electrical outlet spacing?

[dbarr15]

My shop is 20X12 feet. It has no electric yet. What would you suggest the spacing be for the 110 and 220 volt outlets. I would like to keep all options open and flexable so I can move around and setup tools at will, all tool except the tablesaw will be mobile. Thanks for your input Doug

[crokett]

Most recommendations are to put the outlets so the bottom of the outlet is 4' above the floor. This way you can lean sheet goods up against the wall and still get to the outlets. For practical purposes, I got done with the rough-in wiring on my shop a few weeks ago and put most of the outlets lower than that because I know I am always going to have either tools or cabinets there. The one corner where I know will be lumber storage there are no outlets - that might be a mistake some day. As for spacing, I have them spaced about every 4'. I did double gang boxes and will have each receptacle in the boxes on a different circuit. For my 220V I only put them down one side of the shop. Again, it might be a mistake some day but as far as layout goes the tools that will use those won't be all that mobile, if at all. Where the cabinets/bench top will go I will use power strips so I can plug smaller hand tools in anywhere along the bench. I also roughed in a receptacle in the ceiling so I can hang my retractable extension cord for overhead power when using my assembly table.

[schloff]

If you are able, put one at every wall stud. (slight exaggeration) And I agree, you want to keep them over 4' from the floor. Less bending over, and as previously mentioned, storing of sheet goods is a no brainer.

[JR]

Putting them at every third stud will not be too much. You'll be surprised how readily they will get used, once you hook up a makjor tool, a work light, a radio, and hand-held tool, then poof, you're looking for another outlet.

I like your idea of starting with a blank sheet of paper and just throwing in the outlets, like a commodity. I don't know if you've done a layout yet, but sometime soon you're going to have to do one. I might help to have a rough plan before you commit to the electrical installation. You don't want to have an outlet located behind a cabinet or some such basic mistake.

JR

[BobSch]

I don't know if this meets code or not, but a friend ran all 12/3+ground to all his outlets, then split the hot side so each outlet of a pair was powered from a different breaker. He said the advantage to this was that if he needs 220, all he had to do is switch out the outlet and wire the two hots to it.

[Mr__Bill]

Don't over look putting outlets in the ceiling that are not on the lighting circuit. Pull down cord reels can be real handy. Even an extension cord dropped down to a work bench is better than walking on power cords stretched across the floor. If the shop has a wooded floor and you know where the table saw will be located an outlet in the floor servicing the saw will again save you from walking on it.

While an unlimited number of receptacles sounds like a good idea, be aware that if this install is going to be inspected many inspectors will limit the number of receptacles in non living spaces on a 20A circuit to 13. (This may be local code or just the inspector's judgment, either way it's the inspector's call.) That amounts to 6 duplex receptacles per circuit. You should also stagger them so that if you have a shop vac and a table saw running at the same time they are on different circuits. I have seen people use different color receptacles on each circuit to help keep the load balanced visually. Dedicated circuits should also be planned. I know this means that some idea of layout is necessary and you are likely leaving things flexible to allow you to work out what is the best layout for your tools, but you should decide now where tools like a compressor, dust collector, table saw, arc welder and of course the shop fridge will be located and run dedicated circuits to those places. If you are going to have any heat or AC locate those units now for dedicated circuits too.

Spacing every 32 or 48" should be enough for the 110V outlets with a few 220V added to the mix. Setting the box so that the bottom of the cover place is more than 48" off the floor as stated earlier is a good idea.

If your shop has a door larger enough to get a car into a local inspector may treat it as a garage and require GFCI protection on receptacles that are not single dedicated outlets located less than X feet from the door. While GFCI devices make things a lot safer they also add to the cost. Personally I have all the duplex receptacles in my garage shop on GFCI protected circuits.

While you are running the wiring, figure in the lighting too.

Bill,
Been there, done that, regretted a lot of it...

[Eric]

I'm going to be putting in 1 outlet every 4 feet on the wall, and dispersing my 220 where I think I'll be having my 220 tools. Each 220 will be a dedicated run, and have 2 or 3 circuits in my main tool area with every other outlet being on separate circuits.

Having the outlets 4' off the floor is also very nice. When I was in my garage workshop, I had 2 circuits one each side of the shop it worked out ok, but having a saw and shop vac on the same circuit could be problematic.

[Uncle Cracker]

All the outlets I've ever seen are only spaced a couple inches apart...

[SCBob]

I agree with Mr Bill. I was going to say 32-48" with GFCI in front.
Welcome aboard.

[LarryG]

Some excellent advice in this thread. I'll mention a few more things that I'm not sure have been covered, unless I missed them:

1. Even in a small shop, it's a good idea to have the lights split across two circuits. That way if one breaker trips, you're not left totally in the dark.

2. Dedicated circuits for big stuff is a good idea, but you don't have to get TOO carried away with this. In a one-man shop, where only one tool is in use at a time, every outlet effectively becomes a "dedicated" outlet. (This excludes things like the dust collector and air compressor, since those could be running simultaneously with something else.)

3. If you have fluorescent lights (as most shops do), try to feed them from one leg of the panel while feeding the heaviest motor loads from the other leg. This will minimize momentary dimming of the lights during the initial high-amp draw of a starting motor.

4. On the subject of outlet spacing, I heartily concur that more is better (within reason, and subject to the limits Mr Bill mentions). When you have to run Romex all the way to the far corner of the shop to serve an outlet there, it costs very little extra to insert several more inline along the way.

[crokett]

Oh one more suggestion that I didn't see - wire everything with #12 wire. This way if a light circuit ever needs to be repurposed for an outlet, it is there already and all you need to do is change out a breaker. My light circuits are wired with 14, but that is because that is what the shop was wired with before I moved it. Also wire at least one of your 220V with #10 or wire a separate one with #10. That way it is good up to 30A and can power A/C or small heater. I wired one with #10. Not real sure what it will be for, yet, I just wanted to have it.

[conwaygolfer]

Outlets

I am not sure if it has been mentioned yet, but instead of a single outlet box, I used double gang boxes. That way I always have room for something else when I need it plugged in. Most likely, you'll never need to unplug one tool in order to plug in another tool.

Conwaygolfer

[Tom Slick]

To add to Conwaygolfer's advise, make sure to buy the extra deep boxes, that way there is always plenty of room for future changes.