How much is enough power?

[woodrail]

After several false starts, time has come to power up the shop!

My shop is used for general, sometimes unusual, projects. Mostly woodworking, but some metal working has come into play at times.

The wish list includes:
dust collector
Cabinet saw
welder of some kind (no idea)

Current equipment (all 110v)
contractors saw (2hp)
Air Compressor (1 hp)
grinder
drill press
sanders
Wood Lathe
Routers
Portable Planer
Band saw

general tools you see around a wood shop. Nothing surprising.

Other considerations:
30 amp RV wookup
Possibility for electric heat or a gas furnace.

This is a one man shop so the table saw won't be used at the same time as a welder.

Main panel is 200a. I'm planning on running 2/2/2/8 copper 65' to 100a sub panel (220v).

Is this enough power? Am I going to wish I had more? Conduit is plenty big, wallet isn't!

 

[Blk88GT]

Your biggest power load will be heat source.

 

[Stuart in MN]

100 amps is probably more than enough for your purposes (for that matter, 60 amps is probably more than enough) - the one caveat is electric heat. Depending on the size of your shop, if you decide to add electric heat it could take quite a bit of power.

 

[Falcon67]

Ran most all that except the cabinet saw on 60A with no issues. Current shop is twice the sq/ft and runs on 75A. Remove cabinet saw & planer and add mill @ 1HP, remove RV hookup and add 1HP well pump @ 240V, plus 5000w electric heat. 3/4 HP metal lathe instead of your wood lathe. My welder is a 120V unit, max 140A weld current, pulls about 12A so it's just like any other "appliance" in the shop. I also have a 3.2HP 60 gallon compressor (240V). I also have two AC units - 6500 and a 10K, both 120V units. And I run both during the summer if needed.

I used 2-2-2-4 aluminum for about a 100' run and can go to 90A if needed.

The old shop had all the same shop equipment and heater with a single 12K BTU AC unit. With all lights, the mill, lathe, DP, heater, compressor, grinder, belt sander all running I made it to a 49A draw.

 

[pattenp]

You can save a fair amount of money on the feeder wire if you drop back to 90A and use 2-2-2-4 AL Mobile Home Feeder. The last I checked here is was $1.47 per foot. Copper is going to cost 3 times that. I assume the feed to the shop is going to be underground?

 

[Steevo]

100A service is probably plenty, but use a 200A panel to get lots of slots for breakers for dedicated circuits.
I used a 20-slot 100A panel in my shop and filled it before I ever powered it on. Even ended up with a couple of tandem breakers for low-load stuff like outside lights and attic lights, etc.

 

[Gary S]

I have 100amp service in my garage. In winter I run both my 5000w and my 4000w heaters, and still have more than enough reserve for my tools.
I don't see you coming up short with that installation.

 

[Cougar]

My shop is 1200 amps.

The one at home is only 60 amps.

 

[woodrail]

Thanks for the responses. Sounds like 100a will be enough.

The mobile home feeder makes me curious. Is this done often? Seems like you are inviting insurance problems if you use a product "not as indended" and something goes wrong. I've been burned on that before.

It the feeder rated for indoor use? Can it be used in a conduit?

Sounds like a great alternative considering I'm about $6 per foot in copper.

Edit: Just got off phone with supplier. #2 copper is goin for $1.05 per foot, so I'm at about $3.50 per foot.

 

[pattenp]

The aluminum MHF is a direct bury cable but needs to be in conduit when exposed above ground or when used inside. Mobile Home Feeder is just a trade name. It is widely used for feeding sub-panels in outbuildings. Be aware of the feeder wire type you use because some of it is not approved for use inside because of not having fire resistant insulation.

Edit: Technically #3 copper is all you need for 100A.

 

[Jefe]

Here's another vote for the 2-2-2-4 "mobile home feeder." That's what I used, it was cheap, easy to find and easy to install. I checked with my inspector that I could go all the way up to a 90a breaker (I have a 60a in there now) and his response was "sure, but you'll have a really hard time maxing out that 60a."