I want to run wire from the service panel on the house to a 20 ft by 40 ft.
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.
What size wire and breaker box should I run to and install on the barn?
Thanks in advance.
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.
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.
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
As everyone has suggested...run more capacity than you think you
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
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.
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