# New Shop - Electrical Thoughts



## WoodZenStudent (Mar 25, 2021)

Shop is 16×40. I plan to use 1/3 for storage (side-by-side, sled, snow blowers). I'm a hobbyist and never setup a shop before but I'm not looking for perfection; I do want to get started.

*Dedicated Circuit:* Lighting, Heater (gas), Dust collection (20 amp?), Compressor?

*Shared Circuit:* Media blaster, Router, Table saw (20 amp), Planer, Jointer, Sander, Miter saw, Drill press, Band saw

Outlets every 4'; 50" high
Double-gang box where 220v planned; half 220, half 110

Is there any reason to use 15amp or just use all 20amp? If so, what should be 20amp?










Thoughts?


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## bondogaposis (Dec 18, 2011)

Put some outlets in the ceiling so you don't have extension cords across the floor. Outlets on the wall should be higher than 48" so you can lean a sheet of plywood on the wall without blocking the outlets. Wire in lots of lighting.


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## WoodZenStudent (Mar 25, 2021)

Bondogaposis, I thought about hanging from the ceiling but have a high gambrel ceiling. Maybe I can just run a stud across and mount it to that.

Good point on the lighting. I'm still researching the different types and how much/many I'll need.


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## ibewjon (Oct 2, 2010)

All 20 amp. You will never wish for a 15 amp circuit. And at least two lighting circuits in case one trips you won't be in the dark with a machine running. Dust collector, run 30 amp 240 volt circuit. Separate for heat. For a floor box you need a box rated for that purpose. All 120 circuits for tools need GFI protection.


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## Kudzupatch (Feb 3, 2015)

I have always run 20 amp circuits on all outlets. Probably not needed but the extra cost isn't much and I never have to worry about overloading the circuit. You may end up with a higher HP tablesaw or some other unforeseen machine. My thinking is I never regret going bigger but have regretted smaller.

Going to be building a temporary shop to use for the next year or two and I will pull 20 amps and LOTS of 220v. I run everything on 220v that will work on it. Find myself needing more outlets in my current shop.

Going LED lighting but I am going to use standard Edison bases and screw in LED bulbs rather than something proprietary. Easy to swap out with a bigger bulb if needed and I think cheaper in the long run.


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## MadMark (Jun 3, 2014)

Use quad boxes for four outlets per drop. Use 2x circuits so each box has a duplex outlet on separate circuit.

GFCI breakers required.

#12 to tools, #14 for lighting. 2x lighting circuits on opposite phases.

TS on dedicated, not shared.

I use twist-loc connectors on saw and DC, just because. It prevents kick outs and makes sure tool can only be used on its "personal" outlet, preventing unexpected wiring changes.

Put a switch and outlet in one box on bench. Allows easy off/on control at the outlet. I use a switch with built in light 'cause its cool and gives me an easy visual indicator.









Indicator Switch


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## ibewjon (Oct 2, 2010)

Use 12 for lighting as well. 14 is a waste. Add a box for an in wall timer feeding a double duplex receptacle for plugging in chargers. You can hit the 60 minute button and after charging, power goes off so not running when out of the shop.


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## wapakfred (Jul 29, 2011)

For the lighting, consider wiring in outlets across the ceiling, then use LED fixtures that plug in. If one goes bad, you just swap it out. The outlets let you add more later if needed and you can rearrange easily as needed. The LED fixtures ('m suggesting 2 lamp, 4' long ones) can also be daisy chained up to a certain number…usually 4-6 depending on the exact fixture.


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## ibewjon (Oct 2, 2010)

Another option is the porcelain or plastic keyless lamp holders There are many nice edison / standard medium base led lamps, with some fairly high lumen outputs. Also easy to replace if one should fail.


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## CaptainKlutz (Apr 23, 2014)

Solid advice above.

+1 All 115v GFCI protected outlets should be 20A. 
But then 115v circuits are easy part, sort of?

Suggest you take some time to consider the layout of your shop 'work zones'.

