Shop wiring

  • Advertise with us

« back to Focus on the Workspace forum

Forum topic by Steve posted 06-26-2013 07:25 AM 1663 views 0 times favorited 21 replies Add to Favorites Watch
View Steve's profile


186 posts in 1962 days

06-26-2013 07:25 AM

Trying to get a few tips for wiring my shop. I have been thinking of running my 15 amp 14/2 circuits inside the wall and running my heavier circuits in EMT on the outside of the wall. Most of my larger tools are wired for 220, those tools being a table saw, jointer, thickness planer, 1 1/4 production shaper, 17” band saw, 6’ x 108’ sander, 24” double drum sander and a compressor. I am not to sure if I really need a separate circuit for each one, or if I should run maybe three circuits as most of those tools are mounted on wheels anyway and can be moved easily.

I was also thinking about having my receptacle box’s around 4 feet of the ground. Nothing worse than bending over all the time to plug things in, especially if you have a mess and need to move things around to plug stuff in.
I also have a drill press and scroll saw which are wired 110 and they should probably get their own 15 amp circuit, maybe increasing the wire size to 12/2.

Any way any suggestions would be greatly appreciated.

21 replies so far

View toolie's profile


2120 posts in 2590 days

#1 posted 06-26-2013 10:20 AM

more outlets are always better than less. minimum two 220v 20a circuits, lights on at least one, preferably two, 15a circuits and at least two 20a general purpose circuits.

-- there's a solution to every just have to be willing to find it.

View EEngineer's profile


1098 posts in 3575 days

#2 posted 06-26-2013 11:17 AM

I’d recommend the sockets be a little higher than 4’. That way you can lean a 4X8 sheet against the wall and still reach the socket.

The only 15A 110V circuits in my shop are for lights. Everything else is 20A. Run 12 AWG everywhere – upgrades are easy and it keeps the resistance down for very little difference in cost.

NEC requires GFI on every circuit. I found GFI sockets to be cheaper (way cheaper!) than GFI breakers on 110.

If you have a detached shop pay particular attention to the NEC rules for grounding.

-- "Find out what you cannot do and then go do it!"

View HorizontalMike's profile


7749 posts in 2876 days

#3 posted 06-26-2013 12:33 PM

IMO, if you are in fact installing new wiring inside the wall, forget about using 14/2 wiring(way too small). Go with 12/2 as a minimum. You usually only get one chance when initially wiring inside the wall, so make the most of it and you will not regret it in the future.

Also, 4ft is a good height for receptacles 8-) Suggest 4-gang boxes every 5ft (or at least 6-8ft) apart. I originally wired my metal building/shop only at the major pillars about 15ft apart, and had to retrofit several more receptacles at half that spacing when I discovered just how much I needed them. You really do need closely spaced receptacles.

If you CAN run separate 240v circuits for EACH machine, so much the better. It sure makes identifying them easier at the power panel. I used a 125amp power box, but now wished I had gone with another 200amp panel like at the house main feed. You cannot go wrong with more room at the power panel. Bigger boxes do not cost that much more and the return on convenience is priceless, IMO.

-- HorizontalMike -- "Woodpeckers understand..."

View pmayer's profile


1026 posts in 3027 days

#4 posted 06-26-2013 01:03 PM

I would run everything inside the wall. Separate circuits for each 220 tool. All 12 ga. wiring for your 110 outlets, 14 ga. for lights. I would also suggest running a dedicated 110 outlet on each wall that can be converted to 220 by just swapping a breaker if you ever want to. This is handy and I have taken advantage of this in my shop. I ran 110 outlets on every third stud which has worked out well. I put a separate circuit on each wall which is overkill for sure, but I do sometimes share my shop with my father so it is conceivable that we would overload a circuit but not very likely since all of my stationary tools are on dedicated 220 circuits. Its also nice to have an outlet in the ceiling over my assembly table, where I have a retractable extension cord. I use that thing all the time.

