EGC wire and metal boxes

[crossman]

the real question is still the interpretation of
connecting the ground wire "to" the box, and on that
question I believe a reasonable interpretation is that
it doesn't include the path back to the panel, bus
and back through the EMT.

I can appreciate your interpretation. Thank you.

But to me, if the EGC wire is connected to the box via equipment listed for grounding, then we are okay by code. I guess I am being redundant now.

 

[rexowner]

I can appreciate your interpretation. Thank you.

But to me, if the EGC wire is connected to the box via equipment listed for grounding, then we are okay by code. I guess I am being redundant now.

Thanks for the discussion. I made me re-read and
think about this.

The ironic thing is that I shared your interpretation in
the past. Don't tell anyone, but I sometimes installed
metal boxes grounded by EMT where the spliced EGC wire
wasn't e.g. connected via a ground screw or clip. After
reading this thread, I think I was wrong in the past.

 

[crossman]

The ironic thing is that I shared your interpretation in
the past. Don't tell anyone, but I sometimes installed
metal boxes grounded by EMT where the spliced EGC wire
wasn't e.g. connected via a ground screw or clip. After
reading this thread, I think I was wrong in the past.

Doh! After all my impecable logic, and you go the other way?:-?

:wink:

 

[crossman]

"since the installer has opted not to rely on the raceway as an equipment ground, then I will not consider it as an equipment ground". In this case the AHJ may treat it just as if the EMT was replaced with PVC; the wire equipment ground becomes the only reliable equipment ground and must be installed accordingly.

250-118 disagrees with you wholeheartedly.

"The equipment grounding conductor run with or enclosing the circuit conductors shall be one or more or a combination of the following"

I personally don't think it is proper for the AHJ to require an installation to meet non-existent code rules unless there are ordinances to back it up.

"since the installer has opted not to rely on the raceway as an equipment ground, then I will not consider it as an equipment ground".

It would be making an assumption that the installer is no longer relying on the EMT as an EGC. Just because a green wire is installed, it does not negate using the EMT as one or more or a combination of the following.

This whole thing could be turned around and an AHJ could say:

Since the installer has opted not to rely on the wire-type equipment ground as an equipment ground, and is using EMT instead, then I will not consider the wire as an equipment ground". In this case the AHJ may treat it just as if the Equipment Grounding conductor did not exist; the EMT becomes the only reliable equipment ground and must be installed accordingly.

 

[M. D.]

I can appreciate your interpretation. Thank you.

But to me, if the EGC wire is connected to the box via equipment listed for grounding, then we are okay by code. I guess I am being redundant now.

I have been thinking ,.. what if you had several wire type equipment grounding conductors ,..and they are required to be joined together ,
Would you argue that they are because they terminate on the same grounding bar in the panel ??

The reason they want them to be joined , as described, is to create a web of grounding conductors so as to make a path with very low impedance during a fault on any one of the ungrounded conductors.

I think it is clear ,..The Emt is connected to the box , that is one EGC , the wire is a second EGC and it is not. I would write it up.

I like the way you think though.

 

[crossman]

I have been thinking ,.. what if you had several wire type equipment grounding conductors ,..and they are required to be joined together

Can you give me a scenario on this one? Of course, we won't even talk about the possible literal violations of 310.4.

Would you argue that they are because they terminate on the same grounding bar in the panel ??

Possibly. Depends on the circumstance.

The reason they want them to be joined , as described, is to create a web of grounding conductors so as to make a path with very low impedance during a fault on any one of the ungrounded conductors.

Then why don't they require the wire-type EGC to be terminated to the metal box, within the box, under all circumstances?

I think it is clear ,..The Emt is connected to the box , that is one EGC , the wire is a second EGC and it is not. I would write it up.

The wire EGC is connected to the box with equipment listed for grounding, therefore the code is satisfied.

I like the way you think though.

Thank you! It is fun to argue these types of things.

 

[cowboyjwc]

Now, while I may believe that you are correct in your thinking and as an install this may be perfectly fine, and you may be right that a wording change, or changes, could clear it up, I always remind people that 90.4 is in the code book for a reason.

 

[crossman]

Now, while I may believe that you are correct in your thinking and as an install this may be perfectly fine, and you may be right that a wording change, or changes, could clear it up,

I appreciate that.

I always remind people that 90.4 is in the code book for a reason.

Agreed. Of course, there is 90.6 also. But bringing 90.4 into it pretty much negates every argument about the code that has ever been on this forum. How many threads have we seen about an inspector and his oddball understanding or misunderstanding or ignorance of the code?

With 90.4, basically we are saying "the inspector is always right" and what the code says doesn't matter?

 

[dcspector]

With 90.4, basically we are saying "the inspector is always right" and what the code says doesn't matter?

I disagree. Back to topic. Education is the key for all. If one breaks the CCC's in a box then one has a potential voltage difference.

 

[crossman]

I disagree. Back to topic. Education is the key for all.

I appreciate that.

If one breaks the CCC's in a box then one has a potential voltage difference.

I would say that a potential difference exists between the CCCs anytime the breaker is on, whether the CCCs are broken or not.

