For those with a separate and dedicated shop (electrical)

[Axehandle]

What is your power supply requirements?

I am thinking of going with 125A for mine but my list of tools (current and future expected will require 9 220v dedicated circuits.

This includes:

Welder (50a)
Air Compressor (60A)
Table Saw, Band Saw, Jointer, Planer, Mill, Lathe, (all 30A each)
Air Conditioner (30A)

Overhead lights (50A) 8 4 banger 4' fluorescent fixures (T8)

Outlets 5 20A circuits.

[cndamm]

I have a 60 amp subpanel and have never tripped the breaker in the main panel.
Air com. 30a
Table saw 30a
3HP DC 30a
DP, planer 20a,
jointer 20a
router table 20a
miter saw 20a
Disk sander, spindle sander 20a
Band saw 20a
This are the circuits the machines are on.

[Splinter Puller]

Axehandle said:

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What is your power supply requirements?

I am thinking of going with 125A for mine but my list of tools (current and future expected will require 9 220v dedicated circuits.

This includes:

Welder (50a)
Air Compressor (60A)
Table Saw, Band Saw, Jointer, Planer, Mill, Lathe, (all 30A each)
Air Conditioner (30A)

Overhead lights (50A) 8 4 banger 4' fluorescent fixures (T8)

Outlets 5 20A circuits.

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If your the only one working in it you will be more then fine.

[Robert Adams]

125 is fine but I'd go 150 as they can be had cheap in kits with breakers.

I'd go with led t8 fixtures. They can be had for just a little more and they are flicker free start in the cold and typically come in 4100k which id's the perfect color for work spaces. Not yellow or blue just white loght.
You can retrofit existing fixtures to led for 18$ a bulb but it still uses the ballast. But you can buy whole led fixtures for that price.

[Axehandle]

Robert Adams said:

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125 is fine but I'd go 150 as they can be had cheap in kits with breakers.

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Point me in the direction of one of these kits if you would please. I have not heard of the like.

[rwe2156]

Doesn't really matter what other guys have, you have to figure up what your requirements are.

I'm a little confused about some of your specs.

Machines up to 3HP only require 20A 240V/12Ga wire.

Dedicated circuits are nice but not necessary if your not running multiple machines at once. That's a lot of expense, too. I have a 3HP TS, 3HP planer, 8" jointer, drum sander and 18" bandsaw on 1 - 20A circuit my electrician said its fine for single machine use.

I've never heard of lights on a 50A circuit.

I recently put in a 200A dedicated service to my shop. That's more than I'll ever need, but my electrician suggested going form 150 to 200 wasn't a big jump in price so I opted for it.

I suspect going from 125 to 150 is even less of a jump.

Bottom line: don't listen to me!!
Get an electrician to look at your machinery and figure up what you need.

[A Squared]

rwe2156 said:

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I've never heard of lights on a 50A circuit. .

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They are really bright lights

[fredhargis]

My last shop and the current one both have 100 amp subpanels. While that has been plenty adequate (even with the welder) If you have the capacity to go with higher amperage, it really doesn't cost that much more.

[meackerman]

what's your supply line coming in?

you don't need to match the panel size to the sum of all the tools you have.

You need to match it to at least the number of things you might conceivably run concurrently, then a little.

so I could see running the air compressor, AC, lights, table saw & a dust collector (you didn't mention) at the same time. 60+30+50+30+30=200. And you'd want some power left above that.

So it seems like 125 would be too small. but I'm not an electrician.

[Just_Dave]

The issue is not totally about how many amps you need the issue is the number of circuits you require.
Electrical panels are limited to the number of circuit breakers they can have based on the amperage. So the first thing to do is determine your circuit needs. For example
2 lighting
4 120 volt outlet
4 240 volt. (8 spots)
Total spots needed 14
You must also consider future growth, heat(?), any other circuits
Verify that the 125 amp panel will hold the required circuits and you are good.

Once you have determined your circuits look at the maximum amount of current you could draw at any given time. In most case you will find that it is less than 100 amps probably less than 60. Size your service accordingly at that point. What is bigger, your amperage needs or your circuit needs.

When I built my shop I wanted things broken down to dedicated circuits probably a bit more than would be considered average so I ended up with a 200amp panel.
Unlike your 120 volt receptacles where you can have several on a circuit 240 volt are typically sized for a specific item. Therefore 240 circuits start eating up space in a hurry.
Keep in mind that the slim, twins, or split breakers cannot be used for 240 circuits so for every 240 volt circuit you must count 2 circuits. Also most panels limit then number of slims so just because there is room for them that doesn't mean the panel is listed for them. For example my panel is a 30/40. This means I can have 30 full sized or a combination of 40 full and twins.
Personally I am not a fan of the slims so I sized to avoid there use.