3 way switches

[zdog]

If you look at both boxes, they're wired 'zactly the same. White wires tied together, black from 14/2 to common, red & black from 14/3 to travellers. That's the easiest way to train a cubby.

unless you get one i had once.had the 3ways made up all he hd to do ws put in the switchs.showed him how to hook them up.none of them worked all was hooked up wrong. i asked him why he did that he said he must have had the switch upside down

 

[roger3829]

Wow. What is going to happen if we put a couple of 4-ways into the circuit??

Can we wire those?

Can we put the feed into one of the 4-way switches???:roll:

 

[480sparky]

Can we put the feed into one of the 4-way switches???:roll:

 

[Dennis Alwon]

Can we put the feed into one of the 4-way switches???:roll:

Sure Sparky showed you how but if you are using NM cable #14 gauge you better install a 22 cu. inch box. :smile:

 

[480sparky]

Sure Sparky showed you how but if you are using NM cable #14 gauge you better install a 22 cu. inch box. :smile:

Or 24? in? for all you 12-only fans.

 

[roger3829]

Your picture wouldn't load on my computer.

But I know that you can feed either a 3-way, a 4-way, or the light. It doesn't make any difference. The biggest concern would be box size as was pointed out.

I have done it all sorts of different ways. It depends on the layout of the area.

 

[sguinn]

I figured I would add my two cents. I have done three-ways every whichaway at different times at different companies, everyone has their preference on which to make them up. Mine, which actually wasn't mine, I just found it was the best method that made the most sense to me, was simply having the hot, switch-leg, and 3-wire in one device box and then go from there with just a 3-wire to the other end of the 3-way, or even to a 4-way(s) in the middle. It makes trouble shooting easier and it also makes life more bearable when you're trying to introduce this concept to a helper with a little bit of green left on them before trying to explain the other methods for wiring 3-way switches.

 

[iaov]

Hey guys. Just got done for the day and was surprised to see this was still a subject of discussion. Thought when I said thanx to Bob & Dennis yesterday that would be it. Post #17 shows how I prefer to wire these circuits. I know several other methods but prefer this one. Usually its the easiest. Definately the easiest to troubleshoot/ repair. I drop switch legs out of fixtures frequently and hadn't thought of a 3 way like that. My question was if the other method , namely the dead-ending of the second switch was code compliant. Bob (iwire) and Dennis showed me the light (no pun intended) on this. As to the poster who wanted to know where I've been , they'll have to be a little more specific as to date and time.:grin:

 

[480sparky]

Your picture wouldn't load on my computer.

If you just see a little box with a red "X", try right-clicking it, then choose "Show Picture".

 

[kbatku]

A real puzzler....

A real puzzler....

I figured out a way to wire a "four way" circuit ( a three way and at least one four way switch) using noting but three ways.

It works in even combinations - four, six, eight three ways etc...

And they are all "dead end" three ways.

I'm going to do it someday because a) I can and b) someday it will really torment a service electrician who will look at the home owner and say "This can not POSSIBLY work!".

 

[LarryFine]

Hot feeds down on a black wire to one 3 way. The other black wire from the 2nd 3 way would feed the light. Red pair and white air from the 3 ways would be spliced respectively.

According to 200.7(C)(2), the white should only be used as the switch supply, and not a traveler. (Unfortunately the two-dead-end method makes compliance difficult.)

The inductive effect being canceled by the opposite polarity always existing in the neutral.

The current in a 2-conductor cable feeding (and returning from) a switch, commonly known as a 'switch loop', does the same thing. The current in the two conductors is equal and opposite, thus cancelling.

 

[LarryFine]

Here is a good one that I like to do for basement stairs,(works well with a fixture at the top and bottom of stairs) 3 way at the bottom of stairs has feed, I will run 3 conductor from bottom of stairs to bottom fixture, then pull a 4 wire out of the fixture to the 3 way at the top of the stairs, then I can pull another load out of the box at the top of the stairs...

I've done the same thing with two lengths of 2-conductor cable between top and bottom.

