#4 copper wire
- Thread starter jrmac
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Re: #4 copper wire
Yes, you can buy #4 "3 conductor with ground" cables in NM, SER, MC etc... but the #4 is not large enough for a 100 amp panel downstream of your Main lighting and appliance branch circuit panel.
You will have to use #3 with a 75 deg C listing for this or protect this new panel at a lower amperage.
Roger
[ January 01, 2004, 10:04 PM: Message edited by: roger ]
Yes, you can buy #4 "3 conductor with ground" cables in NM, SER, MC etc... but the #4 is not large enough for a 100 amp panel downstream of your Main lighting and appliance branch circuit panel.
You will have to use #3 with a 75 deg C listing for this or protect this new panel at a lower amperage.
Roger
[ January 01, 2004, 10:04 PM: Message edited by: roger ]
speedypetey
Senior Member
- Location
- Hudson Valley, NY
Re: #4 copper wire
Roger, why is this the case. Isn't a panel fed by a feeder?
Roger, why is this the case. Isn't a panel fed by a feeder?
curt swartz
Electrical Contractor - San Jose, CA
- Location
- San Jose, CA
- Occupation
- Electrical Contractor
Re: #4 copper wire
Speedypetey
310.15(B)(6) only allows the conductor sizes shown in table 310.15(B)(6) for the main power feeder to a dwelling. The feeder in question is not considered the main power feeder.
Speedypetey
310.15(B)(6) only allows the conductor sizes shown in table 310.15(B)(6) for the main power feeder to a dwelling. The feeder in question is not considered the main power feeder.
- Location
- Massachusetts
Re: #4 copper wire
Just above Table 310.15(B)(6) is section 310.15(B)(6) part of which says:
Just above Table 310.15(B)(6) is section 310.15(B)(6) part of which says:
pierre
Senior Member
- Location
- Westchester County, New York
Re: #4 copper wire
Any panel that is past (downstream) of the first lighting and appliance branch-circuit panel in a dwelling is not permitted to use the table 310.15(B)(6). Also that table does not have NM cable (most widely known as Romex)as one of the permitted types of conductor/cable types.
Example:
A service disconnect (located immediately inside or outside the dwelling) feeds the main panel in a dwelling, that is one example of a main power feeder as per NEC.
Supplying a panel from the main panel in a dwelling, the feeders supplying the second panel are not considered main power feeders and one cannot use table 310.15(B)(6).
Pierre
Any panel that is past (downstream) of the first lighting and appliance branch-circuit panel in a dwelling is not permitted to use the table 310.15(B)(6). Also that table does not have NM cable (most widely known as Romex)as one of the permitted types of conductor/cable types.
Example:
A service disconnect (located immediately inside or outside the dwelling) feeds the main panel in a dwelling, that is one example of a main power feeder as per NEC.
Supplying a panel from the main panel in a dwelling, the feeders supplying the second panel are not considered main power feeders and one cannot use table 310.15(B)(6).
Pierre
Re: #4 copper wire
There is no such thing as a subpanel. Therefore there is no feeder for a sub-panel.
Table 310.15.B.6 Is titled; Conductor types and sizes for Single phase Dwelling Services and Feeders.
No feeder is required to be larger than the service entrance conductors.
All supply conductors to dwelling panels are included in the Table 310.15.B.6.
There is no such thing as a subpanel. Therefore there is no feeder for a sub-panel.
Table 310.15.B.6 Is titled; Conductor types and sizes for Single phase Dwelling Services and Feeders.
No feeder is required to be larger than the service entrance conductors.
All supply conductors to dwelling panels are included in the Table 310.15.B.6.
- Location
- Massachusetts
Re: #4 copper wire
Bennie you should read the section in question before saying the table applies to all dwelling unit feeders.
We do not even have to go down the sub panel route to figure out what the table applies to.
Part of section 310.15(B)(6)
[ January 02, 2004, 09:54 AM: Message edited by: iwire ]
Bennie you should read the section in question before saying the table applies to all dwelling unit feeders.
We do not even have to go down the sub panel route to figure out what the table applies to.
Part of section 310.15(B)(6)
No mention of a sub panel but still clear this table is only for main feeders.
[ January 02, 2004, 09:54 AM: Message edited by: iwire ]
Re: #4 copper wire
Bob: All dwelling panels are lighting and power panels. The supply to each one is the main power feeder.
Read the paragraph below the one about main power feeders in 250.15.B.6. This is saying that no feeder is required to be larger than the service conductors.
I maintain that the feeders to all lighting and power panels, in a dwelling, are main service conductors. A service is the equipment for delivering electrical energy from the serving utility to the wiring system of the premises served.
Service equipment is not a component of the premises wiring system.
I don't care if anyone agrees with me, but put some thought in my statements, and when trashing me please quote documents to substantiate a different perception.
Bob: All dwelling panels are lighting and power panels. The supply to each one is the main power feeder.
Read the paragraph below the one about main power feeders in 250.15.B.6. This is saying that no feeder is required to be larger than the service conductors.