Unless the shop is commercial operation, with multiple users operating all outlets all time; most shops daisy chain (or alternate) wall outlets every 4' along a wall. This allows a tool/bench to have access to 2 different 20A circuits on each side. An 8' bench would likely have access to 3 wall circuits, so you might want to alternate 3 circuits around each work zone, at least that is my preference.
How many actual circuits you really need depends on how many tools would be running at same time. Which only you can determine. IME in a one man shop, most folks only use 2-3 120v circuits per 100-250sqft work zone; not including dedicated circuits for head lighting, door openers, or battery charging stations. 
Best examples are hand held router with a shop vac and work light, or 1.5HP contractor saw and 1.5HP dust collector.

Planning 240v outlets is much harder IMHO. 
It requires knowing what equipment and/or motor sizes will be used in shop, and where.

Why? Circuit purpose and motor size is important.
Continuous use welders and/or electric heaters have different rules than motor circuits.
Lets look at motor circuits:
NEC 430 code (which most US building codes follow) requires MOTOR circuit rating to be 125% of FLC (Full Load Current) from code tables. 
FLA (Full Load Amps) on the motor name plate is not exact same rating as FLC. FLA is used to size overload protection for motors. FLC is used for circuit rating. FLC is almost always higher than FLA name plate rating of modern high efficiency induction motors.
Examples: 
2HP 230v motor has 12A FLC = 15A circuit.
3HP 230v motor has 17A FLC = 21.25A min circuit. Next largest protection is 25 fuse or 30A breaker.
5HP 230v motor as 28A FLC = 35A min circuit. Next largest breaker/fuse is 40A.
So what size 230V circuit do you pre-wire in the shop? :-(0)

Motor circuits can be very confusing: My TS manual with 3HP motor with 15A FLA shows a 20A 230v circuit required. Do we really have to follow the FLC code tables?? Short answer - yes.

Most modern WW tool manuals suggest use of 20A circuit for 3HP, as they also specify a lower 14-15A FLA on name plate. These tools will work fine with 20A 230v circuit; unless there is start up surge or locked rotor condition. Without the larger circuit, will experience nuisance trip in severe locked rotor or high torque start up conditions. Both of which rarely happen with wood working tools; unless something is wrong with tool/motor. 
Since your building electrical inspection only inspects the circuit and wall receptacle ratings; can sort of ignore the code. But I don't recommend it. Insurance companies will not pay damage claims when building codes are violated.

The above codes seem to make the universal 230v circuit size as 40A for home shop? Maybe. 
As long as your 230v motors all have properly sized motor starter with overload protection, can safely run any 2-5HP motor on 40A circuit. But at same time, it is expensive to install the larger copper wire and receptacles when not needed. Have you priced copper lately?

Bottom line: Need to carefully consider your work zones, and tools that will run inside each one.

Most serious wood working shops have several zones: Compressor/dust collector zone (noisy closet), wood working zone, finishing zone, and storage zone. Each one of these has different power needs.

Best luck on your adventure.

If any of the above is not understood, please hire a professional.
Be Safe, not Sorry.


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## JCamp (Nov 22, 2016)

If I was building fresh I'd have a few lights that run on solar with a small battery bank so that even when the electric is out I could mill around in there without a flash light. Maybe some ceiling skylights too. 
For traditional lights I used LEDS cause they are nice and bright.


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## tvrgeek (Nov 19, 2013)

I went to a 5 HP dust collector, so 30 A. is spec. Breaker does not need to match peak inrush. They are designed for that. 3 HP on a 20A. 1 3/4 HP on a 110 can run on a 20A. 
Technically any 20A or higher tool should have it's own breaker. My mistake not putting in a big enough service panel. I have the amps, not the slots. Often 30A should be hard wired anyway. If you have a locked rotor, you WANT the breaker to trip.

