Shop wiring advice

[Cecil]

I'm the last guy to say get an electrician but it sounds like you need some power to the shop. Good advice about panels above but get someone to figure out what you need for a panel.

Don, I have a 100 amp service to the shop.  The previous owners did some automotive work.  They had a large compressor and most of the work was done with air tools.  There are 8 120V outlets covering the 4 car garage, all on one circuit.  The lighting is 4, 8' florescent lights, on one circuit.  I will be adding circuits to the existing panel.  I will us the dedicated 240V, former air compressor circuit for a dust collector.  I will add 2 120V and 2 240V circuits with receptacles throughout.  I may add additional 240V dedicated circuits later, for example, I may buy an air compressor (larger than my pancake).

[Cecil]

IMO a hundred amp panel for most woodworking is overkill unless there will be multiple people working.

(Former licensed electrical supervisor)

Homer, At my last place, I had 2, 20 amp circuits to run my shop, period.  It was fine.  I only plugged the Vac into the same outlet as the tool a couple of times. 
 

The previous owners put a 100 amp service in the garage.  I hear what you are saying, but it already exists!

[TRW]

A couple of months ago, y'all gave me advice about putting 220 in the shop.  Basically I am planning on running 2, 220, non-dedicated circuits, with each circuit having multiple outlets on the wall and ceiling.

As I get ready to do the electrical work, I am looking for advice on the 120.  Currently there is a single 120V circuit feeding all the receptacles in the wood shop.  I plan on adding 2 more.  I know it will take more wire, but I am thinking about putting every third receptacle on a circuit, rather than grouping them, one circuit per area.  My wood shop is a 4 car garage. 

Think, 1 2 3 1 2 3 1 2 3 rather than 1 1 1 2 2 2 3 3 3.

Other than the extra expense for the wire, what are the pros and cons of this.  I know code will make me separate the wires (no more than 2 under a staple, through a hole, etc.).  Thanks.

If you work by yourself, and have more than a few high HP machines, a good starting point is two 220V and two 110V circuits.

Overhead lighting should be on a separate 110V circuit.

If it's just you, I can't really see a need for three 110V circuits and all the third one does is take up valuable space in the CB box.


If you want to run or think you will install a high HP dust collector or air compressor, add extra dedicated circuits for those.

I work by myself in a 26 x 26 garage and have gotten by nicely with one 220V (20 AMP), one 110V (20 AMP), and one 110V (15 amp) circuit for years.

My 220V tools are my table saw, jointer, shaper, and 18-inch bandsaw

My 110V tools are my dust collector, air compressor, planer, mortiser, two drill presses, radial arm saw, 14-inch bandsaw, and the myriad of hand power tools we all have (routers, saws, drills, etc)

The only thing I run at the same time is the dust collector and anything else it's attached to at the time.

My biggest complaint is not the lack of circuits but the location of the outlets.  Reaching the center of the shop can be difficult if all your outlets are in the perimeter walls.  To overcome this I fabricated a special 15-foot long 220V extension cord which allows me to reach out and touch everything.

[panamint]

panamint:

I can glean some good info from that, but I have a hobby shop, in a residential neighborhood.  That looks like industrial wiring to me. 

RE: Receptacles, I believe buying a better quality is the right thing to do.  However, how do I know a receptacle is "spec grade?"  I don't believe just because it is individually wrapped it is better.

The spec grade stuff is the unpackaged cheap ones loose in a bin. You get what you pay for. Buy the best you can afford and you won't be replacing them after a few months.

[Foggy]

I powered all except two outlets through a contactor [an old magnetic starter with 120 volt coil ]with a push pull switch. One push of the button and everything plugged in is unpowered so no danger of someone bumping a switch or me  leaving something turned on. Two outlets hot all the time for battery charger etc.

[BrentDH]

A couple of months ago, y'all gave me advice about putting 220 in the shop.  Basically I am planning on running 2, 220, non-dedicated circuits, with each circuit having multiple outlets on the wall and ceiling.

As I get ready to do the electrical work, I am looking for advice on the 120.  Currently there is a single 120V circuit feeding all the receptacles in the wood shop.  I plan on adding 2 more.  I know it will take more wire, but I am thinking about putting every third receptacle on a circuit, rather than grouping them, one circuit per area.  My wood shop is a 4 car garage. 

Think, 1 2 3 1 2 3 1 2 3 rather than 1 1 1 2 2 2 3 3 3.

Other than the extra expense for the wire, what are the pros and cons of this.  I know code will make me separate the wires (no more than 2 under a staple, through a hole, etc.).  Thanks.

I can't think of any advantage to doing that unless you are convinced you are going to use two adjacent outlets at the same time.  Here is another solution that I used and posted to another question sometime back.  It uses 12/3 wire to do sort of what you are talking about to only two circuits instead of three.  I am directly copying and pasting so it might not pertain 100% to your question but hopefully it will be helpful.

THIS...

I have a suggestion regarding the electrical wiring.  For certain you want to run individual designated circuits to each of your 220V machines.  But I maximized my flexibility for converting 110V outlets to 220V outlets by doing the following.

