Additional Panel
- Thread starter bennie
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highkvoltage
Senior Member
Re: Additional Panel
Bennie. Either you would have to add a fouth wire for an equipment ground marked green or if the neutral is long enough change the markings to green and land it on the equipment ground bus in both panels. I would add the fourth wire for future just in case somewhere down the road you need a grounded conductor at the panel you installed.
Bennie. Either you would have to add a fouth wire for an equipment ground marked green or if the neutral is long enough change the markings to green and land it on the equipment ground bus in both panels. I would add the fourth wire for future just in case somewhere down the road you need a grounded conductor at the panel you installed.
pierre
Senior Member
- Location
- Westchester County, New York
Re: Additional Panel
Bennie
This is a good question!!!! I would like to know more about your proposed feeder to this 240v load only 'additional' panel.
How is the feeder installed, PVC, metallic enclosure, NM?
The supply side of the 'neutral' conductor is connected to where? (1st point of disconnect or another 'additional' panel?
Pierre
Bennie
This is a good question!!!! I would like to know more about your proposed feeder to this 240v load only 'additional' panel.
How is the feeder installed, PVC, metallic enclosure, NM?
The supply side of the 'neutral' conductor is connected to where? (1st point of disconnect or another 'additional' panel?
Pierre
highkvoltage
Senior Member
Re: Additional Panel
The installation you used has nothing to do with the question. Some would assume that if you used metal conduit that this could be your equipment ground path, I feel this is a poor way to go. It really doesn't matter where your circuit starts you still have to carry your equipment ground from the grounding bus. (I'm not one who likes to mix up my grounded wires and grounding wire in a mixed fashion. I like to keep them separated.) Whether you decide to use the grounded conductor for the equipment ground is really only determined on the conditions I stated before:
1. Is the neutral long enough to land on the grounding bus?
2. Do you foresee any reason in the future you may need the neutral in the panel you are installing? It is far easier now to install the 4th or 5th wire (single phase or 3 phase) now than in the future. If this is a bid job I normally explain this to my customer and they see that this is very practical way to go.
3.If the run isn't that long and if the conduit is large enough just pull in a equipment grounding conductor.
I understand that this could be a 3 phase panel strickly for power to run equipment but I always try to look ahead. If this was a 480 volt circuit I would look at it a little differently and concider some other options but this is an easy call.
The installation you used has nothing to do with the question. Some would assume that if you used metal conduit that this could be your equipment ground path, I feel this is a poor way to go. It really doesn't matter where your circuit starts you still have to carry your equipment ground from the grounding bus. (I'm not one who likes to mix up my grounded wires and grounding wire in a mixed fashion. I like to keep them separated.) Whether you decide to use the grounded conductor for the equipment ground is really only determined on the conditions I stated before:
1. Is the neutral long enough to land on the grounding bus?
2. Do you foresee any reason in the future you may need the neutral in the panel you are installing? It is far easier now to install the 4th or 5th wire (single phase or 3 phase) now than in the future. If this is a bid job I normally explain this to my customer and they see that this is very practical way to go.
3.If the run isn't that long and if the conduit is large enough just pull in a equipment grounding conductor.
I understand that this could be a 3 phase panel strickly for power to run equipment but I always try to look ahead. If this was a 480 volt circuit I would look at it a little differently and concider some other options but this is an easy call.
pierre
Senior Member
- Location
- Westchester County, New York
Re: Additional Panel
Bennie
I am hypothesizing here... Not using the NEC as reference, but trying to rationalize sort of....
For #3
I could see using the grounded conductor to carry fault current back as the PVC would not pose a problem of carrying current - in essence the grounded conductor in this example is an equipment grounding conductor.
For # 1&2, I see, in my limited way, that the grounded conductor and the equipment grounding conductor need to be separated so as the equipment ground conductor only carries fault current.
The problem is not only the shock hazard, but the chance of over a period of time a fire hazard exists as well.
Pierre
Bennie
I am hypothesizing here... Not using the NEC as reference, but trying to rationalize sort of....
For #3
I could see using the grounded conductor to carry fault current back as the PVC would not pose a problem of carrying current - in essence the grounded conductor in this example is an equipment grounding conductor.
For # 1&2, I see, in my limited way, that the grounded conductor and the equipment grounding conductor need to be separated so as the equipment ground conductor only carries fault current.
The problem is not only the shock hazard, but the chance of over a period of time a fire hazard exists as well.
Pierre
scott thompson
Senior Member
- Location
- Anaheim, California
Re: Additional Panel
Just a few hints:
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It's a very simple answer! Just look at the entire picture first!
Scott35
Just a few hints:
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- <font size="2" face="Verdana, Helvetica, sans-serif">Bennie's last post covers it all!,</font>
- <font size="2" face="Verdana, Helvetica, sans-serif">It will be the same as any other type of Bonding Conductor,</font>
- <font size="2" face="Verdana, Helvetica, sans-serif">Raceway could be Metallic or Non-Metallic with similar results,</font>
- <font size="2" face="Verdana, Helvetica, sans-serif">Could be a Multiconductor Cable with same results,</font>
- <font size="2" face="Verdana, Helvetica, sans-serif">The Color of the Insulation does not result in a Current flowing, nor does the Color Impede a flow of Currents!,</font>
- <font size="2" face="Verdana, Helvetica, sans-serif">Biggest hint: Where does this "Neutral Wire" originate from?</font>
It's a very simple answer! Just look at the entire picture first!
Scott35
Re: Additional Panel
Pierre: I fail to see a fire danger or a shock hazard with 3 wires to a panel. Two active line conductors, one equipment ground conductor from the service neutral bus. This is the same as using the neutral to ground the panel.
