[pburgh19]

I'm having a dilly of a time trying to sort this one out in my head -- the idea is to have two half-hot receptacles, spaced about 15' apart, controlled by two 3-way switches located opposite ends of the room. I'm comfortable wiring a pair of half-hot receptacles with a single-pole switch, but I can't seem to understand how to apply that approach when using two 3-way switches.

Not much of the circuit exists yet... only a 2-wire cable coming in to my first switch box (fed by another receptacle). No drywall yet, so I have room to run whatever I need.

Does anyone have a diagram showing how do this?

Thanks in advance! I'll keep reading/trying to figure this out in the meantime.

 

[joed]

Run a three wire cable from one switch to the other switch.

Then it is simple once you get three wire cable (14/3 or 12/3) to the new switch.
I am going to skip ground wires in the description. Connect all of them together and to the switch if it has a ground screw.

Take the two wires that would go the single switch. The wires could be both black or black and white. Might even be black and red. It doesn't matter.
Connect one of the wires to the common screw of your three way switch#1.
Connect the other wire to the black wire to your new switch#2 cable.
Connect the red and white wires to the remaining two traveller screws of the first switch#1.

At switch#2 connect the black to the common screw.
Connect the red and white wires to the remaining two traveller screws of the new switch#2.
If you tell me where the power comes in I can probably put up a drawing.

 

[pburgh19]

The power supplying the first 3-way switch would be from a 2-wire one hop back in the circuit. In other words, my wall box currently has an unterminated cable with black, white, and ground wires. The remainder of the circuit is on unfinished until I figure this part out, but it's just a few more unswitched receptacles. Does that get you to where you could show me a diagram?

I was thinking about it wrong in the first place it seems. I had envisioned a switch at each end of the circuit. It sounds a lot easier as you described it -- going switch to switch then to the first outlet.

So in your example... the two 3-way switches (we'll call them switch1 and switch2) have a 3-wire running between them. At switch1, the hot (black) from my 2-wire connects to the common screw. Black and red from the 3-wire connect to the traveler screws. The two whites at switch1 get nutted. Grounds at switch1 get nutted and connected to switch1's ground screw.

At switch2, the black and red from the 3-wire connect to the travelers. Crap... now this is where I get lost. I know I'll need a 3-wire headed out of switch2 to go the the first receptacle (since I want to do half-hot receptacles), but does switch2 have a wire that is constantly hot? It seems like it doesn't.

 

[pburgh19]

Here is a very basic drawing of how the room is currently wired. In a nutshell, 12/2 cable comes in to a 20A switch -- so I can shut off the entire room if I need to -- which then goes to a GFCI. The GFCI feeds power to a receptacle a few feet down the wall, and then on from there. The dotted line is a 12/2 cable currently run from outlet 2 to where I want the first 3-way switch. No other wiring exists in the room. The two receptacles in the middle of the drawing are the ones I want to control with the 3-ways (half hot). I hope this helps.

 

[joed]

What about receptacle 3&4? How do you want them? Do the new receptacles need to be GFCI. If this is finished basement they do not by code need GFCI.

You can't get power from switch 1 as there no neutral.
Right now it looks like the best option is GFCI 12/2 to 3way #2, 12/3 to 3way #1, 12/3 from 3way #2 to outlet6 then 12/3 from outlet 6 to outlet 5.

 

[joed]

Replace the lights with receptacles.
Bring power from the GFCI to get GFCI protection and be controlled by the 2nd switch. If you don't want switch control then take power from the 2nd switch box. The GFCI won't be protecting the new receptacles however.

NOTE I forgot half switch. Stay tuned for new drawing.

 

[joed]

new drawing , half switched receptacles.

 

[pburgh19]

What about receptacle 3&4? How do you want them? Do the new receptacles need to be GFCI. If this is finished basement they do not by code need GFCI.

You can't get power from switch 1 as there no neutral.
Right now it looks like the best option is GFCI 12/2 to 3way #2, 12/3 to 3way #1, 12/3 from 3way #2 to outlet6 then 12/3 from outlet 6 to outlet 5.

I expect receptacle 3 will be connected to the available wiring in the switch 1 wall box. Receptacle 4 would be connected to receptacle 3. This is an outdoor shed, not in the basement... that's why I have the 20A switch as a main disconnect for the space.

I don't understand this comment you made:

"You can't get power from switch 1 as there no neutral."

There's a neutral in the switch 1 box. It comes from receptacle 2, right?

 

[rjniles]

The last sketch by joed does not include a neutral in the dead ended switch. Required by current code. Run a 4 wire cable between the switches.

 

[pburgh19]

The last sketch by joed does not include a neutral in the dead ended switch. Required by current code. Run a 4 wire cable between the switches.

The 4th wire would provide un-switched hot between the switches, correct?

 

[joed]

You said sw1 has 12/2 from the receptacle. That means it is a switch loop. White is being used as a hot for the switch.

 

[rjniles]

The 4th wire would provide un-switched hot between the switches, correct?

Nope, the 4th wire gets the neutral to the far end switch. A non switched hot is not required at that switch. Actually it is already there on the white wire in joed's sketch.

 

[pburgh19]

Nope, the 4th wire gets the neutral to the far end switch. A non switched hot is not required at that switch.

Oh, my mistake! Thanks

I don't think I understand the drawings Joed provided. I'm used to looking at diagrams like this:

I'll look at the images again, but I still don't have a handle on how I get an un-switched hot in to the two half-hot outlets (center of my drawing).

 

[joed]

The black is unswitched. The red is switched. You need to cut the tab between the gold screws.

Note power coming in from top on black and white. Black continues on the receptacles without going to switch. White carries power to far switch.

 

[rjniles]

Oh, my mistake! Thanks

I don't think I understand the drawings Joed provided. I'm used to looking at diagrams like this:

I'll look at the images again, but I still don't have a handle on how I get an un-switched hot in to the two half-hot outlets (center of my drawing).

To use your example, you need a 4 wire cable between the switches (to bring the constant hot from the left switch to the right switch) and a 3 wire cable from the right switch to the first and second receptacle (to extend the constant hot.)

 

[pburgh19]

To use your example, you need a 4 wire cable between the switches (to bring the constant hot from the left switch to the right switch) and a 3 wire cable from the right switch to the first and second receptacle (to extend the constant hot.)

Ok, using a 4-wire makes sense to me. That way I've got the travelers + constant hot.

 

[pburgh19]

I suppose it would be ok to use a 3-wire between the 3-ways and a 2-wire alongside, or from a receptacle closer to switch 2, to provide the constant hot? I ask because I have a ton of 12/2 and 12/3, but no 12/4 handy.

 

[rjniles]

I suppose it would be ok to use a 3-wire between the 3-ways and a 2-wire alongside, or from a receptacle closer to switch 2, to provide the constant hot? I ask because I have a ton of 12/2 and 12/3, but no 12/4 handy.

Not really, it is a code violation. All conductors from a circuit must be in the same cable sheath or raceway.

Go to an electrical supply house and they will cut the length you need.

 

[joed]

Is this finished space? If not the the neutral is not required as the wall will be open to add it if needed later.

 

[pburgh19]

Is this finished space? If not the the neutral is not required as the wall will be open to add it if needed later.

No, not a finished space. Just a studded construction.