Shop wiring questions / advice requested

[David Wambolt]

I'm seeking some advice from those individuals who have custom wired their shops to support multiple different machines, both 110 and 220 volts. I have a mixed variety of equipment that runs on either 110/220. I also have welding and plasma cutting equipment, so I need 220V power for that stuff. I want to finalize my wiring plans for my 20x24 shop. It's not huge, but I built it myself and it fits on the residential city property. It replaced a 15x24 structure that was a total POS and was literally falling down. I made use of my larger/deep lot and installed dual 12' garage doors so that you can drive a vehicle thru the garage. I'll then have a rear driveway behind the shop big enough for two vehicles or a vehicle and a trailer along with a nice large shed. In front of the shop is a single car driveway long enough to park almost 3 vehicles before the gate that seperates the front yard from the back yard.

Anyhow, back to the wiring. I just had my main house panel replaced with a Siemens 200amp panel that has plenty of space to grow. I went from a 60amp fused service to this (house was built in 1950). I then had a 125amp Siemens 12 position, 24 circuit sub-panel installed in the detached garage/shop fed by a 100amp breaker in the main panel. I have plenty of power coming into the shop to run all of my equipment. The circuits I have drawn up so far are:

1. 120V, 20A, 6 Outlets (General Use, Branched, 12/2)
2. 120V, 20A, 6 Outlets (General Use, Branched, 12/2)
3. 120V, 20A, 1 Outlet Dedicated (Dust Collector, 12/2)
4. 220V, 20A, 3 Outlets (General Use, Branched, 12/2)
5. 220V, 20A, 3 Outlets (General Use, Branched, 12/2)
6. 220V, 20A, 1 Junction Box (1.5 Ton Mini-Split HVAC / Heat Pump, 12/2)
7. 220V, 50A, 1 Outlet (Welder, 6/3)
8. 220V, 30A, 2 Outlets (Table Saw, ?????, Branched, 10/2)
9. 120V, 15A, Lighting (Interior Fluroscent, Attic Lighting, 14/2)
10. 120V, 15A, Lighting (Exterior Front, Exterior Rear, 14/2)
11. 120V, 20A, 3 Outlets (Garage Door Opener, Front/Center/Rear, Branched, 12/2)
12. 120V, 20A, 4 Outlets (Ceiling Drops, Jet Air Filtration, Branched, 12/2)

With the combination of breakers I'm using, that leaves me a few breaker positions open for future growth, though I don't anticipate much, if any.

My real question is, what type of plugs/recepticals are you guys using in your shops? I'm pretty much set on twist locks, but I wanted to be sure before I go purchase them. As for branching the 220V circuits, I'm a one man shop and only use one machine at a time. Wiring wise, this is a pretty basic installation. It's just a lot of wire to run.

Thus far I have completed the rough in of circuits 1,2 and 4. Distance between outlets is about 4'. All of my outlet boxes on the walls are installed. I'm really trying to finalize any drops in the ceiling. I wasn't thinking about any outside of my door openers and Jet air filter, but now that I'm looking at the space it might not be a bad thing to have some places to plug stuff in without having the cords going across the floor. I'll be installing six boxes to run my T-8 fluroscent lighting (6 total 8' fixtures with 24 total 4' T-8 bulbs). I'll have 3 rows, each being 16' long which I think will be sufficient for the space. Any thoughts or recommendations would be appreciated before I continue further rough in. I have a really solid idea of what I'm trying to do, but I figured I might as well ask. I might go "Yeah that's a good idea". It's far easier to run the wiring now before I insulate and drywall in the interior. By the time I'm done, my name will be Mr. Romex.

Thanks!

[Mike Jobe]

Sounds like your shop size and tool mix is pretty much identical to my shop. And it sounds like you have planned it out well. I wired my shop and want to make a couple of points that might help. As far as the receptacles, 110V, I used the normal household plugs and receptacles, with 220V I used the locking plugs exclusively, they are less likely to unplug because of vibration and they are typically larger in size to accommodate the larger gauge wire. I used power poles after I located my equipment in the shop, I didn’t like the idea of having conduit spanning across the floor for mid shop located tools such as my table saw (pain to sweep around). One regret I have was the use of the plastic blue 4 squares in the walls; they are not rigid enough to handle continuous use. In retrospect I should have used the steel 4 squares. Lastly, if you haven’t done this yet bury an independent ground rod just for the shop, I would not depend on the home ground rod due to distance. Good luck to you sound like your having fun.
My 2 cents.

[Ben Grunow]

Garage door openers have to be on their own circuit as far as I know. Other stuff sounds good. Make sure to add some overhead power on retractable cord reels. Working without the weight of the cord is great.

