4-way switching

J

JoeNorm

Senior Member
Location
WA
I know there are multiple ways to wire a 3-way switch. I commonly use the standard Power......3 wire........Load technique to keep things simple but I also use a "dead end" occasionally.

My question is about 4-ways. Do they have any variations like 3-ways? Or is it always going to be power in, 3wire between multiple switches, out to load?
 
Yes there are many ways to wire both 3-way and 4-way switches. The linear In>Travelers>Out Method is the simplest and easiest to troubleshoot. You could just run a 4-wire cable from the 4-way to either 3-way to make it work.
 
All the switching is done in the travelers on a 4 way switch. You shouldn't have your constant hot common or switchleg common terminated on your 4 way. I'm sure there are very confusing ways to wire them another way but I prefer to wire them as simple as possible so anyone can come behind me and easily figure out what I have done.
 
hillbilly1 said:
The four way(s) are always in the middle. They will not work any other way.
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That's true. You don't have to run the cables from the 3-way to the 4-way to the 3-way although it is less confusing to do it that way. Same for 3-ways. It is nice for the next guy to run the wiring the most obvious way for troubleshooting.
 
When I was a kid my father put the nm feed, nm from the light and the two 14/3 in one box, didn't mark anything and had me figure it out. That was the day I knew I wanted to be an electrician as a career. That was fun.
 
Great question — and you're spot on that 3-ways offer some flexibility depending on where the power and load are. With 4-ways though, it's pretty locked in by design.


There’s basically one way to wire a 4-way switch setup: it always goes between two 3-way switches. So you’ll still have:


Power → 3-way → 4-way(s) → 3-way → Load


The key difference is just how many 4-ways you add in between. Each 4-way takes in the two travelers from the previous switch and sends them back out, just crossed internally depending on switch position. No variation in wiring methods like you see with 3-ways (like dead-ends, switch loops, etc.). It’s all about traveler continuity.


The only real "variation" might be how the boxes are physically laid out — like if you're roughing in for conduit or using a junction box nearby — but electrically it stays the same.


And if you’re ever hauling prefab switch legs or trying to keep consistent parts across jobs, ordering stuff like pre-assembled switch boxes or larger conductor spools across provinces can save time. Just make sure it goes through freight ground shipping so you get full-length rolls and they don't split the order up or damage it in transit.
 
acrwc10 said:
When I was a kid my father put the nm feed, nm from the light and the two 14/3 in one box, didn't mark anything and had me figure it out. That was the day I knew I wanted to be an electrician as a career. That was fun.
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When I was a kid in the fifth grade, I did a 4H project for DPA. I was to wire two three ways and a four way to light a porcelain lamp holder. Wired it exactly the way the four way box shown, wouldn’t work. I took a battery and a light (didn’t have a meter) and figured out how the four way worked. The box had the incorrect diagram. There are two ways a four way can work, depending on the manufacturer. Switching top to bottom, or switching left to right.
 
JoeNorm said:
Ok, glad to hear there is only the one way to do it. Keeps things simple.
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With the 4-way(s) there is one way to physically connect the wires but there are many ways to run the wiring between the device locations. Some simple, some complicated.
 
Ok but here's the wrong way. I've seen it for real
1 circuit
Power 2 wire to 3 way switch and Power from there to light. 2 wire through 4 ways and to last 3 way then 2 wire switch leg.
Nuetral from first 3 way switch is tied to the light and power from the last ones 3 way is tied to the light with nuetral tied through and capped at last 3 way. No go now but it works I've seen it.
 
hillbilly1 said:
There are two ways a four way can work, depending on the manufacturer. Switching top to bottom, or switching left to right.
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If you remember that the two dark terminals go to one 3-way and the two light terminals go to the other 3-way, you don't need a diagram. I never consider the terminal positions on the switch body.
 
Look up the "California 3-Way" sometimes called the "coast 3-way". It could come in handy. There also an interesting, but illegal, setup called a "Carter 3-way".
 
With changes in the NEC regarding grounded conductors at switches using cable methods, (404.2) This has limited the ways that we used to be able to run them. I've seen some installations that really confused me and I've had to draw a picture or use my ohmmeter to verify that I have all the conductors needed for operation. I personally like that the grounded conductor has to be at one of the switches in 3W-4W-3W applications because I tend to get a little aggravated when I get shocked by what should be an equipment grounding conductor.
 
Funny, but I look at it differently. There is only ONE WAY to wire 3 way switches, power to one two travelers between them and switch leg out of the other. Everything else is means and methods.
 
Strathead said:
Funny, but I look at it differently. There is only ONE WAY to wire 3 way switches, power to one two travelers between them and switch leg out of the other. Everything else is means and methods.
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That's true logically (at a schematic level), but once you introduce physical enclosures, there are multiple ways to route the cables.

Say we have two switch locations (initially considered equivalent for counting purposes) and one lighting location, and we're going to wire it up without power passing through to further loads, and without surplus cables. Then we can either bring power to the light or to a switch.

If we bring the power to the light, then we need a cable from the light to a switch (they are equivalent, so only one choice here). The other switch can connect to the light or to the switch already connected. So 2 possibilities here.

If we bring power to a switch, then one option is connect from there to the light. The final switch can connect either to the switch with power or to the light. So 2 possibilities here.

Or with power to a switch, the other option is to go directly to the other switch. Then the light can be connected to either the switch with power, or to the other switch. But the configuration with the light connected to the switch with power was already counted. So just one new possibility here.

That makes a total of 5 ways to do the wiring, when you consider the switch locations initially equivalent.

Cheers, Wayne
 
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