220v service... any advice?

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Forum topic by buffalosean posted 03-07-2009 03:39 PM 3799 views 0 times favorited 27 replies Add to Favorites Watch
View buffalosean's profile


174 posts in 3591 days

03-07-2009 03:39 PM

Topic tags/keywords: question

I am going to run 220v service out to the detached garage. I am going to set up a seperate breaker panel out there. I was planing to set the 1 1/2 horse vac system (currently ordered) on a seperate line as well as my tablesaw and bandsaw. Someone suggested I put my lights on a seperate line so if I blow a breaker I’m not standing in the dark.

If anyone has any further suggestions or problems they have run into that I should try to aviod, I’d appriciate the input.

thanks, sean

side note. I do have a licenced electrician coming out to help me wire it up.

-- There are many ways to skin a cat...... but, the butter knife is not recommended

27 replies so far

View dalec's profile


612 posts in 4092 days

#1 posted 03-07-2009 04:23 PM

Hi Sean,

If you are planning to put in a sub panel in, you might look to the future and anticipate what power tools you will potentially have in the garage. you should be able to run your dust collection at 110V or 220V. Your band saw may give you that option as well.

I had not thought about it until now, but going 220V cuts amp demand by 1/2 over running the same equipment at 110V. Affecting the amp sizing of your sub-panel. I think I am right on this?

Having a separate 15amp circuit for lighting is a good idea.


View sIKE's profile


1271 posts in 3958 days

#2 posted 03-07-2009 04:42 PM

I built my shop in 2007, and I did 95% of the electrical work myself. Your budget really dictates what you are going to do. The more circuits the more copper you need.

Sit down and do your capacity planning aka how many amps of service will your sub provide? How many 110v outlets do you need/want, do they need to be on different circuits? Same thing for 220v. Lighting on its own circuit.

Be sure to plan all of your equipment and their approximate locations and make sure an outlet is near by. Think about Dust Collectors, Table Saws, A/C units, Air Cleaners, Air Compressor, Electronics/Stereo/TV/PC and of course ceiling fans. I also ran a couple of outlets outside for convince and a couple in the eves for Christmas lights….on a GFI of course.

Hope this helps.

-- //FC - Round Rock, TX - "Experience is what you get just after you need it"

View TheHarr's profile


118 posts in 3743 days

#3 posted 03-07-2009 04:46 PM

Sean, I’ve wired a couple of shops. Here is my suggestion.

1 – 15 amp circuit for spot lights over your work bench. (You need lots of light).
1 – 15 amp circuit for fluorescent lights for general shop lighting.
1 – 20 amp 110V or 220V circuit for your dust collection system.
1 – 20 amp circuit for shop outlets to power your tools.
1 – 20 amp 110V or 220V dedicated circuit for your table saw

If you have an air compressor, put it on it’s own circuit.
If you are planning on buying a compressor in the future, get a 220V set up.
It may seem excessive now, but MAN you will get hooked on it big time. I love
using my spary guns and pneumatic equipment. It will spoil you.

Good luck and get back to me with your final setup.

-- The wood is good.

View Craftsman on the lake's profile

Craftsman on the lake

2832 posts in 3641 days

#4 posted 03-07-2009 04:55 PM

I found this interesting. I have a couple of 20 amp circuits 120v for my shop. I figure that I won’t be using more than the dust collection and one power tool at a time so I won’t go over 20 amps with two circuits. And, for the most part that’s true. But, when I get out to the shop and it’s 20 degrees, turn the gas on to warm it up to about 70. If I need to fire up my table saw while it’s cold (and am running the radio and dust fan) the circuit breaker will sometimes flip. After I’ve run the saw it doesn’t do that again. I don’t know If I’m the only one with this issue, and I suspect I’ll need a new breaker down the road but as far as I’m concerned 12/3 or even 10/3 wire and multiple circuits are not overkill.

