# Electrical Wiring in the shop



## jgreiner (Oct 23, 2010)

I got the subpanel added to the basement, but I was fairly confident in my ability to actually do the wiring myself. I went to homedepot to get the materials I needed, breakers, boxes conduit etc..

The person there, said that I needed 12/3 wire instead of 12/2 because I'm wiring into a subpanel. I hadn't heard that, but alas that's what I got. Now I've done some research and now I feel I've gotten the wrong wire and I should have gotten a 12/2 instead.

As a note, I plan to use the wire for a 20amp 220v outlet (and a separate 110v chain of outlets).

Am I hosed? I already cut the wire so I don't know if they'll take it back, if I am supposed to use the 12/3 wire I'm not sure what I'm supposed to do with the extra red wire. The youtube video's I watched to prep for this where using 12/2 wires.

-jeremy


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## Redoak49 (Dec 15, 2012)

I am certain that there are a number of threads on this. 12/3 is correct with two hots(back and red) a neutral and separate ground in the sub panel.


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## crank49 (Apr 7, 2010)

If you are connecting a 220 volt outlet the black and the red wires are the hot leads.

The spare wire might either be white or green, you didn't say, but which ever color it has to be the ground.

The reason they said you need 12-3 instead of 12-2 is because in a subpanel the ground and neutral (in the case of a 120 volt outlet) have to be isolated from each other and the neutral buss and ground buss are also isolated in a sub-panel. the 12-2 w/gnd wire has a bare wire for the ground. You can't use that bare wire for the neutral.

There is supposed to be only one place in a system where the neutral and the ground are bonded (tied together) and that is in the main breaker panel.


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## hjt (Oct 22, 2009)

Sounds like Crank has done some of this in the pass. Check out youtube as well for info.


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## jgreiner (Oct 23, 2010)

Thanks Crank,
That all makes sense looking at the breaker box and from what I've read about the separate ground and neutral bars in the subpanel (and what I see in my subpanel). I guess my confusion came in at the outlet. Since it only had 3 screw connectors (1 hot brass, 1 neutral silver, 1 ground green), do I have to get a special type of outlet? Do I cap one of the hots? or do I put both hots into the hot screw?


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## Holbs (Nov 4, 2012)

jeremy… what is the use of the 20amp 220v outlet? what machinery will you be running and what is the required amperage? i went the safe route and used 10/2 red/black/bare ground wire for all of my 220v outlets. 
might want to research 220v outlets and wiring. putting both hots into a single screw = trouble. i researched a good 2 months of cazillions of youtube videos, electrical webpages, electrical remodel, and municipal code BEFORE i even began my electrical remodel of my garage (take a peek at my blog of the matter if it helps).

OH WAIT! did you use 12/2 for the subpanel feed? or just for 220v outlets?


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## crank49 (Apr 7, 2010)

Two hot leads, the black and red, make a 230 volt outlet's power feed and the green screw is the ground.
If you are speaking of a 120 volt outlet, you use a black and a white wire plus a ground.

Back in the breaker box, the black and red wires are connected to the two hot lugs on the 230 volt breaker..
for the 120 volt circuit in the breaker panel the black wire goes to the single hot lug on the 120 volt breaker, the white goes to the neutral buss and the ground wire goes to the ground buss. This assumes you are still talking sub-panel.

#12 AWG wire is good for 20 amps. That's usually plenty for 230 volt machines. up to about 5 hp induction motors and is just adequate for a 4500 watt 240 volt heater. I'd really feel better with a #10 AWG, 30 amp capacity wire for a 4500 watt 240 volt heater because in low voltage conditions, like under 220 volts, it's really slightly over loaded by about 1/2 to 3/4 of an amp on #12 wire..


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## jgreiner (Oct 23, 2010)

@holbs
I have an electrician install the subpanel itself, and 10 awg is good for 30amp, but my jointer requires 15, I put it on a 20amp to be safe, which 12awg is what I read was rated for 20amp.

@Crank
Yes everything is going into a subpanel, so am I correct that both black and red go to the same screw, and the white goes to the neutral and the bare ground goes to the ground screw. (I think that's what you were saying I just wanted to make sure)

For the 110v I should get 12/2 wire then, and that pretty clears up my confusion 

-jeremy


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## Holbs (Nov 4, 2012)

you used 12/3 for a 220v wood working machine. you have a spare wire that you do not need (the white?). i ran 10/3 for 4 of my 5 220v outlets only because i got a great deal on the 10/3. red goes to one terminal, black goes to another terminal, the bare ground goes to ground screw, the white is un-used.

