- Location
- Massachusetts
Put your tongue back in and tell me why you think so.
Because I read the thread title and the opening post. :thumbsup:
Power panel as means of grounding path.
- Thread starter jimej4
- Start date
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Because I read the thread title and the opening post. :thumbsup:
- Location
- Tennessee NEC:2017
- Occupation
- Semi-Retired Electrician
I read that too. I have talked to/read about people that knew something was in the code about panels and grounding but couldn't remember exactly what. I just thought the OP, in the back of his mind, might be thinking of 200.2(B)
ptonsparky
Tom
- Occupation
- EC - retired
IMO, yes the enclosure can be used as a path for equipment ground. Mostly just because common sense would allow it, but that really has no code support. Your next options are stack all the lugs under one bolt or put in an EG bar. I personally put in XXX ground bars because that is what we stock. Don't care whose 40 year old enclosure it is.
- Location
- Tennessee NEC:2017
- Occupation
- Semi-Retired Electrician
How do you mount the ground bar? It seems some panels are too thin to drill and tap.
ptonsparky
Tom
- Occupation
- EC - retired
A 40 yr old enclosure will not be to thin. I use the self threading screws that come with the bar. Make sure to scrap the paint off.
marti smith
Senior Member
250.80 (2011).
- Location
- Illinois
- Occupation
- retired electrician
That tells us that the metal non-current carrying parts of the service equipment have to be bonded. That does no tell us that the metal parts of the service equipment are EGCs,
Sorry I don't have a 2011 NEC avaible but check out NEC 2002, Art. 250.96
Art 250.96 Bonding Other Enclosures.
(A) General. Metal,cable trays,cable Armor,cable sheat,enclosures,frames,fittings and other metal non-current -carrying parts that are to serve as grounding conductors,with or without the use of supplementary equipment grounding conductors.
Ronald)
Art 250.96 Bonding Other Enclosures.
(A) General. Metal,cable trays,cable Armor,cable sheat,enclosures,frames,fittings and other metal non-current -carrying parts that are to serve as grounding conductors,with or without the use of supplementary equipment grounding conductors.
Ronald
)
- Location
- Illinois
- Occupation
- retired electrician
Sorry I don't have a 2011 NEC avaible but check out NEC 2002, Art. 250.96
Art 250.96 Bonding Other Enclosures.
(A) General. Metal,cable trays,cable Armor,cable sheat,enclosures,frames,fittings and other metal non-current -carrying parts that are to serve as grounding conductors,with or without the use of supplementary equipment grounding conductors.
Ronald
That just about says that the enclosure is an EGC. In the 2011 code they did add the word "equipment" before grounding, but it still doesn't come right out and say we can use the enclosure as an EGC. I know that we do and I know that is the intent of the code, but I still don't see anything that actually comes out and directly says that the enclosure can be used as an EGC.
stew
Senior Member
- Location
- federal way,washington
In my opinion 250.118(13) allows it because it says electrically continous raceways. Those who say that the panel is not a reaceway might want to think about the restriction of running branch circuits and service conductors in the same raceway. I once removed the guts of a panel and did the branch circuit splicing in the old panel. I then put 2 nipples out to the new panel and spliced the service conductors in the old panel and ran those thru on nipple and the branch circuits in the other nipple. Guess what? The panel like magic became a raceway!!! red tag city. Everyone on here in a very sprited post all agreed that the panel was a raceway. now we are saying its not?
- Location
- Illinois
- Occupation
- retired electrician
You left out a key word in your description of what 250.118(13) says.
The panel enclosure is not a listed raceway or listed auxiliary gutter.
stew
Senior Member
- Location
- federal way,washington
hmmmm well all I know is it was considered a reaceway in the scenario I described and of course was electrically continous. Listed hmmm guess i wouldnt know if it was or wasnt.
renosteinke
Senior Member
- Location
- NE Arkansas
"it's accepted practice ...." I just have to love that statement. Indeed, I have to say it makes a tremendous amount of sense. However, like it's sibling "we've always done it," it's all to easy to counter with 'well, you've been doing it wrong all that time.' I will make a blanket statement that 'tradition' is a powerful justification, and that far too many folks have far too much 'book learning.' As they say, the NEC is not an instruction book.
