Hi.  The electrical in our house is being redone a bit.   This morning I thought, "Hmmm...  Why not add 220V to the shop/garage while we're at it?"  So...

Do you have 220V in your shop?   
Where do you have the outlets?  Walls?  Ceiling?
How big is the circuit?  20 amp?  30 amp?  40amp?   bigger?
How did you run the wires?  Through the studs?   Surface mount conduit?  Other?
Anything to watch out for?  Gotchas?  Tips and tricks?

And finally, if you did it over again, what would you do?   The same?  Different?

Thanks for any feedback,

Dan.

I added one 220 circuit to my garage shop when I decided to buy a cabinet saw.  I was lucky in that the electrical box for the house is on the outside wall of the garage.  I had an electrician do the work so it would be up to code.  He punched a hole in the wall into the box and ran surface mounted conduit to the outlet locations.  I also added two 20 amp, 110 circuits at the same time, as all of the power to the garage shop was 15 amp.  My 220 outlet is located on a wall, directly behind the cabinet saw.  The 220 circuit has a double 20 amp breaker, which is plenty for what I need.  The number and size of the 220 circuits you need depends on what you intend to run on them.

Dan, Try to get the largest gear you can get. If you want to stay in that home and have eonugh power for down the road, 300 amp service with 100 amp for the shop. My condo as most resi has 125 amp panel. I had a double pull 30 amp breaker that was for the dryer. I tapped into the panel form the backside then ran 3/4" conduit to my shop down in my garage. #10 wire and I ran 4 each 30 amp 220v outlets for my TS, RAS, Jointer and one extra. I also added 2 each 20 amp breakers to the panel and ran #12 wire to 14 more 110v outlets in my shop. I have a total of 70 amps not including lighting. I used exitsting single light switch in my shop and now I have 7 each 8' and 4 each 4' double flourescents on one switch. If I ever find the space for my clear vue cyclone then I will go up to a 100 amp sub panel since the cyclone will be 220v and will be running along with the TS, RAS or jointer. Right now being a small one man shop 70 amps is perfect. Good luck and I find electricity is like tools, can never have enough...

As an electrician, and not just a Festool addict.. please keep in mind 80Amps 110volts equals 8800 Watts, and 17600 Watts when your run 220.. 
..and take regard to simultaneous use, 125Amps seems outrageous to me for a 1-2man shop - even if you're running all 110volt equipment and a 4Kw heater on full blow alll the time, you'd still have 9750watts available for powertools, chargers and fluorescents 
(For all 220v the math is 27500Watts total on a 125Amp main.. this is TWICE the normal main breaker size for a std. HOUSE here in Norway - all 240volts..)
Be sure to use 'motor'/reactive/high startcurrent fuses when you do a new install(should be same price), otherwise a 20Amp TS may trip a 30Amp fuse when spinning up..

*PS*
For a nice install and some protection a PVC trunk is nice instead of 'loose', unprotected and dust collecting surface mounted conduits.
Like this type fi. http://special.sut.leon.se/viewpages2.asp?Product=1&ArticleID=563&tree=R21

Also nice for airoutlets btw. - just use a std. reinforced airhose and T's for panelmounting 
Integrated DC may be stretching it, but a 2" hose could be strapped to the bottom, below the trunk..

Wow!  More great feedback!   

mxlars, I've never even seen PVC trunking.  I'll have to take a look at that.

Brandon, there are two circuits that power the garage/shop now.  I'm leaving these in place and will be adding at least two additional circuits.   I very much like your idea of having double gang boxes around the room - two sockets in each box for circuit A and two for circuit B.  That would give me lots of flexibility and plenty of juice.   

Given that it will be much more difficult to add circuits later, I'll go with this - to the two current 120V circuits, I'll add:

- Four 120V GFCI circuits.  Two of the circuits will be run through conduits around the room.   The other two circuits will be stubbed out to a surface mount box for future expansion.

- Two 240V circuits for expansion.   Stub out the circuits in surface mount boxes.

My issue is that I don't have a defined 240V need now, but if I don't plan for expansion, it will be much more difficult in the future.

Regarding your 2 gang boxes, do you run 6 individual wires through conduit?  Romex through walls? 

Thanks,

Dan.

In my Garage/Shop I installed (2) 220 Volt outlets (One on each of the walls 90 degree's from the roll up doors, I run a 60 gallon compressor and Miller 175 Mig Welder with them).  Most of the other outlets are 15 amp service and I added a couple of 20 amp services.  I haven't had a problem with tripping any of my 15's since they are dedicated garage circuits.  The best spot to put the outlets (mine are not this way) is in a covered floor box for tools such as a table saw.  If you ceiling or wall mount the cords become tripping hazards or you'll always be knocking them with your lumber.  When I use my dust collector and saw at some customers homes I have issues with a breaker tripping now and then.  It's because they have so much stuff running off a single circuit in some older homes.  I usually just turn the vac speed down about 1/2 way and can get by.  When you run your 220 amp service install 6 gauge wire which is good for 50 amps.  Don't install a 50 amp breaker though unless you need 50 amps.  If you are going to hookup an air compressor or welder that requires 30 amps install a 30 amp breaker.  The breaker can help protect the tool from a melt down not just the wire in your walls.  For the modest price difference in 10 ga. and 6 ga. wire I'd want the added future flexibility.