12/3 or 10/3 is used when you need 220v AND 110v (think of a 220v oven with a 110v clock).
12/2 or 102 is used if purely needing 220v.

doesnt hurt you ran 12/3… you just will not be using one of the wires.
i could be getting the white and bare mixed up… it's been awhile


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## jgreiner (Oct 23, 2010)

@Holbs
It's my understanding the white is needed to connect to the neutral bar in the subpanel, it seems silly if it doesn't actually get connected to anything on the outlet end.


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## Holbs (Nov 4, 2012)

http://waterheatertimer.org/images/Inside-Main-Breaker-Box-12.jpg

look at the 10-2 image in the middle. red&black are the 2 hots (both go back to the breaker), the bare wire goes to the ground bar.
this image is of the main breaker panel. a sub-panel is the same for wiring EXCEPT there is no electrical bond piece between the neutral bar and ground bar.


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## crank49 (Apr 7, 2010)

*NO. Black and Red DO NOT go to the same screw.*

A 230 volt circuit has to be attached to a 230 volt breaker. 
The 230 volt breaker has two screw lugs where you attach wires.
One wire will be black and goes to one of those screws.
The other wire will be red and goes to the other screw on the breaker.
If your breaker only has one screw it is a 120 volt breaker and can not supply a 230 volt machine.


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## jgreiner (Oct 23, 2010)

Hi Crank,
Yes I understand that on the breaker, the 2 hots get screwed in seperatly, it has 2 screws that's not the issue. I'm referring to at the outlet.


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## Grandpa (Jan 28, 2011)

modern 220V receptacles have 4 wires and 4 pins on the plugs and 4 places in the receptacle.


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## jgreiner (Oct 23, 2010)

@Grandpa
My jointer is 3 wire, which I attached to a 3 prong twist lock plug.

I'm trying to wire the 3 prong twist lock outlet and I misspoke is has the 2 brass screws for the 2 hots (on opposite sides) and 1 for the ground. I'm just unsure what to do with the neutral.

My problem may be I have the wrong outlet and I need a 4 prong outlet, and I have to figure out if I can get a 4 prong plug for my 3 wire jointer.


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## 111 (Sep 2, 2013)

Just don't use the last wire.


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## jgreiner (Oct 23, 2010)

The last (white) wire gets screwed into the neutral bar on the subpanel, is that really it I'm not supposed to cap it?


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## 111 (Sep 2, 2013)

As far as I know don't use it at all, cap both ends, but i could be wrong, I'm not sure.
I did see this for using your 12/3 to use additional outlets. (not that you are but you could)


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## UpstateNYdude (Dec 20, 2012)

I'm confused why exactly are you using 12/3 AWG? 12/2 AWG is all I've ever used running all my 220v lines why waste the extra money on 12/3 when it's not needed, but like Holbs said just connect the red and black to the hots and the ground to the ground and you're done the white can just be capped off.


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## Holbs (Nov 4, 2012)

jeremy.. 220v receptacles come in various configurations. i just bought the standard HD configuration (identical to the receptacle keven shows in his picture above) and also bought the matching plug. i believe twist locks have a circular blade input instead of horizontal & vertical. i'm sure you can find matching receptacle (3 prong twist plug for a 3 prong twist lock receptacle).
hmm… twist lock. i didnt think about doing that when i did mine. i'm going to make a strain relief tie-down near the 220v receptacles to not put so much pull-down from the cable itself. why go twist lock in the first place?

and yes… cap off the white inside the receptacle box and the sub-panel. but label it in the sub panel with something so you know what that odd ball capped white wire is doing in your panel 10years from now


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## jgreiner (Oct 23, 2010)

I was told 12/3 is required because I have to connect the ground and neutral to their respective bars in the subpanel, because in a subpanel they are not connected.


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## Holbs (Nov 4, 2012)

you were told wrong IF you are only using 220v for a 220v machine (jointer, planer, dust collector, etc).
you were told right IF your machine using both 220v for the motor and 110v for accessory (digital clock, for example).

seeing that this project is just for your jointer… 12/2 (or even 10/2) would of sufficed.

and dont worry. it took a LONG time for me to understand all the different gauges and nomenclature. when i started, i had no idea what 14/2 even was  closest thing to electrical interaction i've had previously was sticking my finger in a light socket when i was 8. same for the different between a planer and jointer. took awhile to sink in.