-- The smell of wood, coffee in the cup, the wife let's me do my thing, the lake is peaceful.

View TheHarr's profile


118 posts in 3743 days

#5 posted 03-07-2009 05:08 PM

The circuit breaker is kicking off because the motor spikes the instant it is turned on.
In other words, the motor draws higher amperage the instant it is turned on. You can
replace your breaker with a slow-blow breaker. It will accommodate for the spikes in the circuit.

I guess I’m complacent about running extra circuits because I have years of expierence wiring houses
for myself and friends. Whatever—good luck. Ask questions so you don’t do the 110V boogie. The
220V boogie is even more fun. Avoid it.

-- The wood is good.

View JimmyC's profile


106 posts in 3606 days

#6 posted 03-07-2009 05:09 PM

I agree with what has been said, but have a few things to add. If you are running the power out to the shop make sure that it is at least 60amp/ 220v . Make sure that you use a box with at least 12 slots (220v breakers each use two slots) and more if possible. If you are a one man shop this will probably be enough, I ran this system and had lights on, with a 220v tablesaw and dust collector and a 220v air compressor occasionally kicking off and never had a problem. But if you can afford it run a bigger service (100-200 amp) and a box with as many slots as you can afford. You may not use the power now, but it’s nice to have it available. Also make sure that your load is balanced when installing the breakers, as you do not want to take too much power from one side of your breaker box.

Good Luck.

-- -JimmyC...Clayton,NC- "Just smile and wave boys, smile and wave"

View 8iowa's profile


1587 posts in 3965 days

#7 posted 03-07-2009 05:31 PM

In ‘07, when I built my “Workshop in the Woods”, I installed both incandescent and T-8 electronic ballast fluorescent fixtures on the ceiling. They each have separate 15 amp circuits. The nine fluorescent fixtures are switched in three zones. This gives me a very high color rendering index (CRI). I also have a separate 15 amp circuit for the loft, serving two light fixtures. A separate 20 amp recepticle in the loft can be used for occasional rough cuts up there with a circular saw. It is wired in with one of the wall circuits below.

On the shop walls, there are 20 amp 120V recepticles every five feet (approx) on three separate circuits. I put the recepticles 42” high off the floor. The third 20 amp circuit is in a small closet under the staircase. this space can accomodate a small “pancake” type compressor and a modest size dust collector.

Since one of my Shopsmiths is wired for 240V, I have two 30amp 240V recepticles on opposing walls. They are on a single breaker, but are wired so that I can install a separate breaker for each in the future if needed.

Outside in front, where I have an 8’ x 24’ concrete apron, I have an outside 120V recepticle, so I can do some work outside on a nice day.

Since I was actually moving the electric meter from the house to the workshop, my breaker box in the workshop also feeds electricity to the house. This involved an underground splice, and will save me money through the years. I’m capable of doing some electrical work, but this was a job for a licensed electrician.

Most of this can be seen in pictures on my home page blog.

-- "Heaven is North of the Bridge"

View mnguy's profile


201 posts in 3602 days

#8 posted 03-07-2009 11:05 PM

My shop is in the basement on a subpanel. Based on space, I don’t anticipate any tools that requre 220 V, so I ran one 15 amp circuit for lights and two 20 amp circuits for outlets. I put the outlets ~every 4’ around the room, and alternated which circuit they’re on, and I still need an extension cord half the time! So, put in lots of outlets. Consider a couple of electrical drops over bench areas, etc.; it could save you tripping over cords.

One other suggestion; run a floor outlet for the TS.

View SilsbyWoodworks's profile


11 posts in 3577 days

#9 posted 03-07-2009 11:20 PM

Great advice everyone. I did notice though no one talked about what gauge wire to run. Buffalosean just make sure the wire you run to the breaker and to your respective tools in in check with the amperage you will be using.

