services size feeder

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At that length with 150 amp load you would need a 1/0 cu to maintain a 3% voltage drop.
As far as your "ground" is concerned, a lot of calrification is needed. Terminology is important !! Are you discussing a service or a feeder ? A grounded conductor or an equipment ground ? If it's a feeder and you are asking about the equipment ground, a #6 Cu would be sufficient with a 150 amp OCP device.
If you are asking about a grounded conductor, that's a who different discussion.
 
Does your #6 EGC calculation include any proportional increase in EGC size because of larger than required ungrounded conductors?

Tapatalk!
 
GoldDigger said:
Does your #6 EGC calculation include any proportional increase in EGC size because of larger than required ungrounded conductors?

Tapatalk!
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My #6 does not, but I don't know if his 1/0 would be an "increased size". In some cases, such as where 310.15(B)(6) were not applicable, 1/0 would be the required conductor. The OP lacks a lot of information.
 
michalspike said:
feeder
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Assuming:
  • 2011 NEC
  • 150A service disconnect or feeder ocpd
  • calculated load NC+125%C is greater than 125A
  • qualifies under 310.15(B)(7)
...the minimum size is #1 cu (or #1/0 al)
...the minimum size EGC is #6 cu (or #4 al)

Being calculated load is typically conservative, #1/0 cu (with #4 cu EGC) is probably adequate. If you go with #2/0 cu, the #4 cu EGC is still the minimum required.
 
Smart $ said:
Assuming:
  • 2011 NEC
  • 150A service disconnect or feeder ocpd
  • calculated load NC+125%C is greater than 125A
  • qualifies under 310.15(B)(7)
...the minimum size is #1 cu (or #1/0 al)
...the minimum size EGC is #6 cu (or #4 al)

Being calculated load is typically conservative, #1/0 cu (with #4 cu EGC) is probably adequate. If you go with #2/0 cu, the #4 cu EGC is still the minimum required.
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Smart I dont understand a few things: 1) what do you mean or is the purpose of "calculated load NC+125%C is greater than 125A"? Are you assuming that the load must be over 125 because he is not proposing a 125 amp service? 2) wouldnt minimum AL be 2/0?

IMO he really doesnt need to figure voltage drop at anything over about 60 amps.
 
electrofelon said:
Smart I dont understand a few things: 1) what do you mean or is the purpose of "calculated load NC+125%C is greater than 125A"? Are you assuming that the load must be over 125 because he is not proposing a 125 amp service? 2) wouldnt minimum AL be 2/0?

IMO he really doesnt need to figure voltage drop at anything over about 60 amps.
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Just making assumptions... in that the service/main feeder is sized at 150A because it has to be... somewhat indicating what amount of current the feeder will be handling for the voltage drop cal'... just a different approach to the same conclusion you have regarding 60A for voltage drop... but I'm of the impression 60A is closer to what a necessary minimum 100A service will draw. So we're looking at something closer to 90A... IMO.

And you are correct about minimum size aluminum would be 2/0. (typo :angel:)
 
electrofelon said:
IMO he really doesnt need to figure voltage drop at anything over about 60 amps.
Click to expand...

Are you talking something specific to this installation or just a general statement that is doesn't matter much over 60 amps?:?

I say this because there are three things that are all just about as equal of importance when it comes to voltage drop, Applied voltage, actual current, and resistance of the conductor. Change any of those three and you will change the others as well. OK, applied voltage may not change but voltage at the load will change if you change either of the other two.
 
augie47 said:
My #6 does not, but I don't know if his 1/0 would be an "increased size". In some cases, such as where 310.15(B)(6) were not applicable, 1/0 would be the required conductor. The OP lacks a lot of information.
Click to expand...
I thought the standard size for services in America are
100, 200, 400, 600, 800, 1000.....
but not 150A like his sitiuation
 
Toros said:
I thought the standard size for services in America are
100, 200, 400, 600, 800, 1000.....
but not 150A like his sitiuation
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It depends on the POCO and the history of the area. It is neither an NEC nor an NESC standard, it is just customary.

There used to be a lot of 60A services in some places.
It is true that most POCOs will want to go directly from 100A to 200A when upgrading or offering new service.
The user with a 200A service is then free to put a 150A main breaker in his side of the system.
Some brain dead POCOs like LA DWP will require the user to buy a 200A service if the bus rating of his main panel is 200A, even if he only puts a 100A main in it. I shudder to think about what they do when a user has a main with a 225A bus. Do they require a 400A service?

(This comes into play mainly in grid tied PV installations in LA).
 
GoldDigger said:
It depends on the POCO and the history of the area. It is neither an NEC nor an NESC standard, it is just customary.

There used to be a lot of 60A services in some places.
It is true that most POCOs will want to go directly from 100A to 200A when upgrading or offering new service.
The user with a 200A service is then free to put a 150A main breaker in his side of the system.
Some brain dead POCOs like LA DWP will require the user to buy a 200A service if the bus rating of his main panel is 200A, even if he only puts a 100A main in it. I shudder to think about what they do when a user has a main with a 225A bus. Do they require a 400A service?

(This comes into play mainly in grid tied PV installations in LA).
Click to expand...
NPPD the largest power supplier in NE, requires customer/contractor to bury raceway for underground services from their pole or pedestal to the structure where the meter will be placed - typically on the building served for most applications, but there are some different cases at times. They then pull conductors through this raceway and connect the supply side of meter and of course the source end. They will not pull anything less than 4/0 AWG aluminum conductors, and you will never run anything less then 2 inch raceway. If you are only supplying a 100 amp service you will need to provide a 200 amp meter socket or their 4/0 will be very difficult to land in a 125 amp meter socket.

I haven't run into it but I think if you wanted underground service for a sign or other really light load you still would have to run the 2 inch pipe because they are pulling 4/0 to the meter. They won't care if you only connected a 30 amp service disconnecting means after the meter though.
 
kwired said:
Are you talking something specific to this installation or just a general statement that is doesn't matter much over 60 amps?:?

I say this because there are three things that are all just about as equal of importance when it comes to voltage drop, Applied voltage, actual current, and resistance of the conductor. Change any of those three and you will change the others as well. OK, applied voltage may not change but voltage at the load will change if you change either of the other two.
Click to expand...

(B)(7) got thrown in the mix so I was thinking dwelling unit, but yes OP never stated this. There are exceptions of course, but I find it hard to get most houses/dwelling units up to 70 amps if I try and even if it happens it will be short lived and resistive loads.
 
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