My bias, but wire size is MINIMUM code. It is smart to actually go one size larger. I would run 10 gauge for all the 20 amp lines. All the outlets should be 20A. No reason to run 15's. If you do need to pop in a 30A breaker, you are OK. LED lights, well yea, those are on 14. I think all my lights pull about 5A total. ( all LED) Pull 12 if you want, but a waste if you pick your fixtures. Oh yea,. as you get older, you never have enough light so plan on double what you think and paint everything white before yo occupy. At least with LED you don;t have the starter inrush that makes you use multiple branches for the lights like fluorescents. I kind of like the idea of ceiling outlets so you can use whatever cheap HF "shop" fixtures are on sale this week. Another great use for quad outlets. Do pay attention to the total number of fixtures on a circuit. With LEDs, the current is so low we are tempted to exceed the 12 to 15 code for fixture count. I do not know the wisdom of this bit of code.

I think, if you run a neutral on your 220 lines, in one outlet you could have a 220 and split for 110's as it is one breaker. I wouldn't.

Most code does not allow two circuits in one box, so running two duplex outlets on different branches is usually a violation. You want the quad outlet not for current, just for how many things may be plugged in.

Look at your code for GFI. I prefer GFI breakers to outlets. I think within 3 feet of an exterior door, all kitchen and bath, or 3 feet from any water is code. Arc fault were originally required for bedrooms, not elsewhere. I see no harm in all 110 branches to be GFI other than cost.

I do agree completely with Klutz. If electrics are not your bead and butter, higher a pro. There are a lot of small details in the code that are there for a reason that is not always obvious to mere mortals. ( or unfortunately, quite a few licensed pros when it comes to shops.)

Quad boxes are great. The fewer power strips the better.

Pay attention to the outlet spec. Buy the $5 "commercial" grade, not the 98 cent contractor grade. Easier to wire, won't fatigue. With 10 gauge, you don't want to have to loop the ends, so the side flat clamp is a big plus. Never use the rear push in type.


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## Knockonit (Nov 5, 2017)

in my new 26×36 ft shop with 10ft ceiling, i put them every 4 ft on walls, with strategic 220v outlets in quite a few places. in the cieling i put outlets every 6 ft, but i intend to use retractable ext cords, as i picked a gaggle of them up from a remodel, all 12 ga, with triple outlets, also a few locations to drop a light. 
i used led 4 ft lights, that can be dimmed, a couple pals said ''holy jeebus;; oughta issue sun glasses, but in dark of nite, its awesome, did switch each bank separately so i could shut some down, put a mezzanine over office 8×20 for lumber storage, and did pick up a rolling platform ladder to access, there is open trusses, with foam at underside of roof, and i put led lights over mezzanine so i could see the lumber pic. all circuits are 20 amp, as i do metal also, had them put a couple 220v outlets on the 12×35 covered patio for me plasma cutter and big arse welder i sometimes use. 
and to make it all work, i put in two flitch beams about 4 ft apart on patio frame so i could hang an electric winch to get stuff outta me trailer and truck, getting older i find i'm far from able to unload a lot of items. 
only issue i screwed up is the height of mech room, should gone to 9 ft, but i'll finger something out
good luck, more is easier at the onset, after thoughts on electric can be a pill
rj in az


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## Unknowncraftsman (Jun 23, 2013)

I don't like too much over head light esp the new LED. It's fine for machinery areas table saw bandsaw and probably is safer.
Natural light in the mornings and evenings is the best. Low raking light while sitting at our bench has to mentioned this is when we have our best opportunity see our work. 
I know some of you already know this trick for finishing.
If your project looks good under the scrutiny of low raking natural light it's going to look great inside the house.
Good Luck


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## ibewjon (Oct 2, 2010)

For these old eyes, more and more light is better. If you don't like the 5000k bright white, there are less available that are 3000 or less, more yellow. I know low angle light is good for seeing defects, but a hand floodlight is good for that.


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## WhyMe (Feb 15, 2014)

*tvrgeek* - What code prohibits more than 12 to 15 lighting fixtures on one circuit, plus prohibits more than one circuit in a box? Not the NEC.


