Electrical question

[Dick Keats]

I want to run wire from the service panel on the house to a 20 ft by 40 ft. barn/workshop. Total horiz. and vert. distance 110 ft. Max requirement for 220 V is a 3 HP, 1 ph. table saw and a 2 HP dust collector which will operate at the same time but will start independently of each other.

110 V requirement will be some fluorescent lighting and receptacles to operate the usual electrical tools. Question is: What size wire and breaker box should I run to and install on the barn? Thanks in advance. Dick

[RBM]

Unless you are trying to do a bare minimum job, considering the labor and materials required, I would install at least #6 copper on a 60 amp breaker, and possibly #2 copper, on a 100 amp breaker, for the new stuff you're likely to want

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[John Grabowski]

*I agree. I would not go less than 50 amps. Use at least a 12 circuit panel though I think a 20 circuit would give you extra room for future expansion.

[aemeijers]

Agreed. Most of the cost is labor, even if you hand-dig and do the wiring yourself. Wire at least 150% of what you think you need (or more), if not for you, then for the guy your kids sell the place too. A shop building with plenty of power adds a lot more value than a detached garage/storage building does, and the dollar difference is relatively minor. And put in a subpanel with more slots than you think you need, so you or the next guy can painlessly add outlet strings and lights later.

-- aem sends...

[Wayne Whitney]

Others have suggested at least #6 Cu with a 60 amp breaker. That works out OK for voltage drop. Note that you'll need to run a 4 wire feeder if either (1) you'll have another metallic path between the two buildings, such as a phone line or (2) you are under the 2008 NEC. Also note that you'll need a grounding electrode system on your barn/workshop.

Cheers, Wayne

[Pete C.]

Absolutely do better than the minimum, and put it in conduit as well.

When I repowered my shop that is a similar distance from the house (80' horizontal + 6' vertical on each end), I ran 1/0 copper and installed a

125A 32 space panel in the shop (125A is the largest branch circuit you can run). I do metalworking with welding and plasma cutting so I hit that service pretty hard though in relatively short durations.

[BobK207]

Dick-

As everyone has suggested...run more capacity than you think you need.

Capacity for a 50, 60 or 100 amp subpanel ( 12 spaces minimum since your current usage will consume ~6 spaces).

But if you want to save some $'s in the present and not cost yourself a bundle of extra $'s & work in the future......

run conduit sized for the "eventual" capacity but pull wire for the bare minimum current usage.

I would concur with Wayne comment about the 4 wire feed....but add, just go ahead and do the 4 wire feed that way you'll be new code compliant.

My SWAG guess for your current minimum needs ......looks like 25 amps might do it. But I'd go with at least a 30 amp breaker, which says

8ga wire(?) for 110feet.

cheers Bob