Wiring your Shop

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Forum topic by Sac posted 09-28-2008 06:40 PM 5589 views 1 time favorited 12 replies Add to Favorites Watch
View Sac's profile


268 posts in 3632 days

09-28-2008 06:40 PM

I know this isn’t a subject about our tools and the how to use them type of question but I wasn’t sure where to ask this. I am gathering materials to build my shop. I’ll start it next spring. I currently have my breaker box, recepticles, wire nuts and so on. The box is a square d 235/200 amp box with a 200 main in it. I was wanting to know what type of wiring would be the safest to use. I plan on having 2 – 240 and the rest 110v. I have been looking at 6/2 ELECTRICAL ROMEX COPPER WIRE W/GROUND, 12/3 ROMEX W/GND COPPER INDOOR ELECTRICAL WIRE , and some 10/3 Romex wire w/ground. I just want to make it safe as possible.

Thanks in advance.

-- Jerry

12 replies so far

View lew's profile


12060 posts in 3753 days

#1 posted 09-28-2008 07:23 PM


Probably you will want to check out your equipment requirements first. Circuits using 20amps will need a minimum of 12 gauge wire and those using 15amps will need a minimum of 14 gauge wire.

Lighting will probably be OK at 14 gauge. The 10/3 will work for 240 volt applications up to about 5hp motors.

All this is for single phase.


-- Lew- Time traveler. Purveyor of the Universe's finest custom rolling pins.

View Patrick Jaromin's profile

Patrick Jaromin

405 posts in 3831 days

#2 posted 09-28-2008 07:41 PM

In my neck-o-the-woods, all electrical circuits must be run in conduit…Romex is foribidden by local codes. Since you’re considering using Romex, I’m guessing that’s not the case in your area, however I would seriously consider using it anyway. It’s tons easier to, say upgrade a 15A circuit to 20A simply by pulling 12ga. wire to replace the existing 14ga…not such a simple feat with Romex. Additionally, you can run conduit on the interior wall and place boxes in convenient spots to more readily “branch off” to add new circuits or outlets for existing circuits in new locations.

Additionally, the metal conduit acts as the ground and it’s therefore much more difficult to improperly ground a circuit.

Just my 2 cents.

-- Patrick, Chicago, IL

View Randolph Torres's profile

Randolph Torres

295 posts in 3527 days

#3 posted 09-28-2008 07:50 PM

Sac: Patrics advice is very sound always go with the larger guage in shop applications you never know when your going to upgrade to larger equipment, or if you have a buddy over and just happen to start 2 tools at once—think of your futures (future installs) and save time and money in the long run. Don’t feel shy about asking about any aspect of woodworking its all a piece of the same pie.

-- another tip from cooperedpatterns

View hisparadox's profile


16 posts in 3736 days

#4 posted 09-28-2008 08:00 PM

get yourself a copy of the code rules for you particular area, along with a basic wiring book, and refer back to there.

where Im from, as a home owner, I am allowed to do my own wiring to code, as long as it is inspected by an electrical underwriter, in my own shop, I have a 100 amp panel, I ran #2 wire from a 100 amp breaker in the house panel to a sub panel in the shop 160 feet from the house, I also ran a spare number 2 wire just in case one failed, this is all housed in 2 inch conduit.

for lighting, I ran 14 gauge in conduit on the ceiling to florsecent fixtures, I had originally used home depot bought 85 watt compact floursecent fixtures, but replaced them with regular 4 foot shop lights, the fixtures home depot sells for the 85 watt cfls are garbage, and came within hours of burning the garage down, closer inspection revealed no heat shields, last time I buy any product sold by lights of america.

for basic 120 power, I ran 12gauge wire and 20 amp circuts, and did the same for basic 220 circuts
for more specific uses, I go right back to the panel and run as required for the planer, a vacuum molder and some other high current demands.

your main service into the shop is what you want to be the most generous with, voltage drop can be a killer on equipment, in fact it doesnt hurt to have a voltage gauge in full view to monitor your voltage, no point in running a machine to its death when the input voltage is only 99 volts

