how many circuits in a shop?

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Forum topic by HokieMojo posted 03-04-2010 09:07 PM 7299 views 1 time favorited 19 replies Add to Favorites Watch
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2104 posts in 3757 days

03-04-2010 09:07 PM

One more electrical question for the day. I’ve read a lot about people adding outlets to their home shops. Some people say they hove sockets every 3 ft. This seems a bit extreme to me, but to each his own.

My question is, how many circuits would most people want. My thinking is that if I have 3 circuits for outlets in my garage, that should be plenty. I could have one for my current tool, one for my dust collector, and one for miscellaneous other things like a fan, stereo, task lighting, plug-in hybrid rollerskates, etc.

I’d also add a 220 for the future for if I ever plan to get more powerful tools. Each of the 3 circuits would have 3 outlets to go with them. the 220 would probably only have the one outlet. I think this would meet all my future hobbyist needs, but I’d like to hear others thought on this..

19 replies so far

View spaids's profile


699 posts in 3722 days

#1 posted 03-04-2010 09:20 PM

I have a garage shop. Everything mobile and everything packed up and put away when I’m not playing. I have just what you described. Two outlets each on their own breaker with nothing else on them. Thats for the one tool I’m running at a time. I have another for my shop vac /dustcollector. Again nothing on that breaker but the vac. And then I have some pull down retractable cords hanging from the ceiling that plug into the the garage door outlets. I never feel that I am out of power or that outlets are too far away. If I had stationary tools I might do everything differently. No matter how many outlets I have, I am going to have to run an extension cord for it and I can’t use more than one tool at a time so more outlets would just be a waste of effort for me to install.

-- Wipe the blood stains from your blade before coming in.--

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Kerry Drake

167 posts in 3049 days

#2 posted 03-04-2010 09:27 PM

I have 3 20 amp 110v circuits in my shop. 1 20 amp goes down the left side of the shop (3 sets of 4 outlets), 1 goes down the right side(again 3 sets of 4 outlets), and one is hooked up to just 1 outlet right near the breaker panel and my compressor gets plugged into that.

I also have 1 15 amp breaker for the lights.

-- Kerry Drake, Loudon NH,

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117128 posts in 3606 days

#3 posted 03-04-2010 09:29 PM

I have ten 220 and Thirty 110.

-- wood crafting & woodworking classes

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661 posts in 3229 days

#4 posted 03-04-2010 09:31 PM

There is more to consider than just the number of circuits to add. You need to take into account whether your shop has its own seperate power or are you adding to the homes service panel. If adding to the homes service, you need to take into account the how much free space you will take away from the house. There are codes for every part of the country and it is based on the National Electric Codes.
I prefer adding a sub-panel to the garage with its own breakers for lighting, outlets and a 220 circuit. I am using a 2 car garage, but only about 2/3rd’s of the space. I have 4 wall outlets and a ceiling drop on 1 20 amp circuit, my lighting is on a 15 amp circuit and a 20 amp 220 volt circuit. All runs out of a 60 amp sub-panel.

-- Methods are many,Principles are few.Methods change often,Principles never do.

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2104 posts in 3757 days

#5 posted 03-04-2010 09:34 PM

Not everyone needs to run 30 routers at a time though. lol

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40 posts in 3050 days

#6 posted 03-04-2010 09:46 PM

When I rewired my garage, I put in 6 quad outlets on a total of 3 circuits with no two adjacent quads being on the same circuit. Lighting is on a separate circuit as is the freezer we have out there. I also added in a single 220V 30 amp circuit. I put it all in surface mounted EMT conduit with surface mounted metal boxes.

As it works out, I have my Drill press and bandsaw sharing a circuit with task lights and chargers. Dust collector/shop vacs are on another, and I keep one cord that I switch to whichever machine I am currently using (table saw, router table, router, etc) plugged into the third circuit. Before setting up machines, I always check to be sure that ‘the’ power cord doesn’t have anything plugged into it.

-- Lee in Phoenix

View SnowyRiver's profile


51457 posts in 3509 days

#7 posted 03-04-2010 09:49 PM

I ran a separate breaker box (60 amp) to the shop off my house box. I am usually the only person working in there. My shop is 21 ft by 21 ft and I have 5 115V 20 amp circuits. Each circuit has a quad outlet. I also have two other 115V 20 amp circuits with just the standard two outlets that I use for the bandsaw, air filter, and shop heater blower. I have two 220V 30 amp outlets. One on each of the side walls. I am currently only using one for the TS. The lights are run off a house circuit. Nothing dims when the equip starts up and is running :-)

-- Wayne - Plymouth MN

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5726 posts in 3261 days

#8 posted 03-04-2010 09:54 PM

I don’t see a need for me to go 220V in my small shop. I am planning on 3 @ 20 amp 110V circuits. 2 of the circuits would get quad socket receptacles, 1 would get a standard 2 socket receptacle (for the Dust Collector / and / or Shop Vac.

