Sometimes I am tempted to take a large gound wire or GEC and connect it to a lug I would be bolting to the panel instead of directly to the N/G bar because the wire is too large to fit or N/G bar to small. If I were to do that the case of the the panel would be the EGC or GEC respectively. Woul either scenario pose a problem or code violation.
grounding specfics.
- Thread starter jes25
- Start date
- Status
jimwalker
Senior Member
- Location
- TAMPA FLORIDA
Re: grounding specfics.
what do you call LARGE and what amperage panels ?
what do you call LARGE and what amperage panels ?
- Location
- Bremerton, Washington
- Occupation
- Master Electrician
Re: grounding specfics.
Some mfgs make adapters that fit into a ground bus with 2 forks that are connected to a set screw lug for a large size conductor.
Some mfgs make adapters that fit into a ground bus with 2 forks that are connected to a set screw lug for a large size conductor.
Re: grounding specfics.
Joe, along with Derecks post, if I were the inspector I'd also point out 110.5, I would ask where the steel of this enclosure is accepted as a conductor.
Then I'd also bring up the fact that you are required to bond the enclosure and that the enclosure is not a bond to the EGC or GEC.
Roger
Joe, along with Derecks post, if I were the inspector I'd also point out 110.5, I would ask where the steel of this enclosure is accepted as a conductor.
Then I'd also bring up the fact that you are required to bond the enclosure and that the enclosure is not a bond to the EGC or GEC.
Roger
Re: grounding specfics.
Roger the steel is an acceptable EGC when you use emt without pulling a seperate egc.
AT any rate I wont be doing this, Think I might keep some of those lug adapters on my truck that tom was talking about.
Thanks
Roger the steel is an acceptable EGC when you use emt without pulling a seperate egc.
AT any rate I wont be doing this, Think I might keep some of those lug adapters on my truck that tom was talking about.
Thanks
- Location
- Wisconsin
- Occupation
- PE (Retired) - Power Systems
Re: grounding specfics.
Roger,
How does an panelboard enclosure not meet 250.118(14)?
110.5 is not applicable because an EGC is not a normal current carrying conducotr.
If one run of EMT is connected at the bottom left of the enclosure and a different run is allow connected at the center top, is'nt the enclosure acting as part of the equipment ground circuit/conductor?
Roger,
How does an panelboard enclosure not meet 250.118(14)?
110.5 is not applicable because an EGC is not a normal current carrying conducotr.
If one run of EMT is connected at the bottom left of the enclosure and a different run is allow connected at the center top, is'nt the enclosure acting as part of the equipment ground circuit/conductor?
Re: grounding specfics.
Jim, where is the reason or definition that an EGC is not a normal current carrying conductor in writing?
Can you show me where a Panel enclosure is called a "continuous metal raceway or auxiliary gutter listed for grounding" as required by 250.118(14)?
If so, then it is allowed.
I personally don't see a problem, but as I said in my first post, I would ask for the same as I'm asking you to provide in this post.
Roger
Jim, where is the reason or definition that an EGC is not a normal current carrying conductor in writing?
Can you show me where a Panel enclosure is called a "continuous metal raceway or auxiliary gutter listed for grounding" as required by 250.118(14)?
If so, then it is allowed.
I personally don't see a problem, but as I said in my first post, I would ask for the same as I'm asking you to provide in this post.
Roger
- Location
- Wisconsin
- Occupation
- PE (Retired) - Power Systems
Re: grounding specfics.
Roger, according to 250.2 a Ground-Fault Current Path is a normally non-current-carrying conductor which can include equipment.
Since when can a panelboard enclosure not be considered a Raceway per article 100 part I? 408.2 says a panelboard enclosure must meet the requirements of both article 250 and 314.
Roger, according to 250.2 a Ground-Fault Current Path is a normally non-current-carrying conductor which can include equipment.
Since when can a panelboard enclosure not be considered a Raceway per article 100 part I? 408.2 says a panelboard enclosure must meet the requirements of both article 250 and 314.
hurk27
Senior Member
- Location
- Portage, Indiana NEC: 2008
Re: grounding specfics.
First I don't think the panel would have any problem with a single circuit fault ran in EMT.
But consider a service fault and the fact that service conductors are not protected by any OCPD's This could cause a failure of this connection. And if this connection did blow open it could heat up all the grounding in the building with it.
First I don't think the panel would have any problem with a single circuit fault ran in EMT.
But consider a service fault and the fact that service conductors are not protected by any OCPD's This could cause a failure of this connection. And if this connection did blow open it could heat up all the grounding in the building with it.
Re: grounding specfics.