-- PaulMayer,

View REO's profile


928 posts in 2036 days

#5 posted 06-26-2013 01:53 PM

As EE suggests go a little higher than 48” for the random sheet of material leaned against the wall. if you are working alone typically there is certainly no need to run individual circuits for each machine. In my shop I ran individuals for air compressor, DC and a welder outlet. the rest are split between two 220 20A circuits and the 110V is piggybacked on those so there are only two runs of wire for general outlets. I run a 7.5 HP RPC which is also wired in the walls permanently but unplugs so I can take it with me if needed elsewhere. Many of y tools are in rolling nests. TS, Router table, Planer, 6×48 sander on a lift. DP, Shaper, BS. I bring 220 to the “nest” on 10/4 from the wall and have 110v outlets mounted all round for power tool use at the “nest” For the 220v I used 12/3 WG, the 3 PH is run with 10/4, and the welder with 6/4. All 110 outlets are required to be tamper resistant as well. in my situation I couldn’t “daisy chain” the GFI’s either

View BBF's profile


143 posts in 1801 days

#6 posted 06-26-2013 02:32 PM

Take HorizontalMike’s advise when you think that you have enough outlets then it is time to double them. Extension cords are not the way to run a shop. 14-2 should be used only for lights and not on a circuit with any tool on it, you don’t want the lights going out when you are in the middle of cutting something.

-- I've never been disappointed buying quality but I have been disappointed buying good enough.

View macatlin1's profile


78 posts in 2905 days

#7 posted 06-26-2013 03:53 PM

For my shop I put 220VAC outlets on the East and West walls located 12 inches above the floor. Each wall was on a separate circuit. For the 110VAC outlets I put separate circuits for the East, West and North walls. On the East and West walls the outlets were mounted at 54 inches to avoid having to bend down and get behind the equipment and to allow leaning 48 inch wide stock to lean against the wall without interfering with the outlets. On the East wall I also installed a separate single dedicated outlet (switched) for the dust collector. By going with a dedicated outlet there is no need for GFI. The switch allows me to turn on the DC without having to reach around behind it. I did buy a 20A switch. The DC circuit also powers the light over the man door on the outside. The outlets along the North wall are at conventional height as having equipment or storage along this wall will interfere with access to the house. All 110VAC strings are started with a GFI outlet. I also have an “office” alcove with it’s own GFI protected circuit which was part of the original house/carport/garage/shop circuit. The lighting in the shop is 20A with 2 strings of 6 dual tube 4’ fluorescent light fixtures and 6 can lights where the fluorescent fixtures would interfere with the garage doors. Each string is controlled by a separate switch. I retained the original garage light and turn it on if I am working at night just in case the lighting circuit fails. I wouldn’t want to be left in the dark with running machines. I also added a separate airconditioner circuit with a dedicated outlet. The AC and outlet are mounted through the wall and near the ceiling. I also replaced the duplex outlets the garage door openers were plugged into with single outlets so they became dedicated and not requiring GFI’s. I had no problem with the inspector and even though I did the work myself he was impressed.

View Grandpa's profile


3259 posts in 2637 days

#8 posted 06-26-2013 05:33 PM

I put 220V where needed and sized as needed. I used 110V 20A for everything else. Also look for 20A receptacles. Most are 15A. make everything heavier than required today. I place my receptacles at 5 ft because U have a metal building and there is a horizontal member there. Got luck I guess. GFCI everything on 110VI have receptacles every 5 ft horizontally too. All around then some in the floor.

View teejk's profile


1215 posts in 2646 days

#9 posted 06-26-2013 06:25 PM

If you are going to hide the wiring behind walls, figure out your interior finishing material so cutting in the outlet boxes hits an edge. Faster than trying to cut boxes into the middle of a large panel. I personally like the looks of EMT external conduit and since I am always hanging stuff I always know where the wires are. They are a bit of a dust collector though.