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## Unknowncraftsman (Jun 23, 2013)

> For these old eyes, more and more light is better. If you don t like the 5000k bright white, there are less available that are 3000 or less, more yellow. I know low angle light is good for seeing defects, but a hand floodlight is good for that.
> 
> - ibewjon


Don't knock until you try it. 
Even old eyes can benefit from natural light.
What's a hand flood light I'd like try one.


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## WoodZenStudent (Mar 25, 2021)

Wow! Lots of great information. I'm getting a few quotes. I hope they aren't as high as the $6,400 insulation quote, otherwise, I might need a different hobby


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## ibewjon (Oct 2, 2010)

Remember to check the price for conduit in place if romex. In my area, it is often less expensive than romex, and circuits can be added later.


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## david2011 (Apr 1, 2008)

For the 110V circuits my perspective is a little different. Unless you're running a server rack there are very few tools that need 20A at 110/120V. Most max out at 15A and 14 gauge wire is adequate for 15A. Since many local codes require 12 ga wire even on 15A outlets, you have plenty of reserve capacity with 15A outlets on 20A breakers with 12 ga wire.

The only place I've had a problem with a breaker popping regularly was with a metal lathe. The motor was only 1 hp but if it was set to run in its higher rpm range, up to 1400 rpm, the inertia of the heavy chuck trying to resist spinning up would cause the breaker to pop frequently. Imagine having a 30 pound blade on a table saw as a comparison.

If you think you might ever have an AC welder, you might want one 50A 240V circuit although many of the newer MIG machines only need 15A 110V. The other thing I would change is to add a 110V outlet on either side of the overhead door. I didn't put an outlet in an area like that in my shop and I wish I had. The nearest outlets from one corner are both past doors, 7-8 feet past a man door on one wall and 11-12 feet past an overhead door on the adjacent wall. Ironically, that's the corner where my breaker box and the 50A welder outlet are located.


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## ibewjon (Oct 2, 2010)

You probably don't need 20 amp receptacles, but you do need 12 awg wire. You can always upgrade the receptacle, but unless you use conduit, the wire is there to stay behind finished walls. And whatever number of receptacles you think you need, add more.


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## therealSteveN (Oct 29, 2016)

For my shop area I wired with 12, and used quad boxes set every 8' of wall. I ran 3 circuits leapfrogging them around as I went. so one box is from one circuit, and the ones on either side are also from another circuit. That way I can't over load a circuit at one 8' stretch. If you work by yourself you can't be in 2 8' stretches at once.

IF you have any tools that can run all by themselves… CNC or Laser. Make the electric for that a home run, so you don't stress that line if you are elsewhere running a 3 1/2HP router or something, or 2 somethings on an autostart vac, and a big hand held tool, or machine tool, and DC.

Beyond Fred's insight to use ceiling mounted outlets to hang your lights. I would add buy the dirt cheapest lights money can buy WITH a cord/plug attached. There was a time when spending big bux on an electric device was a sound theory, it's time has passed. Everything electric anymore is junk. To spend big bux on a light is silly money. Plus if it turns out the light you hung on Monday, just quits working on Friday, if it only cost 6 bux it doesn't hurt as bad as if it were 99. Shopping around you can find cheap or expensive in 5000 lumens, and just use those lovely BRIGHT white bulbs.


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## stevejack (Apr 5, 2020)

I watched a video about this and a guy had a good point. Said even if you ate running #14 with a 15 amp for say lighting use a 20 amp Duplex Outlet. They are way more meaty and safe


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## wapakfred (Jul 29, 2011)

> I watched a video about this and a guy had a good point. Said even if you ate running #14 with a 15 amp for say lighting use a 20 amp Duplex Outlet. They are way more meaty and safe
> 
> - stevejack


You might get in trouble putting a 20amp duplex on a #14 wire. That's a bad idea.


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## MadMark (Jun 3, 2014)

Putting an over amp outlet on skinny wire makes an electrical "promise" that the wiring can't deliver. This will cause nuisance trips.

Worst case is someone comes along and replaces the 15A breaker with a 20A because obviously the breaker is undersized for that nice 20A outlet.

