EGC wire and metal boxes

Status
Not open for further replies.
crossman said:
Okay, let's play English Language major...

"A connection shall be made between the one or more equipment grounding conductors and a metal box by means of:

1) a grounding screw that shall be used for no other purpose,
2) equipment listed for grounding,
or
3) a listed grounding device."

So...
Click to expand...
So... playing English Language major, note the listed items are singular. That means you can only accomplish the connection with ONE screw, [piece of] equipment, or device. Note this does not preclude the possibility of making the connection more than once, such as when each of two devices make the connection.

:D :D :D
 
crossman said:
Okay, let's play English Language major and decipher the Code section:

2008 NEC 250.148(C) Metal Boxes - "A connection shall be made between the one or more equipment grounding conductors and a metal box by means of a grounding screw that shall be used for no other purpose, equipment listed for grounding, or a listed grounding device."

Breaking this down based on the or which I highlighted above:

There are three choices listed for grounding the box to the EGC wire. Because of the "or" used with the choices, we only have to use one of the choices to be code compliant. So the code section goes as follows:

"A connection shall be made between the one or more equipment grounding conductors and a metal box by means of:

1) a grounding screw that shall be used for no other purpose,
2) equipment listed for grounding,
or
3) a listed grounding device."

So... 2) equipment listed for grounding can be used for grounding the box. I propose that EMT and fittings are equipment listed for grounding, and the box is indeed connected to the #12 EGC wire through this listed equipment.

The #12 wire is attached to the metal panel enclosure, the box is attached to the panel enclosure via the EMT, so there ya go. I don't see that 250.148 or 250.148(C) require the connection to be made INSIDE the box.

The main part of 250.148 also involves an "or" and gives us an alternative to bonding inside the box... it allows other methods based on 250.148(C).

And the EMT meets that.
Click to expand...



First let me say that in your example, I would be one to say it is a violation as per 250.148 and .148(C).

Your choices 1), 2) are for the method of connecting the Grd conductors to the box.
Lets remember that grounding screws are not a listed product, so they are not part of #2. That is why number 2 exists.
The EMT does not connect the equipement ground conductors within the box to the box.
 
frizbeedog said:
Where in this section 250.148 does it even refer to metal raceways as having anything to do with this? If were going to play english major......

This has nothing to do with type of raceway, or cable or whatever. Read not more into it than is there. Simple.
Click to expand...

Anytime the code says "equipment grounding conductor" then we must look at 250.118 and you will indeed see that EMT is an equipment grounding conductor. So, the EMT raceway in my scenario is directly mentioned in 250.148 wherever it says equipment grounding conductor.
 
Smart $ said:
So... playing English Language major, note the listed items are singular. That means you can only accomplish the connection with ONE screw, [piece of] equipment, or device. Note this does not preclude the possibility of making the connection more than once, such as when each of two devices make the connection.
Click to expand...

Equipment is plural. See article 100 definition of "equipment".

Equipment is "a general term, including material, fittings, devices, appliances, luminaires, apparatus, machinery, and the like used as a part of, or in connection with, an electrical installation."

Material and fittings is definitely plural, and EMT is certainly material, and fittings means gobs and gobs of fittings.:smile:
 
frizbeedog said:
If EMT meets you needs why are you running a grounding conductor? :wink:

Don't install it and you have no more problems.
Click to expand...

You are correct!:)

However, there are plenty of instances where specs call for the EGC wire in the EMT. Also, some folks like the gold-plated redundancy of the extra wire.

So this thread could concern those installations.

And, IMSO, the connection in the box is not needed. I have seen plenty of folks who say it is, so I figured we needed to argue this a bit.
 
crossman said:
Anytime the code says "equipment grounding conductor" then we must look at 250.118 and you will indeed see that EMT is an equipment grounding conductor. So, the EMT raceway in my scenario is directly mentioned in 250.148 wherever it says equipment grounding conductor.
Click to expand...

I can't help you anymore. Good luck with that logic. Best wishes.

Frizbeedog out!

:cool:
 
Pierre C Belarge said:
First let me say that in your example, I would be one to say it is a violation as per 250.148 and .148(C).

Your choices 1), 2) are for the method of connecting the Grd conductors to the box.
Click to expand...
Agreed. TO the box. It says nothing about INSIDE the box.

Pierre C Belarge said:
Lets remember that grounding screws are not a listed product, so they are not part of #2. That is why number 2 exists
Click to expand...
Well, first, it is not up to the electrician to "guess-assume-play psychology of the CMP" when we read the code. The code is what it says. #2 says that "equipment listed for grounding" can complete the connection between the box and the one or more EGCs present... and it does not say the connection has to be inside the box. EMT and fittings is equipment and can be used for the purpose of connecting EGC wires to boxes, according to 250.148(C).

The EMT does not connect the equipement ground conductors within the box to the box.[/quote]

Where does it say the connection has to be inside the box?

Now, Pierre, with you being an inspector, I suppose it is up to you to interpret what the CMPs intended. But morally, there is a huge responsibility to get it right. A careful and open-minded and unassuming reading of the aforementioned sections will disclose that an internal connection is not needed in my given scenario.
 