View SeattleD's profile


15 posts in 1761 days

#10 posted 06-26-2013 06:47 PM

I’m facing a similar challenge, compounded by being a “renter”. My place, built in 2007, has a ~540 sq’ garage, with ONE 15 amp 120 volt outlet, fed by 14 ga. A major limitation. It’s hard for me to believe this is even up to code, but given the relative newness of the place, it probably is. And since I am renting, I’m limited in what I can do to address the situation.

-- David

View Knothead62's profile


2584 posts in 2923 days

#11 posted 06-26-2013 07:02 PM

If I recall my training at Lowe’s to work in the electrical department, you are only required to have the first outlet on the line as a GFCI. The rest “downstream” can be regular outlets and the GFCI will trip when needed. Has this changed? Would like clarification. Thanks.

View Kent's profile


155 posts in 1758 days

#12 posted 06-26-2013 07:20 PM

I strongly agree with the boxes mounted a little over 4’, and with mounting as many as you can. Because workshops can, and should, be dynamic spaces that adapt as we do, I recommend that all wiring be surface mounted so that changes are considerably easier.

In a past shop, I had a master shut-off switch at the door and 2 sub-panels. The one was a small panel and the only circuit on it was for the lights and the air filter. The second sub-panel had it’s own shut-off switch and everything else. I plugged an old radio into one of the 115V circuits on the second panel, mounted the radio where I couldn’t reach it, and then turned it on to a local radio station. Then, whenever I heard the radio, I knew that my tools were live and extra caution was taken. If I wanted to change a blade or make any other potentially dangerous changes, I would shut off the master switch on the second panel. Hearing the radio was also a cue to me to turn off the tools master shut-off when I closed up the shop. As a bonus, it would be impossible to trip a breaker with a tool and be stuck in the dark with a spinning blade. It worked well for me and it will also be done in my new shop (summer 2014)

-- If I knew then what I know now, I'd have made a completely different set of mistakes.

View smitdog's profile (online now)


339 posts in 2067 days

#13 posted 06-26-2013 08:04 PM

Knothead, that’s what I had learned and the instructions that came in the box of GFIs I got confirmed – you only need a GFI outlet at the beginning of a circuit to protect the whole line, but only if wired correctly! A single line must feed the GFI’s input terminals and then the wiring must come out of the exit terminals so that the GFI breaks the line. If you try to pigtail the outlet or branch off at a junction box before the outlet you will bypass the GFI’s ability to break the connection. So everything in front of the GFI is not protected but everything coming out of the GFI box IS. I GFI protected my whole kitchen (10 outlets or so, can’t remember) on 2 separate 20A breakers and only used 2 GFI outlets.

I tested each outlet in the string and they all worked just fine.

-- Jarrett - Mount Vernon, Ohio

View jimmyb's profile


185 posts in 1854 days

#14 posted 06-26-2013 08:09 PM

As an ex IBEW electrician, my two cents. You do NOT need a seperate circuit for every 220v machine unless you plan on running them all at the same time.

Knothead62 is correct with GFCI outlet. First outlet then control the next 5(?) outlets wired after it.

I long the taller than 48” height for reasons stated . Switches are mounted at 52” to top of box and would then be a good height for all.

-- Jim, Tinley Park, IL

View Shawn Masterson's profile

Shawn Masterson

1325 posts in 1910 days

#15 posted 06-26-2013 10:50 PM

I agree with sharing 220 circuits. the only advice I have for sharing is to plan out the locations and size of the machines.
My shop has 3 – 220 circuits
1 – 30 amps – TS 3Hp and not in use right now but was for the old planer 5 Hp
2 – 30 amps – compressor 5 HP and DC 3Hp
3 – 50 amps – RPC 10 Hp (for the new planer) and welder
as for 110 each wall has a 20 amp circuit for recepts and a dedicated circuit for lights.

showing 1 through 15 of 21 replies

Have your say...

You must be signed in to reply.

DISCLAIMER: Any posts on LJ are posted by individuals acting in their own right and do not necessarily reflect the views of LJ. LJ will not be held liable for the actions of any user.

Latest Projects | Latest Blog Entries | Latest Forum Topics