Electrical decision time and advice requested

[Ken Fitzgerald]

Folks.....I am at the point of starting the electrical rough-in today. I need some advice. My new shop is 30'x24'. One wall has a 36" entry door and a 10' insulated garage door in it. Each of the 30' walls will have 8 120vac outlet boxes. The one uninterrupted 24' wall will have 6 120vac outlet boxes. The 24' wall with the doors will have 2 120 outlet boxes. I am wiring the 120 outlet boxes with 12-3 using the "Edison" concept. What I need advice on is the number of 220 outlets you'd recommend. I am considering 3 220vac in each of the 30' walls.......2 in the uninterrupted 24' wall and one in the 24' with the doors. I am planning on using 10-2 wire for the 220 outlets. The catch is that each of the 220vac outlets have to be on a separate circuit and breaker and takes up 2 spaces in the breaker panel. I am planning to keeping enough space open so that I could add a 220vac 60 amp outlet immediately below the panel, in case I might learn to weld and need same for future use. Any suggestions?

[Steven Wilson]

I would run the 220V lines in conduit, surface mounted once I have the tools placed and then run what is needed.

[Dick Bringhurst]

Ken, have you considered putting a couple of 120 outlets in the ceiling so you can mount self retracting extension cords. They sure come in handy especially over the assembly area. Dick B.

[Ken Fitzgerald]

Dick.....yes I'll place some 120 outlets in the ceiling for that very reason....thanks for the suggestion.....I'd thought about it ....and forgot about it......

[Tyler Howell]

Hey Ken.

I like Steve's Idea. You've heard me rant about conduit. Just because it's run doesn't mean you have to hook it up. As you get use to your shop, make changes and stettle in you may find you'd like another arangement. You've planned ahead, it's a matter of some simple changes. Just make sure you ID every ckt.
Good luck and play safe!

[Wes Bischel]

Ken,

When my dad did the layout for my garage (I was the grunt - he was the brains), he had me run two seperate circuits to each of the quad boxes along the back wall (I used 110 until the 220 was needed). That way when I bought my compressor, I had 220V at any of the boxes. I cannot remember the exact layout, but the inspector thought everything was okey dokie. Maybe one of our resident electricians knows the details.

Just food for thought.

Wes

[Jim Becker]

It's hard to recommend a placement for 240v outlets since they are more dependent on tool location than 120v setups. You may actually need one or more overhead in the future as your tool collection changes. Frankly, some of my 240v circuits have changed location several times over the past five years as new tools were aquired and the shop layout evolved. Keep that in mind since flexibilty is key to that.

BTW, you can have more than one 240v outlet on a circuit, but you cannot daisy chain them. Branch off in a large j-box. But keep in mind that certain things do need to be on a dedicated circuit, such as the DC and the compressor, since they conceivably could be used concurrently with other tools.

[Gary Max]

My bandsaw was drawing to many amps and I had to run a single line overhead for it.
I used 10 gauge wire and made the run straight from to box to the saw. Having the least amount of wire that was a larger size made everything safer. I still had to replace the motor but ended up with a nice outfit.

[Ken Garlock]

Hi Ken.

If I were you, based upon what was done on my shop, I would put 4 240V 20A circuits along the 30' walls. I would decide where I wanted/needed 240V 30A circuits and locate them.

What you need to accommodate all these circuits is to install a sub panel. right next to your current distribution panel. Put a 100A breaker in the main box, and wire in the sub panel with some heavy gauge wire, like #4. Then you should have sufficient slots for all the breakers you will need. Remember, you do not jumper the neutral and the earth ground in the sub panel, only at the main.

Do it right now, and not have to mess with conduit on the walls later

[Steve Cox]

I am actually at the finishing stage of re-wiring my 20 x 25 shop (2 car garage). I would recommend that you sit down and do a plan of where your 220v tools will be and install accordingly. In my shop I have a tablesaw, jointer, planer, bandsaw, cyclone, and air compressor, all 220v. My bandsaw and tablesaw are powered by drop cords from the ceiling and all the others are off one wall in the shop because that's where the tools are. 115v I can see placing evenly around the walls, that's what I've done too. 220v is a different story. As you said each one takes its' own circuit and that takes up room in the box. BTW, because my walls were insulated but the ceiling is not (go figure ) I ran NM cable in the attic and then ran external MC drops from the ceiling. Works well for me.

[Frank Pellow]

...
220v is a different story. As you said each one takes its' own circuit and that takes up room in the box.
...

Ken and Steve why do you both say that each 220v outlet takes its own circuit? That is certainly not what I am doing with my shop.

[Frank Pellow]

I planned very carefully where I would likely place my 240 volt machines both now and in the future. This planning resulted in 3 240 volt ceiling receptacles and 3 240 volt wall receptacles. Then, just in case I am wrong, I added 5 junction boxes wired with 10/2 in other parts of the walls. There is a 2 metre loop of wire behind each of these junction boxes.

[Ken Fitzgerald]

Frank.....the local electrical code inspector made it "perfectly" clear..on my 110v circuits...because it's in a shop I could put 8 boxes....he also recommended using 12-3 and using "edison" circuits to minimize the number of cables needed to wire them. He also made it perfectly clear....I could not daisy chain my 220v circuits as I could the 110v circuits. I suspect as stated by Jim Becker I can use a junction box and parallel the 220 v circuits from there but....I'll ask the inspector before I do it. I'm not sure but this might be a local "interpretation" of the code or a local code thing.

[Steve Cox]

Frank,

It depends on what you want to run. As it was explained to me I could put more than one 220v receptacle on a ckt provided that only one tool would be running at a time or more correctly, that any combination of tools wouldn't exceed the capacity of the ckt just like 110v. Looking at current draw that meant that my cyclone and compressor each had to be on their own ckt. I suppose then that my jointer and planer could be on the same ckt as could my tablesaw and bandsaw but that only saves me two breakers and it doesn't seem worth the trouble. The other thing is that I am very conservative when it comes to power. I like lots of it and having it run far below capacity. Leaves room for expansion.

[Frank Pellow]

Frank,
As it was explained to me I could put more than one 220v receptacle on a ckt provided that only one tool would be running at a time or more correctly, that any combination of tools wouldn't exceed the capacity of the ckt just like 110v...

I agree, but thats a lot different than a regulation saying that there can only be one outlet per 240 volt circuit.