As I see it, an enclosure is but another part of the raceway. Wher we have a non-conductive enclosure, we are required to have a bonding jumper between the metal raceway parts. IMO, this implies that the enclosure itself, if conductive, qualifies as part of the EGC (bonding wire).
Yet, I've also seen panels with multiple lugs screwed to them. While I believe this is legal, don't like it. I'd much rather see a nice ground buss. That, in turn, leads me to my next concern.
Just what is the ampacity of #16 sheet metal? That's always bothered me- so it's been my personal practice to connect various ground busses with a 'real' wire, and not rely soley upon the mountings to make the connections. What size wire? I can see many ways to derive a wire size, but I also suspect that even a #14 copper wire has to be better than a few threads on a steel screw.
After all, the sole reason got that ground path is to clear faults- so we have a reason to make that path as low an impedence as we can. If the mounting screws are not adequate for devices, why should we trust them for bussbars and lugs?
That's my belief - but, please, do not assume I would support a code change on this point. "Good practice" is something apart from "good law."
As I see it, an enclosure is but another part of the raceway. Wher we have a non-conductive enclosure, we are required to have a bonding jumper between the metal raceway parts. IMO, this implies that the enclosure itself, if conductive, qualifies as part of the EGC (bonding wire).
Yet, I've also seen panels with multiple lugs screwed to them. While I believe this is legal, don't like it. I'd much rather see a nice ground buss. That, in turn, leads me to my next concern.
Just what is the ampacity of #16 sheet metal? That's always bothered me- so it's been my personal practice to connect various ground busses with a 'real' wire, and not rely soley upon the mountings to make the connections. What size wire? I can see many ways to derive a wire size, but I also suspect that even a #14 copper wire has to be better than a few threads on a steel screw.
After all, the sole reason got that ground path is to clear faults- so we have a reason to make that path as low an impedence as we can. If the mounting screws are not adequate for devices, why should we trust them for bussbars and lugs?
That's my belief - but, please, do not assume I would support a code change on this point. "Good practice" is something apart from "good law."
kwired
Electron manager
- Location
- NE Nebraska
You could not call the old panel cabinet a raceway, if you did you could not make splices in it. It is still a cabinet - with the panelboard removed. You could have had service/branch circuit conductors in it but would have to have a barrier between sections that need separated.
Since there were service conductors in there it must be bonded to the service grounded conductor - you possibly would not want to install bonding jumper in the new panel. Grounding electrode conductor would have to run to this enclosure if that were the case.
Not trying to hijack the thread.
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stew
Senior Member
- Location
- federal way,washington
k wire i believe you were one of the guys who insisted it was at the time.
stew
Senior Member
- Location
- federal way,washington
oops sorry k wire. looked back and it was Iwire
- Location
- Mission Viejo, CA
- Occupation
- Professional Electrical Engineer
One of the problems with English ambiguity is if you get too precise you either start excluding things that should be acceptable or end up with a ten page list with attending exceptions. To recognize and accept legitimate alternatives is the real purpose of the “responsibility” clause in Section 90.4.
Since it is a non-exclusive list, I submit the Article 100 definition of raceway is sufficiently broad that many enclosures would be included. At which point they would be acceptable under 250.118(13) if they are listed. The question would be,"are they listed for grounding?" The UL “White Book” does recognize some enclosures may need specific field installed grounding kits.
Since it is a non-exclusive list, I submit the Article 100 definition of raceway is sufficiently broad that many enclosures would be included. At which point they would be acceptable under 250.118(13) if they are listed. The question would be,"are they listed for grounding?" The UL “White Book” does recognize some enclosures may need specific field installed grounding kits.
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Electron_Sam78
Senior Member
- Location
- Palm Bay, FL
to the OP: the NEC does not disallow the enclosure frame to be used as a grounding path. However if the neutral is bonded to the grounding conductor and enclosure frame as allowed in certain circustances the frame of the enclosure cannot be used as a current return path. What this means is that as long as the conductors you see attached to the enclosure frame are only equipment grounding conductors it is fine but if they are "neutrals" it is not allowed.
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