Old Mr. Romex

[David Wambolt]

Thanks guys for the input. I did use the blue plastic boxes, but the ones I got for the 220V outlets attach with four nails or screws and are quite rigid.

I'll probably go ahead and run a dedicated 120V circuit for ceiling wiring to use with cord reels. I just got back from the shop and finished roughing in the dedicated circuit for my dust collector and installed the two power feeds to the switch box for my lights.

As for my garage door opener(s), the front/central/rear outlet arrangement is specifically for them. I have not decided if I'm going to use standard door openers or something like I-Drives. This gives me the flexiblity to plug in the opener at which ever place for just a bit of cost in Romex.

Lastly the mentioning of the ground. My shops sub-panel is 10 to 15 wire feet away from my main panel with a four wire feed, including a very heavy duty ground. So I think I'm okay.

[Roy Wall]

David,

I used the twist locks - based on good recommendations from fellow creekers. two 20 amps and a 30 amp in a little sub panel (garage shop). Like you , one tool at a time with a Cyclone DC running.....

[Rick Christopherson]

It sounds like you've planned this out very well and given it plenty of thought. Do you have any convenience outlets outside the building? I would also put in a quad outlet near the overhead door close to the driveway for use in the driveway.

If you have multiple entrances, make sure to put in 3-way (or 4-way) light switches at each entrance. Also, since your primary lighting is flourescent, you may want to put in a utility light circuit for those quick grab-and-go times, especially if you live in a colder climate.

[Rob Will]

David,

I would consider using 10-2 rather than 12-2 on certain things:
Dust Collector,
Heat Pump,
and......where's your Air Compressor?
All of these items run a lot, start frequently, and could end up being heavier than what you have now. I would also consider taking all of these items to 220V.

On the ceiling lights, I would take that circuit to 12-2 rather than 14-2.

Rob

[Richard Butler]

That layout is better than many homes. How many people are going to be working in your shop at once? 12?

[Bill Brady]

You will want to use standard receptacles on the 120v circuits, but spend a little more and buy good receptacles they will stand up to the pluggin the tools in and out. Also wrap the wires around the screws to make the connections, don't use the push in spring contact these will work loose with time. Remember it will be considered a garage so all receptacle circuits will need to be ground fault protected.

[Bernhard Lampert]

Ditto, what everyone else said. And it looks to be a nice and complete design.
One more caveat: Depending on your location and designation of the building, all 110V DCO's (i.e. all non-dedicated 110 outlets) need to be GFCI.
I just recently completed my shop (well, still need to run final dust collection and compressed air piping). I run all electrical exposed in EMT (3/4') fed from attic space. In the attic everything is run in non-metalic tubing (Smurf tubing) for ease of handling. This arragement allows for later changes/upgrades. Also, I did stay away from plastic boxes...they just don't hold up.
On last comment: I purchased all my twist lock plugs/receptacles for single and 3-phase(L6-30 and L14-30) on Ebay. If you are a bit patient and are buying in bulk (i.e.5 of more) you can still get excellent 'deals'. For example, I bought 10 plugs (L6-30, Nylon, Levition, NIB) for $65 just a couple weeks ago!!
Looks like you will have a really nice shop!
Cheers,
Bernhard

[Rick Christopherson]

I purchased all my twist lock plugs/receptacles for single and 3-phase(L6-30 and L14-30) on Ebay.

Just so you know, the L14-30 is not a 3-phase plug. It is a 120/240 single phase plug.

[Mike Seals]

Lastly, if you haven’t done this yet bury an independent ground rod just for the shop, I would not depend on the home ground rod due to distance. Good luck to you sound like your having fun.
My 2 cents.

Mike, it is not a good practice to run a seperate ground rod in a home enviroment, unless you connect them together with a common cable, usually underground. It sets up possible stay currents floating around in your electrical system. You probably would never notice them, but some of you electronic equipment will.

[Rob Russell]

Mike, it is not a good practice to run a seperate ground rod in a home enviroment, unless you connect them together with a common cable, usually underground. It sets up possible stay currents floating around in your electrical system. You probably would never notice them, but some of you electronic equipment will.

Actually, installing a ground rod at a separate structure is a requirement under the NEC (look at article 250.50), but municipalities definitely enforce that differently.

[Rob Russell]

David,

Your overall wiring plan sounds good. I agree with adding a circuit for an air compressor. I'd also plan on the dust collector being a 240v circuit, so allow 2 slots in your panel when laying out the breakers.

Rob

[Mike Seals]

Actually, installing a ground rod at a separate structure is a requirement under the NEC (look at article 250.50), but municipalities definitely enforce that differently.

Rob, section 250.32 covers this, exceptions are for things just like the shop. As long as the equipment ground is routed to the other panel, no ground rod is required.