View Padre's profile


930 posts in 3693 days

#10 posted 03-07-2009 11:43 PM

Absolultely Silsby, good point. I have run mostly 12g 20a to my machines, but my compressor took 30a because of the start up on the dang thing.

I have 4 220v outlets in the garage/shop. I wish I had five.

Also, you might want to make a 220v extension cord with at least 20a wiring, in case you decide to move a tool and then the original cord doesn’t reach.

-- Chip ----------- 6:8

View Bahremu's profile


21 posts in 3606 days

#11 posted 03-08-2009 12:04 AM

I’ll assume you will be running copper wiring for the power. The current draw determines the gauge. In general you can follow this guide:
15 Amps = 14 gauge
20 Amps = 12 AWG
30 Amps = 10 AWG
40 Amps = 8 AWG
60 Amps = 6 AWG

Now to qualify the above. This was taken from the Canadian Electrical Code (1998), Part 1, Table 2, Column 1 and Column 2: Allowable Ampacity for not more then 3 copper conductors in a raceway or cable—based on a 30C (85F) ambient temperature and a 60C (140F) allowable temperature rise.

Remember when you plan your circuits that you should only load a circuit up to 80% of its breaker rating. I always add a receptacle in the ceiling on the lighting circuit—in the event that the plugs all die, i still have one to get power from.

View TopamaxSurvivor's profile


18394 posts in 3880 days

#12 posted 03-08-2009 12:09 AM

What gauge wire to run, for what? The sub panel or the outlets or tools? For the sub panel, i would probably go at least 100 amp. Voltage drop is the big bug-a-boo that makes your lights dim and power tools run poorly. In a shop, I wouldn’t wire anything smaller than #12, except maybe the lights on a separate circuit. Single phase motors draw a lot of juice!

-- Bob in WW ~ "some old things are lovely, warm still with life ... of the forgotten men who made them." - D.H. Lawrence

View buffalosean's profile


174 posts in 3591 days

#13 posted 03-08-2009 12:25 AM

Thanks for all the advice.

i thought about having only 3 220v outlets. but I think alot of you are right. I’m probably should do one or two more.

the vac, table saw, and bandsaw are all 110/220. I figure if I can make them 220v, i’m probably better off making the switch.

I have a month to decide. I”m glad i have a licenced eletrician coming to help me set it up. I do know how to wire outlets and fixtures. but with this project I’m getting into subpanels & 220v, I’d rather have a licensed guy come out, who is a friend of the family.

I’m pretty good on 110 volts, but i do like the idea about having a couple electrical drops…. that would be convinant.

thanks again

-- There are many ways to skin a cat...... but, the butter knife is not recommended

View oldwoodman's profile


137 posts in 3602 days

#14 posted 03-08-2009 03:11 AM


I just did what you are about to do. The distance from the main panel at the house to the sub-panel that I was installing in the garage was 150 feet. I put in a 100 amp panel in the garage with the idea of having a 30 amp 220 volt circuit for the table saw and two 20 amp circuits for other uses. My brother-in-law, who knows electrical wiring from his years in the business, told me that I needed to use 6 guage wire from the house panel to the garage subpanel. He advised me on all of the details as I did the work. The end result is that everything works perfectly. You will never regret this upgrade to your shop.

View Karson's profile


35149 posts in 4604 days

#15 posted 03-08-2009 03:29 AM

I would also agree with OldWoodMan. Putting in a 100 Amp sub panel. That way you have lots of choices in the way you go. Ususally you won’t have all 220 Volt lines active at the same time. So you can put in more seperatecircuits without the concern of overloading. You would want to try to identify those circuits that would be on at the same time. Saw and dust collector, or jointer and dust collector or planer and dust collector. But, probably not saw, jointer, planer and dust collector at the same time.

Knowing the combinations will make sure you are not getting into the overload condition.

-- I've been blessed with a father who liked to tinker in wood, and a wife who lets me tinker in wood. Appomattox Virginia †

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