 

[LarryFine]

Bob, can you elaborate on this method? I'm having a hard time getting a visual. Your saying if you have a feed at the fixture you can run 2 wire to the first 3way and then 3 wire in between all the 4way/3ways and just dead end at the last 3way? What do you do about the common for the the 1st switch? Oh wait,,,,your saying run the 3 wire from the fixture box to rest of the devices and dead end them? Wow, Im embarrased not knowing this method that everyone else feels at ease with.
Im off to the white board.

Try it this way: the incoming white hits the load's grounded-conductor terminal, period.

The incoming hot hits the outgoing 2-conductor cable on the white, which continues on the whites through every switch box (all of which should be re-colored), and lands on the common of the last (3-way) switch.

Blacks and reds are used as travelers back and landing on each 4-way switch, and finally to the first (3-way) switch, whose common supplies the black back to the load.

This is actually the same thing as how a single-switch switch-loop is wired: two 2-conductor cables in the load's box, with a black tied to a white.

 

[LarryFine]

The neutral stays in the light. The feed travels down on the white wire of the 2 wire cable. It then travels through to the last 3way as the point , let's say on the black wire. Thus the white from the two wire cable is taped black and connected to the black on the 3 wire.

The red and whites are the travelers. The black from the 2 wire cable connects to the first 3 way as the point & goes back to the light as the switch leg. Voila--- let there be light.

Again, the whites should all be used to carry the hot to the last switch, and blacks and reds used as the travelers.

 

[LarryFine]

What i have found is many electricians only know 1 way to do 3 ways and thats feed at one end and leg at other.No idea why they got hired.

The funny thing is that, no matter how the cables are run, how you described it is still how it's wired, electrically speaking.

 

[LarryFine]

Can we put the feed into one of the 4-way switches???:roll:

At the risk of sounding repetitive, this is another case where the black wire labeled "Must connect to common screw of 3 way switch" between the middle and right boxes should be white (but re-colored), and the black used as a traveler, as it is between the middle and left box.

 

[LarryFine]

You expect that? Their logic is more along the lines of "Hey, I can make it work just fine... that makes me a profeshunal 'lectershun."

I understand you point, however. Not only should you be able to install any (legal) method of 3-ways, you should eventually be able to troubleshoot any (legal or non-legal) method.

I concur. A couple of years ago, one of my guys, more experienced in EMT work, went to T/S an intermittent receptacle complaint. (I later figured out it was a pair of split-wired receptacles wired to work together from a pair of 3-ways.)

The receptacles in question (stab-wired) needed replacing anyway, so he unhooked every wire from both. Then, he had no idea how to connect the wires to the new receptacles. Naturally, he hadn't made a diagram or anything.

So, he called me (which he didn't enjoy) to help him. I took about two minutes of looking in the boxes, and figured out how they should be wired, and told him what to do. He never understoood how they worked, but they did.

 

[ptonsparky]

It also reminds be of the guy I had working with me.. I would drill the house out (and with 1 wire per hole its alot of drilling with the shotgun) :grin: then I would layout my helper...The house had several sets a three ways and I drilled them out several diff ways depending on what was easiest...Next thing I know he has got the drill out, drilling away, I thought I must of missed some holes...When I went to check his work he changed every 3W to the same way..apparently he only knew 1 way..........

Had this problem with my #1 help as an apprentice. Now that he has some years of experience and knows I am not set on just one way, he can get creative. I don't think we wired a new home last year and only remodeled a 4 unit apartment so having a different crew p&s after rough in is not a problem.

 

[Dennis Alwon]

According to 200.7(C)(2), the white should only be used as the switch supply, and not a traveler. (Unfortunately the two-dead-end method makes compliance difficult.)

The current in a 2-conductor cable feeding (and returning from) a switch, commonly known as a 'switch loop', does the same thing. The current in the two conductors is equal and opposite, thus cancelling.

Where does 200.7(C)(2) say I must use the white as a switch supply. It does not say I must. It states if I do then.... IMO

 

[iwire]

Where does 200.7(C)(2) say I must use the white as a switch supply. It does not say I must. It states if I do then.... IMO

Dennis 200.7(A) says you can only use white for the grounded conductor, then 200.7(C)(2) says you can use the white for the supply to the switch.