For the 110V circuits I used 12/3 wire into each box but only used the black or red alternating to each of the 110V outlets.  (The unused hot just gets wire nutted together and passes through to the next box.)  Then I used a double pole, 20 amp, GFCI breaker in the panel.  To switch any outlet in that circuit to 220V I can just remove the 110V outlet and install a 220V using the red and black wires that are in each outlet box.  

Granted this does not create a dedicated 220V circuit as it is still in the circuit with the other 110V outlets and it limits you to the 20A breaker.

AND....

Another thought on the electrical.  If you think you might want to add a 220V machine in the future but don't want to make the outlet 220V until you need to, you can run a dedicated 12/2 20A circuit there and hook it up as 110V.  Then in the breaker panel just make sure you don't trim the neutral wire too short when you connect it to the neutral bus.  Leave it the same length as the hot wire that runs to the breaker itself.  Then leave the adjacent slot open in the panel so you can just replace with a 220V breaker.  That way you have a more useful 110V outlet until you actually need to convert it.  

[Gary G™]

I have a 16' X 32' dedicated building with its own power.
It has 3' tall transom windows all the way around and 6 X 8' 2-bulb lights. The lights are on 2 circuits and 4 switches. 2 switches each control 1 light; 2 control 2.
I can have anywhere from 1-6 of the lights on as necessary.

[Roly]

A couple of months ago, y'all gave me advice about putting 220 in the shop.  Basically I am planning on running 2, 220, non-dedicated circuits, with each circuit having multiple outlets on the wall and ceiling.

As I get ready to do the electrical work, I am looking for advice on the 120.  Currently there is a single 120V circuit feeding all the receptacles in the wood shop.  I plan on adding 2 more.  I know it will take more wire, but I am thinking about putting every third receptacle on a circuit, rather than grouping them, one circuit per area.  My wood shop is a 4 car garage. 

Think, 1 2 3 1 2 3 1 2 3 rather than 1 1 1 2 2 2 3 3 3.

Other than the extra expense for the wire, what are the pros and cons of this.  I know code will make me separate the wires (no more than 2 under a staple, through a hole, etc.).  Thanks.

Get different color receptacles for each circuit.    Brown ,white, ivory are the common colors that way it is easy to see what circuit they are on.  Roly

[TDKPE]

A couple of months ago, y'all gave me advice about putting 220 in the shop.  Basically I am planning on running 2, 220, non-dedicated circuits, with each circuit having multiple outlets on the wall and ceiling.

As I get ready to do the electrical work, I am looking for advice on the 120.  Currently there is a single 120V circuit feeding all the receptacles in the wood shop.  I plan on adding 2 more.  I know it will take more wire, but I am thinking about putting every third receptacle on a circuit, rather than grouping them, one circuit per area.  My wood shop is a 4 car garage. 

Think, 1 2 3 1 2 3 1 2 3 rather than 1 1 1 2 2 2 3 3 3.

Other than the extra expense for the wire, what are the pros and cons of this.  I know code will make me separate the wires (no more than 2 under a staple, through a hole, etc.).  Thanks.

Speaking of Code, by aware that by passing conductors through a box, they count toward box fill.  You can easily exceed allowable fill if you're not careful, especially if putting two straps on one box (like two duplex receptacles).  Larger conduit is fine, of course, but box fill is also limited, like conduit fill is.

I personally only have two general purpose receptacle circuits, with only one running around the perimeter of the shop.  The other serves my utility bench, but it was originally intended for a space heater (basement) that I never ended up needing, as I like it cool, and it never actually gets cold.  So 6 duplex receptacles in 3 boxes over my 8 ft bench is just ducky for my needs there.  Most of the boxes around the shop perimeter have two duplexes.

If you're planning on running a large shop vac along with a machine (for instance), then I would suggest two circuits, with one duplex on each circuit and two duplexes per box, as others have suggested.  

Any large loads that will run concurrent with other loads should, of course, be on their own circuit, regardless of voltage.  Like a big dust collector.  Or furnace/heater/air conditioning.  Or an air compressor.  And lights, which by the way, are considered 'continuous' loads, and as such, must not draw more than 80% of a circuit's ampacity.

240V machines don't have to be on their own circuit if they won't run simultaneously, just as that applies to 120V loads.  I have 6 or more receptacles on a single 20A 240V circuit to serve my TS, lathe, and RAS, none of which operate simultaneously.  The extra receptacles allow me to move things around, though with the DC system getting more and more permanent, things don't change much any more.  And it's legal and reasonable, though it seems to raise eyebrows sometimes.

You can put two circuits with a shared neutral on a two-pole GFCI breaker (called a multi-wire branch circuit), but you'll be limited to 20A since you'd be using common 15A or 20A duplex receptacles, and you can't put them on 25A or larger circuits.  Which isn't a problem, of course, unless the object is to tap 240V from that, as you'll still be limited to 20A.  And you have to use a 2-pole GFCI breaker, not GFCI receptacles, unless every receptacle is GFCI, as MWBC's can't be done any other way (with GFCI protection, that is).

There's nothing wrong with what you're proposing, but I think it's a bit inefficient as far as layout and materials go.  You're not running an industrial facility, with all machines running concurrently, so you don't have to go nuts on the number of circuits.