Feeder size 140' Breaker size

[kest874]

Quick question on wire and breaker size.

Using 2" conduit for entire run from main panel on side of house to sub panel in the garage I'll have roughly 135' to 140' of cable. 2-2-2-4 is readily available in my area.

Would like to go 90 amp breaker, at this distance should the cable be up-sized? or settle for a smaller breaker size?

 

[ard]

Is that AL or CU?

CU looks like you are good for 90.

AL you can run 75

And of course what you SHOULD do depends entirely on HOW MUCH POWER YOU REALLY NEED IN THE GARAGE.

 

[kest874]

Aluminum, mostly wood working but not running a bunch simultaneously. Table saw (240 20 amp) dust collector window a/c unit at most.

 

[mike93lx]

Aluminum, mostly wood working but not running a bunch simultaneously. Table saw (240 20 amp) dust collector window a/c unit at most.

75 is plenty. I'd probably breaker it at 60

 

[wyliesdiesels]

I havent done the load calcs but at 140' with #2 al, 90a load could push the voltage drop past 3%.

But i doubt your load would ever be that high...

Make sure to isolate the neutral bus in your subpanel which usually means buying a separate ground bar. you will also need 2 ground rods...

 

[sberry]

I usually put a 60 cause they off the shelf cheap. I have wired a couple dozen garages, NEVER had one call me back about a trip.

 

[kest874]

I havent done the load calcs but at 140' with #2 al, 90a load could push the voltage drop past 3%.

But i doubt your load would ever be that high...

Make sure to isolate the neutral bus in your subpanel which usually means buying a separate ground bar. you will also need 2 ground rods...

Thanks everyone. Home Depot near me sells the 60 amp and 70 amp breakers on the shelf.

Running 2-2-2-4 mhf with 60 or 70 amp breaker instead of 2/0-2/0-1-4 MHF and 90 amp breaker would save me about $120.

In the GE panel (same brand as the main panel at the house) I'm using I removed the bond between the 2 neutral bars and installed the green bond screw where the grounds will land.

I have 2 8' copper-cad ground rods driven 8' apart connected with #6 CU.

I'm renting a trencher this weekend and installing the 2" inch conduit. I'll measure the feeder run after the conduit install to make sure I'm not over stepping.

Load calc I can't see using more than 35 to 40 amps at once. If I choose to get a welder in the future I can always pull new feeders then if needed.

 

[ard]

Large conduit (within reason) is always better. Remember to toss in some 3/4 or 1" for future use. Low voltage/comms...other stuff...

 

[wyliesdiesels]

Thanks everyone. Home Depot near me sells the 60 amp and 70 amp breakers on the shelf.

Running 2-2-2-4 mhf with 60 or 70 amp breaker instead of 2/0-2/0-1-4 MHF and 90 amp breaker would save me about $120.

In the GE panel (same brand as the main panel at the house) I'm using I removed the bond between the 2 neutral bars and installed the green bond screw where the grounds will land.

I have 2 8' copper-cad ground rods driven 8' apart connected with #6 CU.

I'm renting a trencher this weekend and installing the 2" inch conduit. I'll measure the feeder run after the conduit install to make sure I'm not over stepping.

Load calc I can't see using more than 35 to 40 amps at once. If I choose to get a welder in the future I can always pull new feeders then if needed.

I would check to make sure those are listed to be used like that. Often times they are not and a separate ground bar kit is required.

I prefer to have a neutral bar and ground bar on each side to keep the wiring tidy and prevent wires crisscrossing the panel.

 

[kest874]

I would check to make sure those are listed to be used like that. Often times they are not and a separate ground bar kit is required.

I prefer to have a neutral bar and ground bar on each side to keep the wiring tidy and prevent wires crisscrossing the panel.

Thanks, I'll check that out it's a GE TM3220CCU and I do find ground bar kits available for it. Would definitely make it tidy and easier to work on.

 

[Norcal]

To those who are suggesting a 75A breaker there is no such beast, only 70A or 80A there is price jump going from 60A to 70A, and then another jump in price going for a 80A.

 

[kest874]

To those who are suggesting a 75A breaker there is no such beast, only 70A or 80A there is price jump going from 60A to 70A, and then another jump in price going for a 80A.

Believe the 75 comes from the voltage drop calculator. 60 amp = $10 7 amp = $32 at local Home Depot

 

[kest874]

Attached picture of main panel above, note the ground kit holes on the right. the area I marked red is the bond I removed. red arrow is where the green bond screw was inserted.

Doesn't appear to be ground bar kit installation holes on the left side would you drill and thread some or would you omit that ground bar on the left and still remove the bond landing neutrals on the right side with a ground kit installed as well on that side?


I have 10 or so circuits planned out, this is a 32 space 40 circuit panel.