Wire size

[gforster]

What size wire should I run?

POCO is installing 200amp service to my house
meter/main disconnect;
I will run 150amp into house (1600sqft)to a subpanel

Also from the main disconnect I'm running
100amp to a shop building subPanel(140 ft run) ,
Then from this subpanel running 40amp to a small outbuilding (95 ft run)
The wire will be in buried conduit on both runs.

Also, the 100amp is overkill- 75amp would match
to load calcs; thoughts on which way to go?
The breaker panel at shop building is 125 amp rated

 

[sberry]

Run number 2 alum from building to building which is a 90 amp wire and use 100A panels in both out buildings, same wire for both. Use a 60 to feed the second.

 

[Norcal]

What size wire should I run?

POCO is installing 200amp service to my house
meter/main disconnect;
I will run 150amp into house (1600sqft)to a subpanel

Also from the main disconnect I'm running
100amp to a shop building subPanel(140 ft run) ,
Then from this subpanel running 40amp to a small outbuilding (95 ft run)
The wire will be in buried conduit on both runs.

Also, the 100amp is overkill- 75amp would match
to load calcs; thoughts on which way to go?
The breaker panel at shop building is 125 amp rated

75A is not a standard size fuse, or circuit breaker, it goes from 70A, to 80A, 90,100,110,125A.

 

[wyliesdiesels]

How long is the run from meter main to house subpanel?

at minimum u will need 1/0 cu or 3/0 al.

 

[gforster]

House sub panel distance will be only 15ft;

My main concern now is to the outbuildings- conduit size
2" for the 100amp. ?

1-1/4 for the 60 amp( upping from 40 to 60)?

 

[pattenp]

You don't directly size conduit by amps. Number of conductors and conductor size (gauge) determine conduit size.

 

[sberry]

The 60 would be the breaker not necessarily the wire. Number 2 will go up a section of 1 1/4 for a service and it will pull in 1 1/2 if you have to but 2 inch is a lot easier. It may be able to be direct buried also under some conditions. I got 1500 or so ft underground.
The number 2 fits in a 60 breaker and it is cheap, over that the cost goes up slightly or more and often its just not needed. The wire is good for 90 to a panel that is good for 100 and somewhere and someplace someone makes an odd 60 or 40 or whatever but standard panels today are 100 and can be used for less. Homeline may have a ML 6 space for 16$ maybe? The 90A wire cost the same as a 30A wire. Even on long runs this is ideal for power tools and motor starts.
Use the same wire between the buildings.

 

[sberry]

You could run continuous load of 60A at 150 ft no problem down 2 but if you put 40A at the end of the extra 95 ft it makes it near 250 so we don't really want the second wire to be smaller than the first.
As a kind of quick rule I kind of figure at 200 ft the wire serves a load well at half its rated amps. I have 250 ft to my house, has gas cooking and water heater so unless micro is running or using space heater the load is only a couple amps, I think I put it on a 50 breaker. I found 2 70 on clearance and grabbed them but to garages I usually use a 60 unless I know they will be stick welding regularly and have a 5 hp comp.