I try not to run any machine on less than 120 volts of power

View DeputyDawg's profile


196 posts in 3963 days

#5 posted 09-28-2008 08:22 PM

I just wired my shop here in Missouri and where I live there is NO CODES. Boo on them. Anyway I ran all of my electric with the 12GA wire in conduit. I also ran recepticals completely around the shop using 2 circuits for each one and wired every other plug on each of the two circuits. Also my advise on lighting is use the 0 degree ligjhting. That way youi won’t have any flickering. I got mine at Lowe’s and they were $67. per light plus the 8’ bulbs. And I ran each run of lights on it’s own circuit. I have had no problem since I wired it that way. Also when you turn on each run of lights the first time LEAVE THEM ON for at least 24 hours. That was advise I got from an electrician. Don’t forget to post pictures of your progress.

-- DeputyDawg

View tenontim's profile


2131 posts in 3743 days

#6 posted 09-28-2008 09:31 PM

I built my shop about 3 years ago, and I don’t use 14 gauge at all. I used 12 for all of the 110 volt circuits and 10 gauge for the 220v circuits. I have a lot of wire and a lot of circuit breakers. Nothing that pulls many amps is on a circuit with another. If there are, they are not two pieces of equipment that I would be using at the same time. My 110v outlets are about 3-4’ apart, with a couple in the ceiling. I also have 12, four foot lights on two separate circuits by themselves.

View rtb's profile


1101 posts in 3711 days

#7 posted 09-29-2008 05:50 AM

Don’t forget GFI on every circut. they will kill the power to a short while your circut breakers are thinking about it. I agree about conduit/ My overheads are 3 52in fans 4 23 whatt curly cue bulbs ( same lumens as 100 w. ) fans and lights are wired to seperate switches. Of course I still need local lights when working late but I don’t think there is and type of shop lighting that dosen’t. rt

-- RTB. stray animals are just looking for love

View Sac's profile


268 posts in 3632 days

#8 posted 09-29-2008 10:15 AM

You all rock! Thanks for sharing your knowledge and wealth of information here. I had bought a couple of wiring books a few months ago I had forgotten about. This barn project has me so busy I just forgot about the books. I have a list iof different wire from Amazon that I will compare some local prices too. This barn has 2-250ft rolls of 12/3 in the work room I will use. so now I am pricing out some 10/3. What is wierd is that I have not seen any wire yet that says 30 amp. Well anyway again thank you all so much for sharing your wealth of information here.

-- Jerry

View snowdog's profile


1164 posts in 3981 days

#9 posted 09-29-2008 02:33 PM

I am with Tenontim, I never run 14g wire if I have an option, mainly because you never know when you want to change or add something and having the 12g seems to give me more options in the future.

-- "so much to learn and so little time"..

View Kindlingmaker's profile


2656 posts in 3525 days

#10 posted 09-29-2008 06:11 PM

I have had good fortune with the idea that if a 14g wire works then 12 g wire is better and so on…

-- Never board, always knotty, lots of growth rings

View hairy's profile


2703 posts in 3530 days

#11 posted 09-30-2008 12:58 AM

If you are running a circuit that will be outlets, use a GFI for the first outlet in line from the breaker box. All other outlets on this circuit will be protected by the GFI.

-- My reality check bounced...

View sIKE's profile


1271 posts in 3752 days

#12 posted 09-30-2008 02:28 AM

However you wire armored/romex make sure you run 12/2 or 12/3 for your 110V applications and 10/2 for your 220V applications, but you will need to make sure the distance of the run does not exceed to capacity of the wire. If you separate your lighting runs from your outlets just run 14/2 or 14/3 for them. This is what did. Remember your 12/3 or 14/3 (110V applications) means that you will have two hot wires, plan your breaker box capacity properly.

If you read through other electrical forum questions you will see that I am a big fan of the “Wiring Simplified” book.

Hope this helps, if you have any other questions feel free to PM me. I wired my own shop from soup to nuts and learned a lot in the process..

-- //FC - Round Rock, TX - "Experience is what you get just after you need it"

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