RE: Anytime the code says "equipment grounding conductor" then we must look at 250.118 and you will indeed see that EMT is an equipment grounding conductor

frizbeedog said:
I can't help you anymore. Good luck with that logic. Best wishes.
Click to expand...

Before you bail out, you seriously need to look at 250.118. My logic is correct concerning the term Equipment Grounding Conductor.

Also look at ART 100 Definition of the term. There is a FPN leading you to 250.118 for types of EGCs... and EMT is listed.

If you don't believe me, ask some of the highly respected members of this forum. And if you don't see that logic, I guess I can't help YOU anymore.:-?
 
crossman said:
Where does it say the connection has to be inside the box?
Click to expand...


Look up the definition of within, as in connected within the box in 250.148

....and pass the koolaide, 'cause I just can't turn away from circular logic. :wink: :smile:
 
crossman said:
Before you bail out
Click to expand...

OK fine....but you're posting so fast I picture sweat dripping on the keyboard and I'm afraid I won't be able to keep up.....and my pillow is calling.

My glass is empty. I need more koolaide. :grin:

M. D. where are you?
 
Posting so fast? Are you kidding me? Since this thread was started, I been out on the back forty, picked a half-bushel of corn, and been shuckin'. I'm still shuckin'.:)
 
crossman said:
However, there are plenty of instances where specs call for the EGC wire in the EMT. Also, some folks like the gold-plated redundancy of the extra wire.

So this thread could concern those installations.
Click to expand...

Redundantly bond the wire to the box for a gold plated installation. :D

Author's note: My koolaide may be spiked.
 
frizbeedog said:
Redundantly bond the wire to the box for a gold plated installation.
Click to expand...

I'm not saying that you shouldn't bond it if ya want. I have noticed many people assuming you have to, but you don't.

Again, if you read the sections with an open mind, and with an eye for the English language, (and you read exactly what is written, and you don't make assumptions of what was inteneded,) making note of the choices and the "ors", then you just don't have to connect the EGC wire within the box.

Thank you for the interesting dialogue so far!:smile:
 
crossman said:
I'm not saying that you shouldn't bond it if ya want. I have noticed many people assuming you have to, but you don't.

Again, if you read the sections with an open mind, and with an eye for the English language, (and you read exactly what is written, and you don't make assumptions of what was inteneded,) making note of the choices and the "ors", then you just don't have to connect the EGC wire within the box.

Thank you for the interesting dialogue so far!:smile:
Click to expand...

No. Thank you sir. Makes me think a bit more. Those damn ors does it. Can't argure with an or.

.....but I'm not convinced just yet.
 
frizbeedog said:
.....but I'm not convinced just yet.
Click to expand...

:smile: Well, with alot of these code rules, I don't think any of us are totally convinced!

Let me throw in one more scenario to keep you thinking...

Metal panel enclosure, EMT to a 1900 box, then EMT to the load. No green or bare wire in the EMT, just the circuit conductors, and the EMT is used as the EGC as per 250.118, and the EMT and fittings are listed for grounding.

1) The EMT and the couplings and connectors are satisfying 250.148, right? The EMT is the EGC and it is attached to the box. This satisfies the main portion of 148 because the EMT is attached TO the box (within the box OR to the box).

2) This satisfies 148(C) by the second "or" provision, namely "equipment listed for grounding" and the EMT and fittings in my scenario certainly meet that.

So, for this application, EMT satisfies 250.148 and 148(C).

Now add an EGC wire into the EMT. 250.148 requires this new EGC wire to be connected to the box. If the EGC wire is connected to the equipment ground bus in the panel, then that very act makes the EGC wire connected to the box via the EMT/fittings which meet the second provision of 250.148(C).

No need to terminate the EGC wire inside the box.

That's the way I read it!:smile:
 
crossman said:
I'm not saying that you shouldn't bond it if ya want. I have noticed many people assuming you have to, but you don't.

Again, if you read the sections with an open mind, and with an eye for the English language, (and you read exactly what is written, and you don't make assumptions of what was inteneded,) making note of the choices and the "ors", then you just don't have to connect the EGC wire within the box.

Thank you for the interesting dialogue so far!:smile:
Click to expand...
Just so we are clear I am on the emt is grounded bandwagon. However in reality how long and how much money would it take to put in a ground tail then slam a self grounding receptacle in with a screwgun. What are we talking 20 bucks here.
___And what is the point of running the ground wire if you are not going to attatch it to anything??
Use self grounding receptacles and dont run the ground wire and call it a day if you are concerned with production.
 
Quog, the point of the thread isn't production, or reasons why it should be done or why not.

I have seen several folks who indicated they believed it was mandatory, in my original scenario, that the EGC wire be connected to the box, inside the box, with a jumper wire. I just wanted some discussion to see whether it really was mandatory, or if people had just read it and wrong, possibly put meaning in it that wasn't there.

As for your question of where it would be done, what if we just ran the EGC wire from the panel and wanted it terminated at an air compressor. I don't have to put a bonding jumper at the boxes in between if the EMT and fittings are listed for grounding.
 
Status
Not open for further replies.
Top