2008 code change? Table 310.15b6

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M. D.

Senior Member
Augie confused me , not that he meant too or that it is hard to do ,..but I now have a question.

So we have a service feeding an outside disconnecting means consisting of two breakers ,, one is a branch circuit feeding an AC all outside. The other is a 200amp breaker feeding a panelboard inside the dwelling the service is 4/0 al what size would the feeder to the panel need to be ??

I see only one feeder so 4/0

FEEDER All circuit conductors between the service equipment...... and the final branch circuit overcurrent device
 

raider1

Senior Member
Staff member
Location
Logan, Utah
Augie confused me , not that he meant too or that it is hard to do ,..but I now have a question.

So we have a service feeding an outside disconnecting means consisting of two breakers ,, one is a branch circuit feeding an AC all outside. The other is a 200amp breaker feeding a panelboard inside the dwelling the service is 4/0 al what size would the feeder to the panel need to be ??

I see only one feeder so 4/0

FEEDER All circuit conductors between the service equipment...... and the final branch circuit overcurrent device

There is only one feeder but this feeder would not be the main power feeder. For the feeder to be a main power feeder it must supply, either by branch circuits or by feeders, or both, all loads that are part or associated with the dwelling unit.

The feeder in your question would not supply all the loads associated with the dwelling unit.

Chris
 

M. D.

Senior Member
O.K. that seems reasonable ,.. in my example there is a branch circuit and a Feeder but no Main Power Feeder as my feeder does not supply the total dwelling load .. thus it cannot be a main power feeder .
Not sure it makes sense but it says what it says. thanks for the help there Chris .

I love this site ,.. the best damned sounding board ever!!!
 

raider1

Senior Member
Staff member
Location
Logan, Utah
O.K. that seems reasonable ,.. in my example there is a branch circuit and a Feeder but no Main Power Feeder as my feeder does not supply the total dwelling load .. thus it cannot be a main power feeder .
Not sure it makes sense but it says what it says. thanks for the help there Chris .

I love this site ,.. the best damned sounding board ever!!!

Your very welcome.

I agree, this doesn't make much sense but it does say what it says.

Chris
 

suemarkp

Senior Member
Location
Kent, WA
Occupation
Retired Engineer
No I believe that you have left part of the statement out. What it says is,
Feeder conductors for individual dwelling units or mobile homes
It doesn?t say all feeder conductors

So now we're back to "to" -vs- "for" individual dwelling units. The 310.15(B)(6) definition of main power feeder uses "to each dwelling unit". I see three choices of words which make sense in the section of "for individual dwelling units..." -- to, for, or in. Using "to" or "in", I'd know what it means. A feeder "for" individual dwelling units isn't obvious to me what it means -- can it only supply an entire dwelling unit or can it be within a dwelling supplying only part of its loads? To me, both are feeders for individual dwellings or mobile homes as opposed to being for a comercial building.
 

jwelectric

Senior Member
Location
North Carolina
It ain?t hard to understand at all.

If I had a panel that supplied nothing but my master bedroom then that panel would not be ?for? the dwelling unit but instead it would be ?for? the bedroom. It would be ?in? the dwelling unit and not ?to? the dwelling unit.

If I had a fused service disconnect at the mail box that supplied another fused disconnect at the corner of the yard that served a panel in the basement then every thing on the out side would be feeders that were coming ?to? the dwelling unit that would be ?for? that dwelling unit and the panel ?in? the bedroom wound still be feeders ?to? the bedroom that were ?for? the bedroom.

Now to make sure that we both understand just what is going on here we need to add ?to? and ?for? together and we come up with ?six?
Looking up the word ?six? I can easily learn what the Latin definition of the word is and then I will have a better understanding of just how bad off this thread has gotten.
 
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