#4 copper wire
- Thread starter jrmac
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Re: #4 copper wire
Bennie, I've got to ask, where would we feed a downstream panel from another panel at the same capacity, and if we were to do so, why wouldn't we just size one feeder to accomodate both panels the way I explained it?
Roger
Bennie, I've got to ask, where would we feed a downstream panel from another panel at the same capacity, and if we were to do so, why wouldn't we just size one feeder to accomodate both panels the way I explained it?
Roger
jxofaltrds
Inspector Mike®
- Location
- Mike P. Columbus Ohio
- Occupation
- ESI, PI, RBO
Re: #4 copper wire
"The key phrase is "The feeder conductors TO a dwelling unit" Implying that there is only one feeder to this dwelling unit."
If this is true please explain the reference to feeder(s) later in this section. This is what I am having a problem with not the first half.
Mike P.
"The key phrase is "The feeder conductors TO a dwelling unit" Implying that there is only one feeder to this dwelling unit."
If this is true please explain the reference to feeder(s) later in this section. This is what I am having a problem with not the first half.
Mike P.
Re: #4 copper wire
Roger: I'm not clear on what you ask.
Service entrance conductors and feeder conductors are determined according to the load.
A second panel supplied by the first panel will not have a higher calculated load than the service panel. Why have No #4 for the service and #3 for the second panel?
Roger: I'm not clear on what you ask.
Service entrance conductors and feeder conductors are determined according to the load.
A second panel supplied by the first panel will not have a higher calculated load than the service panel. Why have No #4 for the service and #3 for the second panel?
- Location
- Massachusetts
Re: #4 copper wire
Part of 310.15(B)(6)
The one place that could be odd would be 100 amp service disconnect outside use 4 awg from the outside service disconnect to the first panel.
Now if we add a 100 amp panel down stream from that first panel we would have to run 3 AWG.
But
1) When do you in a dwelling unit add a second panel of the same capacity as the first.
2)You could put two service disconnects outside and run 4 awg from each to panels inside.
Part of 310.15(B)(6)
So if we are talking about the service conductors they will never be required to be larger that the feeder.
The one place that could be odd would be 100 amp service disconnect outside use 4 awg from the outside service disconnect to the first panel.
Now if we add a 100 amp panel down stream from that first panel we would have to run 3 AWG.
But
1) When do you in a dwelling unit add a second panel of the same capacity as the first.
2)You could put two service disconnects outside and run 4 awg from each to panels inside.
Re: #4 copper wire
Bennie, no argument that this is a feeder, but it is not a "Main Power Feeder" as defined in 310.15(B)(6). This is the sole reason we can not apply this article section to this (for lack of an NEC term) "Secondary Feeder".
If the section was to allow derating of all feeders it would not have had to waste the ink on text in 310.15(B)(6), the table could have stood alone.
Roger
Bennie, no argument that this is a feeder, but it is not a "Main Power Feeder" as defined in 310.15(B)(6). This is the sole reason we can not apply this article section to this (for lack of an NEC term) "Secondary Feeder".
If the section was to allow derating of all feeders it would not have had to waste the ink on text in 310.15(B)(6), the table could have stood alone.
Roger
jxofaltrds
Inspector Mike®
- Location
- Mike P. Columbus Ohio
- Occupation
- ESI, PI, RBO
Re: #4 copper wire
"Many are going to say the Table 250.15 does not apply."
I think it does. I want to know why I am wrong.
Again the "between" is my problem. Please explain to me why a feeder "from" the disconnect does not use the table.
Mike P.
"Many are going to say the Table 250.15 does not apply."
I think it does. I want to know why I am wrong.
Again the "between" is my problem. Please explain to me why a feeder "from" the disconnect does not use the table.
Mike P.
- Location
- Illinois
- Occupation
- retired electrician
Re: #4 copper wire
In my opinion the table in question can be used for all lighting and appliance branch circuit panels in the dwelling. Look at the definition of "main power feeder" in this section. All feeders to panels meet the requirements of the definition. While the words "main power feeder" strongly implies that this feeder feeds all of the loads in the dwelling unit, there is nothing in the definition that supports this. The definition only has two conditions, 1) that the feeder supply a lighting and appliance branch circuit panel and 2) that the feeder originates on the load side of the service disconnect.