When I use to do commercial work, We used to knock out a hole in a panelboard run emt out of it to a plug. Than at the 4" sq. box we take a gnd pigtail and hook it to the plug and the emt is the EGC, WE have all seen this 1000's of times . Now the panelboards' EGC is hooked to ground bar in the panel and the panel enclosure bonded. That panel is acting as the egc from the point the pipe touches to the point the bonding jumper touches the panel. What am I missing? The panel enclosure acts as a grounding conductor for every circuit you dont pull a ground for.
When I use to do commercial work, We used to knock out a hole in a panelboard run emt out of it to a plug. Than at the 4" sq. box we take a gnd pigtail and hook it to the plug and the emt is the EGC, WE have all seen this 1000's of times . Now the panelboards' EGC is hooked to ground bar in the panel and the panel enclosure bonded. That panel is acting as the egc from the point the pipe touches to the point the bonding jumper touches the panel. What am I missing? The panel enclosure acts as a grounding conductor for every circuit you dont pull a ground for.
Re: grounding specfics.
I must say I don't see a problem at all with the original question. It would be no different than having a supplemental bar bolted to the can and landing some of the grounds or neutrals on it. It would still have to go thru the can to the neutral. Its done all the time as long as no sheet metal screw is used and the lug is secured by a bolt. It is ALL bonded together solidly. BTW that is as long as we are talking about service equipment...
I must say I don't see a problem at all with the original question. It would be no different than having a supplemental bar bolted to the can and landing some of the grounds or neutrals on it. It would still have to go thru the can to the neutral. Its done all the time as long as no sheet metal screw is used and the lug is secured by a bolt. It is ALL bonded together solidly. BTW that is as long as we are talking about service equipment...
- Location
- Massachusetts
Re: grounding specfics.
You can bolt a supplemental bar to the enclosure and land grounding conductors on it, you can not land grounded conductors on this supplemental bar.
If you land grounded conductors on this bar you will be using the steel of the enclosure as a conductor that normally carries current, that is a violation of 110.5
But now that I have said that I also agree with Roger, there is nothing in the NEC that tells the steel of a panel board cabinet may be used as a EGC.
We all have done it and I see nothing wrong with it, but it should be listed in 250.118.
Look at the beginning of 250.118
Article 100
[ August 08, 2004, 09:32 AM: Message edited by: iwire ]
I disagree with part of that.
You can bolt a supplemental bar to the enclosure and land grounding conductors on it, you can not land grounded conductors on this supplemental bar.
If you land grounded conductors on this bar you will be using the steel of the enclosure as a conductor that normally carries current, that is a violation of 110.5
You will not find any section in the code that modifies 110.5 requirements for grounded conductors. IMO using a panel enclosure as a conductor to normally carry current is not a good idea.
But now that I have said that I also agree with Roger, there is nothing in the NEC that tells the steel of a panel board cabinet may be used as a EGC.
We all have done it and I see nothing wrong with it, but it should be listed in 250.118.
Look at the beginning of 250.118
I agree 250.118(14) comes close...untill we look at the NEC definition of Panelbaord.
Article 100
[ August 08, 2004, 09:32 AM: Message edited by: iwire ]
Re: grounding specfics.
I think there's also a question of equipment approval here under 110-2 and 110-3. Under 250-8 Grounding conductors must be connected by "listed means". The lug and can may be listed, but drilling a hole and bolting it to the can may be not be specifically allowed by the panelboard manufacturer, which violates 110-3(b). IMO, unless the can has holes designed for installing a ground lug, or the manufacturer indicates in the specs that drilling such holes is approved, it's a violation. The supplemental ground bars I use (in contrast) are listed for the panelboard, which has identified threaded holes for the purpose.
Anecdote on the point: I had to replace a J-box not too long ago, because a previous installer had mangled the ground screw hole. It was in a finished wall, so I drilled and tapped a new hole. It was deemed an "Unapproved field modification"! And I couldn't just substitute an approved grounding clip, because I'd drilled the box.
I think there's also a question of equipment approval here under 110-2 and 110-3. Under 250-8 Grounding conductors must be connected by "listed means". The lug and can may be listed, but drilling a hole and bolting it to the can may be not be specifically allowed by the panelboard manufacturer, which violates 110-3(b). IMO, unless the can has holes designed for installing a ground lug, or the manufacturer indicates in the specs that drilling such holes is approved, it's a violation. The supplemental ground bars I use (in contrast) are listed for the panelboard, which has identified threaded holes for the purpose.
