Dimmers on 3-way

Discussion in 'Electrical Forum discussion & Blog' started by JMingrone, Nov 22, 2012.

  1. JMingrone

    JMingrone New Member

    Messages:
    49
    Location:
    Connecticut
    Question:

    I just wired my kitchen for two new 3 way circuits. Definitely want both to be on dimmers. I know they make 3-way dimmer switches, but what I don't know is if you can put the dimmer on both ends of the 3-way, or must one end have just a regular 3-way switch?

    Thanks,

    Jay
  2. jimbo

    jimbo Plumber

    Messages:
    8,997
    Location:
    San Diego
    Get the diagram for any unit you are thinking about. But YES....there are dimmers which can be used on both ends of a three-way. Remember that MOST dimmers can NOT be used for fluorescents or LED's. If the dimmer switch does not cost >$100, just assume it is not compatible with fluorescents.
  3. JMingrone

    JMingrone New Member

    Messages:
    49
    Location:
    Connecticut
    No flourescents. Using Xenon under cabinet lights for ease of dimming and warm light. 4" Recessed cans in ceiling use CREE LEDs which I tested with an el-cheapo dimmer and they work fine. BTW, the CREES have a negligible turn-on delay compared to HALO's (which have a 1/4 to 1/2 sec delay) and are only $30 compared to $50 for the HALOs.

    I know they have fancy master/slave/remote setups nowadays, but I ran standard 3-conductor cable for the new 3-ways and was hoping to get a plain-vanilla type switch that cam be dimmed from either end. Do they make simple ones?

    Also, if you do have dimmers on each end does the dimming "add", i.e., if each was set for 50%, do you get 25% light?

    Thanks,

    Jay
  4. jimbo

    jimbo Plumber

    Messages:
    8,997
    Location:
    San Diego
    No, just as with a conventional switch, on end or the other will be placing the light on and dimming it
  5. LLigetfa

    LLigetfa DIYer, not in the trades

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    4,049
    Location:
    NW Ontario, Canada
    One problem with 3-way dimmers is that if you dim one side all the way down but don't click it to off, it cannot be controlled from the other side.
  6. JMingrone

    JMingrone New Member

    Messages:
    49
    Location:
    Connecticut
    Hmmmm... Didn't realize that 3-way dimmers had an "off" as well. So i guess I'm still unclear how two 3-way dimmers interact. Guess I'll have to pick a few up and try them.
  7. LLigetfa

    LLigetfa DIYer, not in the trades

    Messages:
    4,049
    Location:
    NW Ontario, Canada
    Every 3-way dimmer I've installed has 3 states; On, Off, and dimmed. When one side is dimmed, the other side can only control On and Off. Maybe there are other types out there but I have not come across any that can vary the brightness while the other end is.
  8. Chad Schloss

    Chad Schloss Member

    Messages:
    330
    Location:
    USA
    the leviton vizia 3 ways dim at either end. i installed 3 pairs of them in my rental house.
  9. LLigetfa

    LLigetfa DIYer, not in the trades

    Messages:
    4,049
    Location:
    NW Ontario, Canada
    I have no experience with that model but the dimmers I have experience with can dim at either end provided the far end is in the full Off position.

    Do you have a link to the model that allows dimming from both ends at the same time?
  10. jimbo

    jimbo Plumber

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    8,997
    Location:
    San Diego
  11. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,126
    Location:
    New England
    The Leviton Maestro series can have as many as 8 dimmer switches controlling the same circuit...there's one 'master' that has LED's that show the level of dimming, but you can control both on/off and dimming at any of the other (slave) switches in the circuit. It only needs a 3-wire cable between all of them. I have three of them to control my counter lights, overhead lights in the kitchen, and another in the dining room. You can (or at least could) buy them at HD. HD sells them in a two pack with a master/slave, but you can buy additional slave units. They take a Decora switchplate.
    Last edited by a moderator: Mar 18, 2014
  12. LLigetfa

