4 way switch

[Taylorjm]

Hi. So I have a 4 way hall light. It has the 3 way switches on each end of the hall and the 4 way switch in the middle of the hall. I've looked at wiring diagrams and will have to verify if it's wired correctly next time I go to the home. It's a vacation home. What I encounter, is when the switches are in certain combinations, the light won't go on at certain switches. Example, end switch is up, middle is down, other end switch won't work. I'm not sure on the exact combination, I'd have to play with it again. I think using the middle 4 way switch is messing things up. If we just use the end switches, we are fine. Is this normal? That certain combinations of the switches will allow the light to go on?

 

[wwhitney]

With (2) 3-ways and any number of 4-ways, properly wired, flipping any one switch will always toggle the state of the light.

If one position of the 4-way allows both 3-ways to act as above, but the other position of the 4-way does not, then I would guess something is miswired at the 4-way.

The 4-way is supposed to swap the travelers. I.e. if you have travelers A and B coming from one 3-way, and travelers A' and B' coming from the other 3-way, then one state connects A - A' and also B - B'. The other state then connects A - B' and also B - A'.

As far as wiring diagrams, conceptually simplest (to me) is where power comes into one 3-way, travelers to the 4-way, travelers to the other 3-way, and the load is at the other 3-way. But in practice power could be coming into any of the 3 boxes (or the ceiling fixture!), and the load could be supplied from any of the 3 boxes. So the 4-way box should have at least 3 conductors (plus ground) going to each of the 3-way boxes, but it could also have incoming constant power and/or power out to the load.

Cheers, Wayne

 

[Sponsor]

 

[Taylorjm]

With (2) 3-ways and any number of 4-ways, properly wired, flipping any one switch will always toggle the state of the light.

If one position of the 4-way allows both 3-ways to act as above, but the other position of the 4-way does not, then I would guess something is miswired at the 4-way.

The 4-way is supposed to swap the travelers. I.e. if you have travelers A and B coming from one 3-way, and travelers A' and B' coming from the other 3-way, then one state connects A - A' and also B - B'. The other state then connects A - B' and also B - A'.

As far as wiring diagrams, conceptually simplest (to me) is where power comes into one 3-way, travelers to the 4-way, travelers to the other 3-way, and the load is at the other 3-way. But in practice power could be coming into any of the 3 boxes (or the ceiling fixture!), and the load could be supplied from any of the 3 boxes. So the 4-way box should have at least 3 conductors (plus ground) going to each of the 3-way boxes, but it could also have incoming constant power and/or power out to the load.

Cheers, Wayne

Thank you. I'm going to remove the wall plates and pull out the switches and take some pictures of the current wiring and compare it to the diagrams. Sounds like something may be miswired, which is very possible since I replaced the 4 way switch that was bad and thought I wired it up the exact same way, but who knows! Thank you!

 

[Afjes]

Taylorjm:

First before you go pulling anything out of the boxes when you do be sure you do not remove any wires from the switches. Also of course be sure the power is off.

One thing I want to ask please - the 4 way switch - does it have "On" and "Off" imprinted on the face of it (the toggle).
If not fine. I just want to be sure that it is a 4 way switch. The person that installed it may have got hold of a 2 pole switch(has the exact same number of screws) and may have attempted to use that instead of an actual 4 way switch. This has happened before to even a few of my customers.

 

[Taylorjm]

Taylorjm:

First before you go pulling anything out of the boxes when you do be sure you do not remove any wires from the switches. Also of course be sure the power is off.

One thing I want to ask please - the 4 way switch - does it have "On" and "Off" imprinted on the face of it (the toggle).
If not fine. I just want to be sure that it is a 4 way switch. The person that installed it may have got hold of a 2 pole switch(has the exact same number of screws) and may have attempted to use that instead of an actual 4 way switch. This has happened before to even a few of my customers.

Thanks. Yup I'm sure it's a 4 way switch because I replaced it with exactly what was there. Honestly I don't know if it every worked correctly because when we bought the house I switched all the outlets and switches from the ugly ivory to white.

 

[Fitter30]

 

[Afjes]

I did not watch this video above ^^^^
but looking at the way the objects were identified in the diagram gets me wondering.

Hot leg coming in with a neutral, not a common. Those are not 2 way switches but 3 way switches. None of the switches should have "on" and "off" imprinted on them, if they do you have the wrong switches. They are not L1 and L2, they are travelers.

Do yourself a favor and take a look at some of this guy's videos. He knows what he is doing.
Benjamin Sahlstrom on youtube.com
https://www.youtube.com/@BenjaminSahlstrom

If you have any further questions please feel free to ask them.