Chris... 

Wow!  More great feedback!   

mxlars, I've never even seen PVC trunking.  I'll have to take a look at that.
....
---> My issue is that I don't have a defined 240V need now, but if I don't plan for expansion, it will be much more difficult in the future.
...........

Thanks,

Dan.

That's the beauty of cable/utilitytrunking Dan, when you need more circuits running through it - you just pop off the lids, slip the new cable/line/hose inside, place your outlet(s), trim the pvc lid and snap it back on.
It also give a really clean look, and a slippery surface to remove dust from. 
Some custom outlets for the trunking system may be pricey, then i suggest just using the trunk for the cables and poke a hole with your C12 where you want to place the standard surfacemounted outlets of your choice.
Some systems have plastic dividers for the inside of the trunk to provide some air between heavy loaded cables, or to separate low voltage cables from the mains.

You may have seen this type of light utilitytrunking in hospitals, as they give a cleaner(less messy) environment and they always need some changes done down the road - like special voltage/control outlets, vacuum/pressure, emergency systems, networking different machines and so on.

Depending on the layout of the shop, you may want to run it as they do in some hospitals btw. - from/along the ceiling and down to each toolstation/workplace instead of using it as a rail around the whole room where the precious wallspace is in use 

Dan,

When I added a single bay garage/shop to my house, I had to move the electric entry and service box as well.  So I ended up with a new 200 A main disconnect breaker/switch and 200 A main service panel right in my shop!  From it extend 2 subfeeds each of 100 A capacity to existing service panels in the old and newer sections of the house.  I made a deal with the professional electrical contractor so I could add additional circuits and boxes, and he could check my work before the inspector did.  As others have suggested, I recommend using at least 12/3 with ground to every box so you have the option of 120V or 240V at any box.  You'll need a special 240V GFI circuit breaker to protect this run.  (The licensed electrical contractor was not familiar with this item; I found it for him on the internet listings of Siemens.)  I also had him install a special breaker that will shunt to ground any voltage spikes coming into my house electrical service.  This device installs in the place of a 240V (double pole) breaker or two 120V (single pole) circuit breakers.  I also ran a few dedicated 240V runs to the locations to be used for a central cyclone DC unit, my TS and my compressor.  Some of these are 12/3 w/grd and some are 10/3 w/grd.  I also ran one very short run with 8/3 w/grd (or 6/3 w/grd) into a larger sized wall box and capped it.  That extra HD line could be used with an arc welder, or in an emergency to back feed my service panel with a portable generator.  [For those who are thoroughly knowledgeable about home electric codes, I know this last possible use is not as normally approved.  So far, this outlet box and circuit remains capped is not wired into the panel buss.]  I also set up the lighting so I can turn on any of the three subgroups, depending on what I am planning to do in that garage/shop.  And don't forget about heating that space.

Have fun with your project!

Dave R.

I would never discourage someone from adding a safety feature, but it isn't strictly necessary (according to code) to use a GFI on a 240V circuit.  I've been thinking about it and I can't come up with a situation where you might accidentally short a circuit like this to ground (since 240V is only used with large, relatively stationary power tools).  A 120V, 20A GFCI breaker is $40.  I wonder how much that 240V version is...

You might want to wire up at least ONE outlet without GFI. VFDs (variable frequency drives) don't play well with GFI circuits. Both my Oneway lathes are electronic variable speed and won't run on a GFI circuit.

Do the variable speeds in most of Festool's line constitute VFDs or are they controlled differently?

Brandon,

I like the way you think.   You convinced me!  (I'm so easy!)   As you say, it's minimal risk at worst.

Thanks,

Dan.

I am not an electrician, but I have equpped the workshop/garage in two houses with a 230-240V GFI breaker, and then ran 12/3 w/grd to several wall boxes, then wired some of them so that the upper and lower receptacles were on separate legs of the 230V.  The first was passed by the Summit County Ohio building inspector; the second by the City of Akron inspector.   I am not certain this arrangement meets code, but it has worked for me without any problems, and I have tripped the GFI when cleaning out a sump pump clogged with debris (not a locked armature).  The advantage of this arrangement is two fold: (1) any outlet can be fitted with a duplex receptacle in which each leg can supply 20 A at 120V to a tool or up to 20A at 240V, and (2) when you plug one tool into the upper 120V receptacle and another into the lower receptacle and run them at the same time (as I often used to do running a router and a Craftsman vacuum at the same time), the current losses through the wiring are cut in half compared to normal circuits (assuming each of the two tools is drawing the same Amperage.  For the first garage/shop the double-pole GFI breaker was a special order from Square D, but that was 30 years ago.  For the second garage/shop, all of the service entry and distribution equipment was from Siemens.

The Akron electrical inspector would normally only allow a single 230V outlet on a circuit, without GFI, e.g. for a compressor or dust collector or table saw.  He and the electrician questioned my idea, and each tested it and found everything worked.  I don't know if there are any potential adverse induction issues as can occur when unbalanced circuit legs are arranged inside metal conduct that is grounded.

Dave R.