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.
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.
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?
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?
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..
@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
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
@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.
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.
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.
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.
@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.
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)
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.
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
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.
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.
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.
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.
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.
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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