Garage shop wiring question?

[Alan Tolchinsky]

HI All,

I'm moving into a garage shop soon and wanted to know the best way to wire it? I'll need at least three 220 volt circuits and 6-7 120 v. circuits for lights and outlets. The garaged is already drywalled so I was thinking of using EMT for surface mounting all the electric runs.

The main house panel in the garage with 8-10 empty spaces. Would you still put in a subpanel?

Are there any articles or advise on running EMT from the subpanel to all the outlets/switches/lights etc.? I've run a little of the metallic tubing but always wanted some more advise on using it. Thanks for any info.

[Don Baer]

Each 220V circuit will require it own set of breaker. That will use up 6 slots in you panel. That leaves you 2-4 for your 110 Volts circuit. At least 1 will be for your lighting circuit leaving 1-3 open spaces. I would use two seperate runs for your recpticals meaning you going to use up all of your available circuits. You can use the half size breaker at least for you 110 Volt circuits so you can get by without adding a sub panel but if it not a matter of economics I put one in.

your recepticals should be on GCFI's and I don't believe that they are available in a half height breaker so you would have to use GFCI type recepticle as the first ones on you 110V runs. Again with a sub panel you can buy GFCI breakers.

Since your going to run conduit it might be easier from the sub panel also.

[Kevin Post]

I was in precisely the same boat as you when I wired my garage. I put in a sub-panel. I'm glad I did because it didn't really cost much more, it's easy to add additional circuits if necessary and I can turn off the breakers when I leave the shop which prevents kids from pushing buttons when I'm not around. I used EMT conduit since the garage wall were finished.

[Steve Aiken]

You may wish to re-evaluate your needs for your shop. Don't forget that in a one-man/woman shop, you can only run one tool at any given time. One 220V circuit with multiple plugs may suffice for your woodworking tools. A second circuit for a dust collector will be a great idea--if you don't have one now, you will someday. The only real need for a third 220V circuit would be if you plan on having a 220V compressor plugged in all the time (motor could cut in at any given time while you're operating another tool.

6-7 120V circuits is probably "way-overkill." One circuit will handle all the lighting you can install in your 2 or 3 car garage, along with a few convenience outlets for a radio and such. The same principle applies: you can only use one tool at a time. So...one circuit with lots of outlets around the room for 120V power tools, and a second circuit with lots of outlets around the room for things like battery chargers for cordless tools...should be plenty. You could even combine two duplex receptacles in one quad box, to make it look pretty. Only if you plan to use electric heating, would you require more circuits.

Before you do the subpanel, check out your local electrical supply house. Quad breakers are available for some panels, they take up 2 breaker spaces, but the outside breakers and inside breakers make up the 220V circuit, such that each 220V circuit draws from both "phases."

As far as running the conduit, go to this website and search "running EMT" http://www.selfhelpforums.com/forumdisplay.php?f=12

Steve

[Rob Russell]

Alan,

The fact that the main service panel is in your garage gives you some nice options.

I would install a subpanel and isolate all of the machine and tool circuits to that subpanel. You could get fancy and buy a 2-pole contactor on eBay and a key switch. That would allow you to turn the machine subpanel on and off - and lock it - to prevent kiddies from turning things on you didn't want turned on. This does add some slight complication and cost to the wiring, but it just means getting a key switch, contactor rated for the subpanel current and a utility box to put the contactor/switch in. I just looked at eBay and you could get all of that stuff to lock/power a 50-amp subpanel for under $50. Without spending much time looking, you could do a 60-75 amp subpanel lock/power setup for under $100.

Even if you don't go the contactor route, you could go with a main breaker style subpanel and kill power by flipping the main breaker and locking the subpanel. I like the contactor route only because it means you're not using the breakers as switches.

Rob

[Steve Stube]

Yes plan for the on-demand items such as A/C, Heaters, D/C, Compressor and maybe a dehumidifier (are there others).

At least in the recent past if you installed a subpanel within 6' of the main panel it didn't require a separate main breaker for the sub. I do like the lockout relay idea that Rob mentioned and agree with him in avoiding using circuit brakers as switches. They are not switches but rather a means of disconnect and will not hold up to use commonly associated with switches.

Plan your system (the little electrical premiers are a great souce of info) in advance of stringing any conduit so you are sure to use the correct size. The number of conductors of various sizes that can be run in a given size conduit are found in tables in the "little" book. It's not a question of will they fit but rather will it pass code. The "NEC" is for our own safety.

One circuit for all the lighting (as suggested above) is not the way I would do it nor would it handle the lighting requirements in a 2 car garage shop - at least not at my place. I use a combination of bulbs and tubes for lighting and would have to have two circuits go out before I would be left in the dark operating any power tool. If I loose all power then the emergency (battery) operated lights come on. No recepticles on a lighting circuit is the preferrable way to go. And I mention the battery backup units (I like having enough light to see my way around should I loose power and figure a $20.00 is cheap insurance to do so) because they need a recepticle to pulg into also (up near the ceiling). Ceiling - Alan you may be able to string romex wire up there still and consider plugs, twistloc plugs or cable drops (depends a little on how high the ceiling is) over work areas. Anyway, best wishes with your project.

[Roger Everett]

Allan:
To give you another perspective, this is what I did.
I had a few hundered ft of 10-3 and 12-3 romax already. I wanted to allow for any future circuits I may want to put in, so I got a 125 amp box, for a sub-panel ( because of the amount of circuits it would accommodate ). I ran a 100 amp breaker to sub-panel from main panel. I have sofar run 5- 220 circuits, 1 -110 for lighting , and 1-110 to a box that also has a 220 ( as my planer and sander requires both ), 2- 110- 20amp circuits to outlets around shop ( wherever I might need to plug in including 1 at each corner of my 4X8 TS rec. table and on each side of workbench ). Except for planer and sander ( which I roll out from wall when needed ), every pc of equiptment is pluged in and ready when needed, I don't do unproductive extention cords or unplug 1 tool to plug in another.
I ran 1/2" and 3/4" conduit up the walls to 2-3" above ceiling, then ran the romax thru it and then across attic and down to sub-panel. Doing it knowing, that working alone, I wouldn't be running over 50 amps at a time. Still have 1 50amp 220 to run for welder, been procrastinating that. Even with it I still will have plenty spots for any future circuit I may want.
Roger

[Alan Tolchinsky]

a sub panel. Now I have to look at how to run the conduit and including from the main to sub panel. Right now I have two 220 lines. One of them is shared between the TS and BS. The other 220 is for my DC. In the garage shop I'm going to probably need a 220 line for a heater and another for possible A/C. I'm going to research the links given me here. Thanks again for all the help and guidance.

[Steve Stube]

Maybe the 220 circuit for the heater could be shared (one and the same) with the A/C.