Next thing you know the ins co won't pay because the Fire Marshall said improper homeowner wiring was the cause.


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## controlfreak (Jun 29, 2019)

Whether using a 15amp or 20amp duplex you can and should get the "commercial" duty if you want a beefy outlet. In a shop you may be unplugging tools a lot and the cheap ones will get "sprung" where the plug is not making good contact. This results in flakey operation and heat which is not a good thing. Compared to later replacement it is cheaper IMO to pay the extra and go commercial 20 amp all the way around.


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## ibewjon (Oct 2, 2010)

Buy the commercial or even better industrial receptacles. NEVER, NEVER put a 20 amp receptacle on a 14 awg wire circuit Make it easy, just use 12 awg for everything. The electrical system is the life of the shop. It is the last place to play Scrooge.


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## craftsman on the lake (Dec 27, 2008)

For a lot of larger power tools a 15amp will sometimes trip. Go 20 if you can. Also, if you run a wire, especially a #10 wire to it's own breaker, you can at some point put in a 220 breaker and 220 plug on it even if you wire it for 110 now. Sort of built in future proofing some of the plugs.


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## WoodZenStudent (Mar 25, 2021)

Well, estimates to wire this small shop are in the $10K range and it can be done in a day.


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## bigblockyeti (Sep 9, 2013)

> Putting an over amp outlet on skinny wire makes an electrical "promise" that the wiring can t deliver. This will cause nuisance trips.
> 
> Worst case is someone comes along and replaces the 15A breaker with a 20A because obviously the breaker is undersized for that nice 20A outlet.
> 
> ...


Not how it works.
You can get in trouble for too big of a breaker for the wire or receptacle but not too small.

To the OP, if kids will ever be in there, run power to all the dangerous stuff like saws, drills, sanders, routers, etc. from a separate sub-panel and kill the breaker from the main panel (in the shop) feeding it so you can have lighting, dust collection, compressed air, battery chargers and the like without having to worry about any of the sharp spinny bits.


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## ibewjon (Oct 2, 2010)

And all 120volt receptacles must be on ground fault protection. Code says "at or below grade, but a concrete slab sitting on grade is included even though the top of the slab is above grade. Do concrete is a great conductor. 10 k is a lot of $, but 12-2 romex is about 1$ per foot. Conduit is a better, safer job for about the same money, maybe even less.


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## rwe2156 (May 7, 2014)

Consider surface mount circuits for 240V. Allows for adapatability when placing machines.

I strongly recommend hiring an electrician if that's feasible for you. I had an electrician wire my shop, he ran one circuit for all my 240V machines, except one dedicated for 5Hp compressor. Daisy chained all the LED lights, divided into 2 circuits.

Also, any 120v machines such as table saw, should be on dedicated 20A circuit.

Another thing he did was run 2 hots in a circuit and split the outlets. This way, for example, you don't ever have to worry about your miter saw kicking the breaker if the shop vac is running.


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## WoodZenStudent (Mar 25, 2021)

Update: new wiring has been run and outlets added. We found out my existing panel is too small so that's the last part to add. It's starting to look more like a shop!


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## ibewjon (Oct 2, 2010)

Panels too small, circuits too few. Standard shop. More available power is always better. You may not need it today, but tomorrow?? Maybe.


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## ibewjon (Oct 2, 2010)

And remember, all 120 volts receptacles must be ground fault protected. The code states shop floor level at or below grade. A slab on grade with the surface above grade is included, as concrete is considered a grounded surface.


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## Woodmaster1 (Apr 26, 2011)

I put in a 200amp panel. My circuits were wire with #12 wire all 20amp circuits and #10 wire for my 30amp 220volt circuits, and #14 on my lighting circuits. I have 1 30amp 220v receptacle on each wall. Other circuits 40amp for the pool heater, 30 amp hot water heater. My panel is only 1/2 full.


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## ibewjon (Oct 2, 2010)

That is great. I hate seeing a new panel filled at the start with no room for changes and expansion.


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