp was new then, I asked Phil if he felt it could be required to be used. He said not likely. Now Mike, for a couple of code cycles, he showed the Kenny Clamp on his grounding graphics.

Interesting & thanks Tom

However ,it must be pointed out 250.8 changed in the '11 cycle

perhaps the graphics followed suit?

~RJ~

 

[roger]

I beg to differ as 250.64 (E) (1) reads>>>>




from the point of attachment to cabinets or equipment




bonded at each end of the raceway or enclosure to the
grounding electrode or grounding electrode conductor to
create an electrically parallel path.

And that is not about the GEC itself, it's about a raceway.

Meaning if the 'entry' is unbonded, there can be no 'electrically parallel path' which is the intent of the code no matter how long or short the ferrous material is


~RJ~

If after the GEC and MBJ are landed the entry is not bonded the enclosure itself must be shredded.

Roger

 

[romex jockey]

shredded.....??

~RJ~

 

[romex jockey]

Conversely , i have been shown manufacturers 1/4" KO's as a GEC entry

But i haven't been shown where they are 'listed' to have such entries forgo 300.15 via 250.8 (A) (8)

~RJ~

 

[MAC702]

Yes , and the code does not discriminate between a raceway and enclosure , nor does it specifically state any length , diameter , or other specifics that 'ferrous metal' ...

So it's okay to take another source about inductive chokes in general and how they can choke up to 97% of current, and then state that number in direct reference to GECs entering a 1/4" KO?

Do you see that that's what that looked like? It makes one question your motives for your position on the subject.

 

[MAC702]

... Kenny Clamp booth, also there was Mike Holt ... Now Mike, for a couple of code cycles, he showed the Kenny Clamp on his grounding graphics.

Mike Holt also has a habit of showing other things that are not required or applicable, some just for humor. Has he expressed an actual opinion about the possible required usage of these clamps, or just illustrated that they can be used? After all, I don't see any reason why they would be bad.

 

[MAC702]

We are talking about a GEC. ... They get sleeved in PVC all the time to keep from having to bond the GEC to the raceway.

In reviewing this thread, I came back across this reply to one of my errant posts. It made me think.

As mentioned, GECs are sometimes sleeved in PVC. Even if using a non-ferrous locknut on the PVC connector, we STILL have the KO's steel around the PVC connector that is housing the GEC.

If a Kenny clamp is required for bonding this steel circle around a bare GEC, then bonding is still required even if a PVC connector is also there. Correct?

 

[peter d]

Okay, now we can discuss your claim.

You've taken a source that describes ferrous raceways that also mentions how an inductive choke can reduce current flow 97%, and then said


Do you understand the confusion?

Are you really worried that not buying Kenny's clamps is causing a 97% choke in your GEC and no one's ever noticed before?

Well stated, I don't think anyone believes that a piece of sheetmetal can provide this inductive choke the way a tubular ferrous raceway can. Otherwise the NEC would address it. But it does not, contrary to what has been claimed.

 

[MAC702]

I said i held a certification that puts me on par with the better AHJ's (JMHO)

I did not say i was an AHJ...

In no way did I say you were an AHJ. But, I assumed you were a practicing inspector that worked for an AHJ. My apologies.

 

[macmikeman]

I said i held a certification that puts me on par with the better AHJ's (JMHO)

I did not say i was an AHJ

IF, you wish, the NFPA can be solicited for a formal interpretation , most likely Jeff Sargent or similar icon will accommodate your query


good luck

~RJ~

I can print me one of them up in ten minutes with the software I have on this computer........ Or conversely , I could pay the annual fee to IAEI and get one of the "Official" ones. This is the joke of the century. Shameful actually.

 

[Little Bill]

This is only my opinion!
I think the use of the word "enclosure" may be throwing some off here. I don't think they are referring to a cabinet, box, etc. I'm thinking of something that encloses the conductors. They use the term "enclosure" right along with raceway. A raceway being a complete conduit system. A short piece would be a sleeve. A sleeve could be an enclosure and maybe what they are referring to.
Otherwise, how could you bond both ends of a cabinet, such as a meter base cabinet, or panel cabinet?

With a "sleeve" being an "enclosure" you could and should bond both ends if it is made of ferrous metal.
It makes zero sense to say to bond both ends of a cabinet. Especially since the conductor only enters the cabinet but does not exit it!