I maintain that the feeders to all lighting and power panels, in a dwelling, are main service conductors. A service is the equipment for delivering electrical energy from the serving utility to the wiring system of the premises served.
Service equipment is not a component of the premises wiring system.
I don't care if anyone agrees with me, but put some thought in my statements, and when trashing me please quote documents to substantiate a different perception.
- Location
- Bremerton, Washington
- Occupation
- Master Electrician
Re: #4 copper wire
Bennie:
"No feeder is required to be larger than the service entrance conductors."
The NEC clearly only allows the increased ampacity to apply to the main power feeder as Pierre states. This issue has been changed in the last few code cycles and its intent is now clear. In some cases the feeder may be larger than the service conductors.
Bennie:
"No feeder is required to be larger than the service entrance conductors."
The NEC clearly only allows the increased ampacity to apply to the main power feeder as Pierre states. This issue has been changed in the last few code cycles and its intent is now clear. In some cases the feeder may be larger than the service conductors.
- Location
- Massachusetts
Re: #4 copper wire
Bennie I did provide a document to substantiate a different perception.
I provided it from the only source that means anything when speaking of NEC rules, the NEC itself.
I am sorry you feel like you are getting trashed, that is what can happen when you intentionally go against the flow.
I respect those that do go against the flow and question things, but if choose to do this you must develop a thick skin.
Bennie I did provide a document to substantiate a different perception.
I provided it from the only source that means anything when speaking of NEC rules, the NEC itself.
I am sorry you feel like you are getting trashed, that is what can happen when you intentionally go against the flow.
I respect those that do go against the flow and question things, but if choose to do this you must develop a thick skin.
jxofaltrds
Inspector Mike®
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- Mike P. Columbus Ohio
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- ESI, PI, RBO
Re: #4 copper wire
Maybe there are two of us that do not understand 310.15(B)(6).
"For application of this section, the main power feeder shall be the feeder(s) between the main disconnect and the lighting and appliance branch circuit panelboard(s)".
Between the main disconnect--- Wouldn't the main breaker in a 200amp panel be the main disconnect?
If so a panelboard after this would be fed by a main power feeder, per the definition stated in 310.15(B)(6).
While I do not have the knowledge of some of the posters, I do have an excellent understanding of the English language.
If there were no main (disconnect)in the first panel I would understand that Table 310.15(B)(6) does not apply.
Mike P.
Maybe there are two of us that do not understand 310.15(B)(6).
"For application of this section, the main power feeder shall be the feeder(s) between the main disconnect and the lighting and appliance branch circuit panelboard(s)".
Between the main disconnect--- Wouldn't the main breaker in a 200amp panel be the main disconnect?
If so a panelboard after this would be fed by a main power feeder, per the definition stated in 310.15(B)(6).
While I do not have the knowledge of some of the posters, I do have an excellent understanding of the English language.
If there were no main (disconnect)in the first panel I would understand that Table 310.15(B)(6) does not apply.
Mike P.
- Location
- Massachusetts
Re: #4 copper wire
Mike Think of a combination Meter socket Main breaker combo outside, inside a 200 amp MLO or main breaker panel.
The conductors from outside to inside would be the main feeders.
Any feeder down line from that first indoor panel will not be a main feeder.
If you killed the power to this second feeder you would still have power at the first panel, so it is not a "main"
Mike Think of a combination Meter socket Main breaker combo outside, inside a 200 amp MLO or main breaker panel.
The conductors from outside to inside would be the main feeders.
Any feeder down line from that first indoor panel will not be a main feeder.
If you killed the power to this second feeder you would still have power at the first panel, so it is not a "main"
Re: #4 copper wire
Bennie,
The key phrase is "The feeder conductors TO a dwelling unit" Implying that there is only one feeder to this dwelling unit. This is made abundantly clear in the NEC Handbook. The first disconnect may be called a "power panel", where the main panel in each apartment is the "lighting and appliance" panel. The feeder from the main disconnect to the main panel is allowed to be sized per 310.15B6, while any other "sub-panels" fed from the main panel, would not be able to be sized using 310.15B6. Such "sub-panels" are fed FROM the dwelling unit, not TO the dwelling unit.
You are right in saying there is no such thing as a "sub-panel" (except those installed in a submarine). All panels are classified as either a power or a lighting and appliance branch-circuit panelboard (408.14). But we all know that it is commonly understood that all panels other than service or separately derived panels are sub-panels.
Bennie,
The key phrase is "The feeder conductors TO a dwelling unit" Implying that there is only one feeder to this dwelling unit. This is made abundantly clear in the NEC Handbook. The first disconnect may be called a "power panel", where the main panel in each apartment is the "lighting and appliance" panel. The feeder from the main disconnect to the main panel is allowed to be sized per 310.15B6, while any other "sub-panels" fed from the main panel, would not be able to be sized using 310.15B6. Such "sub-panels" are fed FROM the dwelling unit, not TO the dwelling unit.
You are right in saying there is no such thing as a "sub-panel" (except those installed in a submarine). All panels are classified as either a power or a lighting and appliance branch-circuit panelboard (408.14). But we all know that it is commonly understood that all panels other than service or separately derived panels are sub-panels.
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