Anecdote on the point: I had to replace a J-box not too long ago, because a previous installer had mangled the ground screw hole. It was in a finished wall, so I drilled and tapped a new hole. It was deemed an "Unapproved field modification"! And I couldn't just substitute an approved grounding clip, because I'd drilled the box.
hurk27
Senior Member
- Location
- Portage, Indiana NEC: 2008
Re: grounding specfics.
Here is what I see. Most panels that are listed for use as service equipment allow the grounding conductors to be connected to the same bar that the service grounded (neutral) conductor is connected to. They even go through the trouble to manufacture a jumper bar that connects between both halves of these bars and some even allow the removal of it only when the panel is not used as service equipment. These panels provide plenty of terminals to land both grounded and grounding conductors on these bars. But there are a few panels that only have enough terminals for the grounded conductors and require us to purchase a grounding bar. This grounding bar will either come with a jumper or have instructions that require a jumper when it is used in a panel that is installed as service equipment. 250.28 seems to require this but it does allow screws to be used. But when you read the last statement in (D) of this article it sounds like it has to be listed, unless you are a engineer that can figure out what size and kind of material it should be made of? It just seems like the NEC wants a very good connection between these two bars. At least that's my thought's Maybe we could get a CMP to commit on this?
Here is what I see. Most panels that are listed for use as service equipment allow the grounding conductors to be connected to the same bar that the service grounded (neutral) conductor is connected to. They even go through the trouble to manufacture a jumper bar that connects between both halves of these bars and some even allow the removal of it only when the panel is not used as service equipment. These panels provide plenty of terminals to land both grounded and grounding conductors on these bars. But there are a few panels that only have enough terminals for the grounded conductors and require us to purchase a grounding bar. This grounding bar will either come with a jumper or have instructions that require a jumper when it is used in a panel that is installed as service equipment. 250.28 seems to require this but it does allow screws to be used. But when you read the last statement in (D) of this article it sounds like it has to be listed, unless you are a engineer that can figure out what size and kind of material it should be made of? It just seems like the NEC wants a very good connection between these two bars. At least that's my thought's Maybe we could get a CMP to commit on this?
- Location
- Wisconsin
- Occupation
- PE (Retired) - Power Systems
Re: grounding specfics.
Wayne,
The original question had to asked if it was okay to use the panel enclosure as an EGC.
I don't think anyone is debating if the panel enclosure can be used as the bonding between the neutral and ground bars.
Wayne,
The original question had to asked if it was okay to use the panel enclosure as an EGC.
I don't think anyone is debating if the panel enclosure can be used as the bonding between the neutral and ground bars.
hurk27
Senior Member
- Location
- Portage, Indiana NEC: 2008
Re: grounding specfics.
Jim I guess I don't understand the original question.
What I was thinking he was asking was if he could install a lug to the can to accept the larger grounding electrode conductors or a larger equipment grounding conductor. Because of the neutral/ grounding bar terminals being too small. And if this is what he was asking then I don't think the intent of the NEC allows it. as for single branch circuits It wouldn't be a problem. IE: in conduit, but I don't think the steel in a panel was meant to carry the large fault currents that could be imposed on it from a lightning strike or a fault in the service entrance conductor if it had to depend upon this connection.
I had a panel that the neutral bar was bonded in this manner and when the service entrance conductor shorted to the panel the first thing to open was this connection. This left all the grounding hot throughout the house and caused a few shocks before it was called in.
Jim I guess I don't understand the original question.
What I was thinking he was asking was if he could install a lug to the can to accept the larger grounding electrode conductors or a larger equipment grounding conductor. Because of the neutral/ grounding bar terminals being too small. And if this is what he was asking then I don't think the intent of the NEC allows it. as for single branch circuits It wouldn't be a problem. IE: in conduit, but I don't think the steel in a panel was meant to carry the large fault currents that could be imposed on it from a lightning strike or a fault in the service entrance conductor if it had to depend upon this connection.
I had a panel that the neutral bar was bonded in this manner and when the service entrance conductor shorted to the panel the first thing to open was this connection. This left all the grounding hot throughout the house and caused a few shocks before it was called in.
- Location
- Wisconsin
- Occupation
- PE (Retired) - Power Systems
Re: grounding specfics.
I just re-read the original post. There were two questions asked, I believe the answers are:
Panel enclosure as EGC - yes, it is treated the same as any other component in the raceway system just like any cabinet or junction box.
Panel enclosure as GEC - no, it is not one of the approved conductors, again the same as any other raceway component.
I just re-read the original post. There were two questions asked, I believe the answers are:
Panel enclosure as EGC - yes, it is treated the same as any other component in the raceway system just like any cabinet or junction box.
Panel enclosure as GEC - no, it is not one of the approved conductors, again the same as any other raceway component.
- Status