Like my other scenario about a water heater; An equipment ground conductor from the added panel to the heater would also connect to the cold water pipe which is a ground electrode.
Can you convince me this is not earth grounding the neutral after the main switch?
Load current can flow in a green wire and fault current can flow in a white one.
Pierre: I fail to see a fire danger or a shock hazard with 3 wires to a panel. Two active line conductors, one equipment ground conductor from the service neutral bus. This is the same as using the neutral to ground the panel.
Like my other scenario about a water heater; An equipment ground conductor from the added panel to the heater would also connect to the cold water pipe which is a ground electrode.
Can you convince me this is not earth grounding the neutral after the main switch?
Load current can flow in a green wire and fault current can flow in a white one.
Re: Additional Panel
The purpose of color coding isn't to keep the electricity in check, but rather to give the next electrician a good idea of what to expect. if you want to re-identify a conductor as a grounding conductor, then follow the rules for identifying conductors. Would you sanction running three #12 green conductors to a receptacle outlet? The next guy can always check for voltage with the proper equipment, can't he? Where do we draw the line?
The purpose of color coding isn't to keep the electricity in check, but rather to give the next electrician a good idea of what to expect. if you want to re-identify a conductor as a grounding conductor, then follow the rules for identifying conductors. Would you sanction running three #12 green conductors to a receptacle outlet? The next guy can always check for voltage with the proper equipment, can't he? Where do we draw the line?
karl riley
Senior Member
Re: Additional Panel
Bennie, I am going to play along with this, since I do think you like to play.
You mentioned an "added panel". Where in the NEC is "added panel" defined? Do you call the "added panel" a service panel, a sub-service panel, part of a multiple-service-panel service?
Karl
Bennie, I am going to play along with this, since I do think you like to play.
You mentioned an "added panel". Where in the NEC is "added panel" defined? Do you call the "added panel" a service panel, a sub-service panel, part of a multiple-service-panel service?
Karl
karl riley
Senior Member
Re: Additional Panel
Bennie, I am going to play along with this, since I do think you like to play.
You mentioned an "added panel". Where in the NEC is "added panel" defined? Do you call the "added panel" a service panel, a sub-service panel, part of a multiple-service-panel service?
Karl
Bennie, I am going to play along with this, since I do think you like to play.
You mentioned an "added panel". Where in the NEC is "added panel" defined? Do you call the "added panel" a service panel, a sub-service panel, part of a multiple-service-panel service?
Karl
- Location
- Massachusetts
Re: Additional Panel
That strains your credibility.
Re: Additional Panel
OK, six loadcenters on a wall, all supplied by one set of service conductors.
Would the panels be service panels?
Now spread the panels throughout the building. The only thing that changes is the location. Are they still service panels?
Adding switches and breakers on the feeder does not change anything.
Unless proven otherwise my credibility is unquestionable.
[ March 03, 2004, 05:27 PM: Message edited by: bennie ]
OK, six loadcenters on a wall, all supplied by one set of service conductors.
Would the panels be service panels?
Now spread the panels throughout the building. The only thing that changes is the location. Are they still service panels?
Adding switches and breakers on the feeder does not change anything.
Unless proven otherwise my credibility is unquestionable.
[ March 03, 2004, 05:27 PM: Message edited by: bennie ]
- Location
- Massachusetts
Re: Additional Panel
Bennie the majority of us are subject to inspections under the requirements of the NEC, we do not do our work on a piece of paper where we can control all outside influences.
As Don said, call the panels whatever you want but the important point as far as the NEC is concerned is the location of the Service Disconnect
Line side of the Service Disconnect is treated one way, the load side Service Disconnect is treated another way.
Don't you ever get tired of this conversation? :roll:
[ March 03, 2004, 05:47 PM: Message edited by: iwire ]
Bennie the majority of us are subject to inspections under the requirements of the NEC, we do not do our work on a piece of paper where we can control all outside influences.
Under the rules of the NEC the addition of switch changes a service conductor to a feeder.
Yes they would all be service panels.
No, they are not now service panels, as there would be a required OCPD and switch back at the service entrance.
As Don said, call the panels whatever you want but the important point as far as the NEC is concerned is the location of the Service Disconnect
Line side of the Service Disconnect is treated one way, the load side Service Disconnect is treated another way.
Don't you ever get tired of this conversation? :roll:
[ March 03, 2004, 05:47 PM: Message edited by: iwire ]
highkvoltage
Senior Member
Re: Additional Panel
I can not imagine an inspector allowing a subpanel at a house to not have 4 conductors brought to it. Your conductors would have to rated for 125%. To feed a 100 amp subpanel and for you to have the ability to have 100 amps at the subpanel your branch circuit would have to be #1 THHN (Table 310.16). Your lugs at the panel would only be rated for 75 deg C. The conductor size would not change whether you use a neutral or not. Your grounding conductor then would be sized at #6 THHN(Table 250.122). Your CB at your main panel would 100 amp. If you was going alum. then your conductor sizes would be 2/0 but you could use USE and not have to run any conduit. Since your can get 4 conductor for almost the same price as 3 conductor again it's a no brainer. :roll:
I can not imagine an inspector allowing a subpanel at a house to not have 4 conductors brought to it. Your conductors would have to rated for 125%. To feed a 100 amp subpanel and for you to have the ability to have 100 amps at the subpanel your branch circuit would have to be #1 THHN (Table 310.16). Your lugs at the panel would only be rated for 75 deg C. The conductor size would not change whether you use a neutral or not. Your grounding conductor then would be sized at #6 THHN(Table 250.122). Your CB at your main panel would 100 amp. If you was going alum. then your conductor sizes would be 2/0 but you could use USE and not have to run any conduit. Since your can get 4 conductor for almost the same price as 3 conductor again it's a no brainer. :roll:
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