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## UpstateNYdude (Dec 20, 2012)

Like Holbs said if it's just to run the machine 12/2 is all you needed 10/2 is overkill and can be a bigger pain in the ass getting in the outlets but will work too…did someone at Lowes or HD tell you you needed 12/3 because half the people in the BB stores have no clue what the hell they're talking about and those are the ones usually in plumbing and electrical.


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## darthford (Feb 17, 2013)

FYI a couple examples of machines that come already corded for a 20 amp 240 volt straight pin receptacle, my new Grizzly 19" bandsaw and Grizzly 8" jointer. I think Canada is making them put plugs on their machines now, I would have preferred to install a twist lock plug but since both machines already have the straight pin plugs I decided to just install the matching receptacle as shown in the pic earlier in this thread.

That said it sounds like she needs 12/3 for the 110 receptacles and 12/2 for the 20 amp 240 volt so just don't use the white wire. She could tape it off in the receptacle box, I'm not sure what would be code in the panel for that wire.


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## icsparks (Sep 17, 2013)

You never said if your jointer is 120v or 220v. Just that it has 3 wires. Both types of circuits require 3 wires.
Make sure you know what it is that you need before wiring it up.

here is a link to the NEMA ratings and configurations that may help you figure out what you have or need.
http://frentzandsons.com/Hardware%20References/plugandreceptacleconfiguratio.htm

120 requires 1 hot, 1 neutral, 1 ground and one single pole breaker.
220 requires 2 hots and 1 ground and a two pole breaker.


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## GrandpaLen (Mar 6, 2012)

Jeremy,

You said *"As a note, I plan to use the wire for a 20amp 220v outlet (and a separate 110v chain of outlets)."*

If you meant you will be continuing the 12/3 beyond the 220v receptical to power your 110v chain of outlets, you will indeed need to terminate the white at the sub panel. (all 4 wires will be terminated at the sub panel).

As shown in crank49's post #11 you will terminate the black to one screw on the dual post breaker and the red to the other screw on the dual post breaker.
The white terminates to the neutral bar and the green or bare wire terminates to the ground bar.

When you get to the 220v outlet you will cut the black and add a pigtailed black wire and terminate the black pigtail to one hot screw.

The red wire will be cut and the end from the sub panel will terminate to the other hot screw. At this time you will cap off the red wire to the direction of your chain of 110v outlets.

The green (or bare) will be cut and you will add a pigtail to it and terminate the pigtail to the ground screw.

You will not terminate the white wire to the 220v outlet.

DO NOT cut or cap the white wire as it will be used in your 110v outlets.

Your 12/3 cable will have the red wire capped in the direction of the 110v outlet.

The black wire is pigtailed where you terminated it to the 220v outlet and the hot or power will continue on to your 110v outlets.

The green (or bare) wire is pigtailed where you terminated it to the 220v outlet and will continue on to your 110v outlet where you will use it as your ground.

The white wire was not cut at the 220v outlet and will continue on to your 110v outlets and be used as your neutral.

At this point the red wire is dead and you will use the black, white and green (or bare) wires as you would in any other cable, to wire a standard 110v outlet.

And this is why you will need to have the white terminated at the sub panel.

You are now, most likely suffering from information overload. I used the above method to do the same thing you had mentioned and it has been in service for 5 years in my shop with nno problems.

I must add that you will not be able to use your down stream 110v outlets for a 15 amp. - 20 amp. service at the same time as your 220v service is in use, but it should be fine for lights, radio. or lower amp draw equipment during the use of the 220v service.

There is a GOOD REASON to hire or at least consult with a local electrician and I believe you now understand why.

Best Regards. - Grandpa Len.

Work Safely and have Fun.

*EDIT;* By the way, your Home Depot customer service person was correct, if in fact you planned to run 1 cable to service the 220v and 110v outlets.

*EDIT #2;* Your 1st 110v outlet has to be a GFCI outlet, by Code.


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## CampD (Nov 8, 2008)

Rut ro, I smell smoke!


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## jgreiner (Oct 23, 2010)

Ok,
I understand my overall confusion now thanks for all the help and feedback. The 110v is going to be a separate breaker.

Things I learned 
220v doesn't require a neutral like a 110v does.
220v can be split into a 110v using a 12/3 wire didn't know you could do that, it's pretty cool but I don't think I'm going to do that. I may not have added a subpanel if I had known I could have done this because I could have added the breakers to the main box and done the combo 220v/110v for my main power tools which would only ever be run 1 at a time.