    LLigetfa DIYer, not in the trades

    Messages:
    4,049
    Location:
    NW Ontario, Canada
    Sounds expensive. I stand corrected.
  13. JMingrone

    JMingrone New Member

    Messages:
    49
    Location:
    Connecticut
    So, sounds like 3-way dimming works a little differently than I first thought. Initially I assumed both ends of the 3-way were identical parts in the same way that non-dimming 3-ways are: buy 2 of the same parts and install them at each end. My understanding now (correct me if i'm wrong) is that to do dimming from multiple locations, only ONE of the switches actually does the dimming, the other(s) communicate dimming level (input at the alternate locate) to the actual dimmer. Either end can turn the lights ON or OFF, and either end can dim, exactly what you want. Do I have that right?

    Regardless of how it actually works, does it still use a 3 conductor cable running between the 2 locations? Hope so, because that's the way I wired it.

    An alternate mode i'm considering if dimming from both ends isn't possible (with my current wiring) is dimming from only one end, and having on/off control from the other end.

    Thanks,

    Jay
  14. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

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    22,126
    Location:
    New England
    Basically, as I understand it, one of the three wires is a signalling wire that talks from one of the slaves to the master. So, yes, all you need is a 3-wire cable connecting them all with a two-wire cable to the light fixture(s). It gets a little more messy if the power is at the lights, then needs to go to the switches, but it's all shown in the installation instructions.

    If you're using this to control a low-voltage system, you need a special version of the dimmer. It makes a difference whether that low-voltage system uses a magnetic or electronic circuit to make the low-voltage and those dimmers do cost more than for just incandescent lights (I needed one of those for my situation). From what I remember, one master/slave pair was around $50 at HD, but I bought mine about 5-years ago.
  15. LLigetfa

    LLigetfa DIYer, not in the trades

    Messages:
    4,049
    Location:
    NW Ontario, Canada
    You can buy 3-way dimmers that work the way I describe. You can also use a 3-way dimmer on one side and a 3-way switch on the other. As Jim said, you can also get the system with master and remotes (slaves is not PC).
  16. JMingrone

    JMingrone New Member

    Messages:
    49
    Location:
    Connecticut
    I think the restriction about one end being in the off position to dim from either end would be a nuisance, but just for grins, do you have a make/model for the type you describe?
  17. LLigetfa

    LLigetfa DIYer, not in the trades

    Messages:
    4,049
    Location:
    NW Ontario, Canada
    I don't recall the brands. I replaced all of the original ones with a different brand because they were noisy. Because of the limitation, I ended up putting the dimmer on just one end and replaced the less used end with just a regular 3-way toggle. Still to this day, I will sometimes go to flick on the toggle but the far end dimmer was set to dim and not clicked all the way to off. If it annoys enough, I might try some of those master/remote versions that Jim mentioned. First though, I will mention to the wife, the high price in the hopes it can somehow dissuade her from leaving the far end on dim instead of off.

    Meh... that'll never happen. Now, if only I could get her to leave the toilet seat up for me. Oh, and never, ever opt for one of those double wide garage doors... the wife will always park right in the middle, taking up both spaces.
  18. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,126
    Location:
    New England
    Put a support pole or something in the middle...
  19. JMingrone

    JMingrone New Member

    Messages:
    49
    Location:
    Connecticut
    Coincidentally, I just put a double wide garage door in. Won't know how it works out until I get my new kitchen cabinets and appliances out of there......
  20. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,797
    Location:
    Cave Creek, Arizona
    The idea behind a 3way switch is that you can turn it on at one location and turn it off at the other. If you have to turn one "off" before the other will work, that pretty much negates the reason for having it as a 3way. Logically, if one switch has dimmed the lights, you cannot go to the other end and expect to "undim" them since the power only comes from one end or the other, and once it is "reduced" you cannot increase it at the other end.
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