I am not arguing what the CMP intended, I am not arguing what the AHJ might interpret, I am arguing what the NEC 2008 versions says.

 

[M. D.]

Can you give me a scenario on this one? Of course, we won't even talk about the possible literal violations of 310.4.

250.148 , there are many times when more than one EGC from different circuits are required to be spliced together. Not sure 310.4 pertains ,..they want the grounding conductors joined , when the un grounded are spliced or terminated within the box.

Then why don't they require the wire-type EGC to be terminated to the metal box, within the box, under all circumstances?

When don't they ,.. excepting 250 146(D)

The wire EGC is connected to the box with equipment listed for grounding, therefore the code is satisfied.

no,.. it is connected to the grounding bus in the panel there is no connection within or to the box

Thank you! It is fun to argue these types of things.

yes it is,.. I had a good go-round on bonding all metal parts recently

 

[crossman]

Originally Posted by crossman
Then why don't they require the wire-type EGC to be terminated to the metal box, within the box, under all circumstances?

When don't they ,.. excepting 250 146(D)

If the circuit conductors are not spliced or terminated in the box, the EGC wire can go right through without being attached within the box. To me, that seems strange.

Originally Posted by crossman
The wire EGC is connected to the box with equipment listed for grounding, therefore the code is satisfied.

no,.. it is connected to the grounding bus in the panel there is no connection within or to the box

There is certainly a connection to the box via equipment listed for grounding. This is allowed by the wording that was added to the 2008 NEC in 250.148(C).


Now, perhaps the code panel messed up and went with language that was much too broad in the 2008 code. But that doesn't matter. The code says that the EGC wire can be terminated to the box using equipment listed for grounding. EMT and fittings meets that requirement.

 

[frizbeedog]

Now, perhaps the code panel messed up and went with language that was much too broad in the 2008 code. But that doesn't matter. The code says that the EGC wire can be terminated to the box using equipment listed for grounding. EMT and fittings meets that requirement.

Does anyone here know someone personnally on Code-Making Panel #5 ?

I notice all their names are listed in the front of the codebook. I think one or more of them needs to receive an e-mail with a link to this thread.

Because after reading all the arguments I think crossman (Gene) may have something. However, I don't think he has persuaded me to change my interpration of what was intended. No need to restate all the arguments.

Let's see if we can put one of them on the spot. :smile:

And get this cleared up.

 

[M. D.]

....Now, perhaps the code panel messed up and went with language that was much too broad in the 2008 code. But that doesn't matter. The code says that the EGC wire can be terminated to the box using equipment listed for grounding. EMT and fittings meets that requirement.

I think it is clear ,I think they understand there will be and, in fact they desire as many grounding paths back as practical, to lower impedance under fault conditions ,.. in your example the wire conductor is not terminated within the box it is terminated at the panel ..

I think you ought to , and we can help , submitt a proposal that would address this concern.

 

[frizbeedog]

Note:

An e-mail has just been dispatched to Mr. Chuck Mello of UL on CMP #5

Surprisingly, those guys e-mail addresses are easy to find.

We'll see what happens. :smile:

.....think I'll try another one. :wink:

 

[76nemo]

Note:

An e-mail has just been dispatched to Mr. Chuck Mello of UL on CMP #5

Surprisingly, those guys e-mail addresses are easy to find.

We'll see what happens. :smile:

.....think I'll try another one. :wink:

crossman has a point, this is all about code and not practice. Can someone show a pic where expansion joints should of been used, but weren't, or EMT pulled apart, and we can leave it there?

 

[frizbeedog]

crossman has a point, this is all about code and not practice. Can someone show a pic where expansion joints should of been used, but weren't, or EMT pulled apart, and we can leave it there?

I'm sure we could. But I'm hip to Gene's wording delima, and I now think we have really exhausted the argument and need something more.

We all know about the flaws, of some conduit installations, and what actions we'd take to avoid that hazard.

But at this point I'll side with Gene and see if we can get some answers. :smile:

Sorry, the koolaide was just too hard to resist. :wink:

....but for the record, I don't agree with him...I think. :-?

He never actually said what he thought his interpratation was. But that's the beauty of an argument.

:smile: :roll:

 

[76nemo]

I'm sure we could. But I'm hip to Gene's wording delima, and I now think we have really exhausted the argument and need something more.

We all know about the flaws, of some conduit installations, and what actions we'd take to avoid that hazard.

But at this point I'll side with Gene and see if we can get some answers. :smile:

Sorry, the koolaide was just too hard to resist. :wink:

....but for the record, I don't agree with him...I think.

He never actually said what he thought his interpratation was. But that's the beauty of an argument.

:smile: :roll:

You S.O.G., are you dipping into my koolaid?:grin:

 

[frizbeedog]

You S.O.G.

Is that akin to S.O.B., only nicer? :smile:

 

[76nemo]

Is that akin to S.O.B., only nicer? :smile:

Son Of a Gun. If you called me a S.O.B., I'd steal your KoolAid:grin: :wink:

I have to finish my KoolAid and retire. All this sugar has got me drowsy:grin:

Good night all. Stay safe!!!!!!!!!!!!!!!