Don
In my opinion the table in question can be used for all lighting and appliance branch circuit panels in the dwelling. Look at the definition of "main power feeder" in this section. All feeders to panels meet the requirements of the definition. While the words "main power feeder" strongly implies that this feeder feeds all of the loads in the dwelling unit, there is nothing in the definition that supports this. The definition only has two conditions, 1) that the feeder supply a lighting and appliance branch circuit panel and 2) that the feeder originates on the load side of the service disconnect.
Don
- Location
- Massachusetts
Re: #4 copper wire
OK I give,
I am sorry Bennie, Don's post made me look at it in a different light.
Looking at the way it's worded the feeder to a "sub panel" is still in between the service disconnect and the panel.
Bob
OK I give,
I am sorry Bennie, Don's post made me look at it in a different light. Looking at the way it's worded the feeder to a "sub panel" is still in between the service disconnect and the panel.
Bob
jxofaltrds
Inspector Mike®
- Location
- Mike P. Columbus Ohio
- Occupation
- ESI, PI, RBO
Re: #4 copper wire
I need affirmation here. I was starting to think that I could not read.
Thank you.
Mike P.
I need affirmation here. I was starting to think that I could not read.
Thank you.
Mike P.
A
a.wayne3@verizon.net
Guest
Re: #4 copper wire
Roger at first I looked at this post and said huh...But you are right as soon as you terminate in your panel any panels after that can`t go by that table anymore.See we all learn something each and every day.That`s why I keep coming back here thanks guys
Allen
Roger at first I looked at this post and said huh...But you are right as soon as you terminate in your panel any panels after that can`t go by that table anymore.See we all learn something each and every day.That`s why I keep coming back here thanks guys
Allen
Re: #4 copper wire
I don't want to create another controversy at this time, but will later on when I describe my reason for concluding all residential panels are service panels, and should be treated as such.
A commercial panel is different due to the feeder usually being installed in a metal conduit. This makes it necessary to take means for preventing parallel load current from flowing on the conduit.
I don't want to create another controversy at this time, but will later on when I describe my reason for concluding all residential panels are service panels, and should be treated as such.
A commercial panel is different due to the feeder usually being installed in a metal conduit. This makes it necessary to take means for preventing parallel load current from flowing on the conduit.
jxofaltrds
Inspector Mike®
- Location
- Mike P. Columbus Ohio
- Occupation
- ESI, PI, RBO
Re: #4 copper wire
"But you are right as soon as you terminate in your panel"
Is a disconnect a panel?
Mike P.
"But you are right as soon as you terminate in your panel"
Is a disconnect a panel?
Mike P.
jxofaltrds
Inspector Mike®
- Location
- Mike P. Columbus Ohio
- Occupation
- ESI, PI, RBO
Re: #4 copper wire
Bennie
"I don't want to create another controversy at this time"
I want you to. You and others have made me think like (as) I never have before.
Mike P.
Bennie
"I don't want to create another controversy at this time"
I want you to. You and others have made me think like (as) I never have before.
Mike P.
Re: #4 copper wire
Don, you stated in your post that it was your opinion that 310.15(B)(6) could be used for all the feeders to panels in dwelling units, so what is your stance?
Would you tell John Mac that the #4 can be protected at 100 amps for this downstream panel, or would you tell him he can not protect it at more than 70 amps for 60 deg C, or 90 amps for 75 deg C?
Roger
Don, you stated in your post that it was your opinion that 310.15(B)(6) could be used for all the feeders to panels in dwelling units, so what is your stance?
Would you tell John Mac that the #4 can be protected at 100 amps for this downstream panel, or would you tell him he can not protect it at more than 70 amps for 60 deg C, or 90 amps for 75 deg C?
Roger
speedypetey
Senior Member
- Location
- Hudson Valley, NY
Re: #4 copper wire
I have always considerd any conductors feeding a panel "feeders", as opposed to branch circuit conductors.
Art. 100-
" Feeder. All circuit conductors between the service equipment, the source of a separately derived system, or other power supply source and the final branch-circuit overcurrent device."
Wouldn't conductors between the service equipment (main panel) and the final overcurrent device (sub-panel, sorry Bennie) be feeders by this definition?
This is why I asked my original question.
I have always considerd any conductors feeding a panel "feeders", as opposed to branch circuit conductors.
Art. 100-
" Feeder. All circuit conductors between the service equipment, the source of a separately derived system, or other power supply source and the final branch-circuit overcurrent device."
Wouldn't conductors between the service equipment (main panel) and the final overcurrent device (sub-panel, sorry Bennie) be feeders by this definition?
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