I do have the wrong wire, the 12/3 wire would have been needed if I was going to do the split 220v to 110v but since I'm not a 12/2 is good.

By trying to use the 12/3 wire I got myself worked up into a pile of confusion  since I didn't know what to do with that extra wire.

And yes, my first 110v outlet will be GFCI, I knew that much.

So I need to switch up my wire to 12/2 and things will get a lot simpler.

-jeremy


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## GrandpaLen (Mar 6, 2012)

Jeremy,

I believe you do have a handle on it. ;-)

...well with your new dedicated subpanel you will have plenty of room to grow, as you upgrade to additional 220v machines. Many of the larger machines are 110v/220v capable just by rewiring the motors from 110v to 220v and switching out the cord and plug, refer to your Operator's Manual.

Best Regards. - Grandpa Len.

Work Safely and have Fun.


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## Holt (Mar 15, 2011)

Since you are doing the wiring yourself and already have the 12/3 wire, you can wire your 120 volt outlets as a duplex circuit. Basically the top and bottom outlets are on different legs. Comes in handy when you want to plug in a vacuum and power tool into the same outlet and not worry about kicking the breaker. On the outlet, break the bar on the hot side and attach one hot wire to each side, hook up common and ground as usual.

Wiring your 240 volt circuits with 12/3 (or 10/3) works out well too. That four wire layout means you can tap off 120 volts for built in fans or work lights.


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## jgreiner (Oct 23, 2010)

I took the 12/3 wire back, was able to get the 12/2 wire that I wanted. Was able to get it all run and plugged into the 220v breaker, the outlet and was able to power up my jointer for the first time in 10 months or so.

Thanks for all the help everyone  later this week I'll run the wire for the 110v breaker for my tablesaw.

-jeremy


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## UpstateNYdude (Dec 20, 2012)

Congrats…what kind of jointer do you have?


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## jgreiner (Oct 23, 2010)

I have a Hammer A3-31 jointer/planer combo machine, I would highly recommend the machine it has served me very well.

-jeremy


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## MarkSr (Oct 14, 2012)

Jeremy, how old is that 20 amp 240v circuit drawing?

Anyway, on a 240 v receptacle you will have a black and red (hot) leads, they go to your two brass screws, the white (neutral) goes to the silver screw and the green or bare wire will go to the green grounding screw.

Do not put two hot leads under one screw, ever, if you ever see this, it is a mistake.

Do not use a white wire for your hot lead, if your not going to use all the wires place a wire nut on either the red or black wire. Always keep your white lead for your neutral, NEVER use your white for a hot lead, (unless it is properly marked at both ends) if you get mixed up back at the panel you could accidentally connect a hot white wire to your neutral bar, then you will have a dead short.

Code now is ALL outlets must be 20 amps for residential use, no more 15 amp outlets.

FYI, very simple explanation, without getting very tech., the difference between a ground wire and a neutral wire. a neutral could pick up current in rare occasions, a ground wire will not carry current.

You said you had an electrician install your sub-feed panel, if you watched him, you would have noticed that he bonded the grounding bar to the panel, but he didn't have to do that to the neutral bar.

Also I did not see anything above where your GFI Outlets, especially if your in a garage, but should be in every woodworking shop. IMO

Hope this helped, it's great your doing your own electric, just double check everything twice before you throw those breakers


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## MrRon (Jul 9, 2009)

To add a little confusion, I use 14-2 + ground for dedicated lighting circuits. 12-2 + ground for receptacles and for 220 volts (3 HP maximum). If I were using a 5 HP motor, I would have gone with 10-2 + ground. What size is the main breaker in your sub panel? In my shop, I have 200 amp service just for the shop. When I start my 220 saw and my DC, and my son is welding with his 200 amp mig welder, I get no momentary dimming of lighting. That's when you know you have sized your electrical distribution system correctly.


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## Grandpa (Jan 28, 2011)

To add more confusion to this thread, if you do use the 12-3 for 110V receptacles you must have it attached to a 220V breaker with the handles bonded. This allows both legs of the breaker to be used for different 110V circuits. I have a copy of the code in front of me with a photo if you have a FAX machine. If you will go to a store and look at new appliances you will find they now have 4 wires and the plugs have 4 pins on them. I assumed tools would be following suit and really don't know about new tools. I haven't bought any new tools in some time. Maybe I need to go look at them too. Check clothes dryers for instance.


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