Lighting would stay on the existing lighting circuit.

I will be pulling a small 60 amp sub panel into the shop to feed the circuits…

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View richgreer's profile


4541 posts in 3103 days

#9 posted 03-04-2010 10:03 PM

I have 3 circuits. All our 110 volts. One is 20 amp service and the other two are 15 amp service. All of the big tools are on the 20 amp circuit and I never use more than 1 of those machines at a time.

-- Rich, Cedar Rapids, IA - I'm a woodworker. I don't create beauty, I reveal it.

View Dave Owen's profile

Dave Owen

254 posts in 3103 days

#10 posted 03-04-2010 10:19 PM

Hi HokieMojo – I’m always inclined to err on the side of safety and convenience, and since I built my shop from scratch, I have LOTS of receptacles – and LOTS of circuits for a small shop. I like being able to leave most of my tools plugges in – and especially not having to rely on extension cords.

My Grandson just raised the same question to me regarding the shop he’s putting together in a single garage, and I recommended four circuits. Here is the reason. He has two long walls plus a short wall to work with. I thought it probable that he would often use two tools (each with a fairly large amp draw) on the same long wall at a time (say the dust collector and a planer). Another factor was a fairly strong possibility of two people working there at the same time.

In your case, it sounds like you will be working with one long wall and one short wall – and likely relying on an extension cord or two. In that case, three circuits sounds reasonable. If, instead, you’re going to run a couple of overhead drops to some heavy-load tools in the middle of the floor, in my opinion four would be better.

-- Dave O.

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116 posts in 3035 days

#11 posted 03-04-2010 10:32 PM

I found that when running my single stage large dust collector the lights would dim. So when I framed in my basement shop I ended up with five 15 amp circuits not including the lights.

One for drill press, band saw, and a small shopvac.
One for router and small shopvac
One for Large dust collector and lathe
One for table saw and small shopvac
One for drills, jig saw, dremel, etc.

Gosh I didn’t know I had so many small shopvacs. The main thing is to split the load on tools that are running at the same time (i.e., table saw and dust collector).

-- And Still Too Short - "Life is what happens to you while you're busy making other plans." John Lennon

View Alan S's profile

Alan S

181 posts in 3346 days

#12 posted 03-04-2010 10:46 PM

If you’re going to put in 220, I’d put in several outlets for it, definitely more than one. Since I’ve installed 220, I’ve rewired all my main tools to use it and I would hate to have only one outlet for all my main tools.


View grub32's profile


215 posts in 3077 days

#13 posted 03-04-2010 10:47 PM

Yeah, I got a ton of the cheapo shop vacs from HD when they go on sale day after Thanksgiving.

I guess it depends on whether you are putting a panel out there. My friend, the electrician, told me to put everything on a separate circuit till you run out of spaces. That way, you don’t have to worry about overloading a breaker and not getting full power on one of your machines.

I basically have a group of outlets on different circuits so I can put the machine on one and dust on the other. Another for compressor to cycle on whenever it needs to.

I would recommend at least 3…This will work as long as there are no other tools running in the shop.
1 for the machine, 1 for the dust collector and have a third for when you get an air cleaner…All 3 at the same time and plan to have that available even if you don’t have all those dust collectors now.


-- Educator by Day, Wood Butcher by Night!!

View Pdub's profile


924 posts in 3209 days

#14 posted 03-04-2010 11:32 PM

I went for overkill when I wired in my new shop. I have a 100 amp service just for the shop. Each wall is on a separate 20 amp breaker with 4-5 outlets on each. My dust collector and air cleaner are each on a switch controlled outlet and I have two additional outlets in the ceiling. I also have an floor outlet, run through a conduit (because I wasn’t smart enough to do it before the concrete was poured) to the middle of the shop, for my TS.

My old workshop was short of outlets and circuit breakers, so I figured I would remedy that with this one.

-- Paul, North Dakota, USAF Ret.

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Vincent Nocito

485 posts in 3393 days

#15 posted 03-05-2010 12:13 AM

I have three 20 amp circuits, three 15 amp circuits and one 30 amp circuit. The 15 amp circuits are along the two walls where I have my workbenches. The 20 amp circuits are along the two walls where I have tools. There is a 20 amp circuit for ceiling outlets (air cleaner and radiant heaters). The 30 amp circuit is dedicated for my table saw. Right now it is 115 volt but the wire that I ran can be converted to 220 volt service in the future. Outlets are spaced about every 4 feet along the walls.

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