2 way switch not working right

Discussion in 'Electrical Forum discussion & Blog' started by augusta, Jan 1, 2010.

  1. augusta

    augusta New Member

    Messages:
    97
    Location:
    Augusta GA
    I have a couple of two way switches that have been working fine for years. A few days ago they started not working right. I can turn on the light from either location, but I can only turn it off from the location where I turned it on. Is this common? Does it mean one is bad? If they both behave the same, how would you know which one to go to first to troubleshoot?

    Thanks for any help.
    Last edited: Jan 1, 2010
  2. jimbo

    jimbo Plumber

    Messages:
    8,997
    Location:
    San Diego
    Could be either switch bad, or some wiring problems. If no one has worked on this ( to possibly install an incorrect switch or mess with wires) then I would replace both switches and be done with it. BE CAREFUL> the arrangement of the terminals on the new switch will likely be different than the old one. A terminal with a black screw is the common, and the other two are the travelers. Make sure to get the common wire to the right terminal.
  3. augusta

    augusta New Member

    Messages:
    97
    Location:
    Augusta GA
    Thanks. Will do what you said. I just thought it strange that the switches behave the same way. It doesn't seem that they are broken, just both doing exactly the same thing. Can turn on the light from either location, but have to cut it off from the location where I turned it on. Otherwise the switch flip does nothing from the opposite location. I thought that maybe this was a common thing to identify for folks who work on electrical.

    No one has been doing any electrical work. I'll buy two new switches, paying attention to the black screw and see what happens. Thanks again.
  4. Billy_Bob

    Billy_Bob In the Trades

    Messages:
    422
    I think you have "3-way switches". I would replace both of them. One switch probably has a bad contact inside the switch, but the other switch is probably about to wear out anyway, so best to replace it too.

    3-way switches look like the switch on the right in the following picture. Is this what you have?

    [​IMG]
  5. augusta

    augusta New Member

    Messages:
    97
    Location:
    Augusta GA
    3 way switch? I thought if you are only switching from 2 locations, then the switches were 2 way switches. I have no clue. I have pictures though. Attached.

    By the way, both switches have the black screw. On the second photo, the black screw is on the top right, hidden from view point.

    Attached Files:

    Last edited: Jan 1, 2010
  6. codeone

    codeone Code Enforcement

    Messages:
    160
    Location:
    North Carolina
    Your pictures are of Three way switches, the black screw is your common terminal. In your first picture you see the wire in the bottom is looped around the black screw. That is your power feed so the black screw on the top of the other picture goes to your light.
  7. Cass

    Cass Plumber

    Messages:
    5,980
    Location:
    Ohio
    They are 3 way switches....even though there are only 2
  8. jimbo

    jimbo Plumber

    Messages:
    8,997
    Location:
    San Diego
    Perhaps we will have an electrical historian explain exactly why these are called 3-way. And if you need to control lights from THREE locations, you need a FOUR WAY switch!
  9. augusta

    augusta New Member

    Messages:
    97
    Location:
    Augusta GA
    I'll be the first to admit that I need to take a class in the basics of electricity. Maybe I will soon. Thanks for the help. I'll go buy (2) 3way switches and replace these (2) 3way switches. I don't know if the terminals will match up exactly with the new switches. Meaning, I don't know why the red wire is on the same side of the switch as the side with the black screw on one, but the red wire is on the opposite side of the switch of the black screw on switch two. Guess I'll just try to match up and if that doesn't work, I'll just keep switching wires until I get it right.

    Thanks again.

    P.S. if it is common for newbies to confuse 2 way switches with 3 way switches, can we put a sticky up explaining the difference?
  10. Billy_Bob

    Billy_Bob In the Trades

    Messages:
    422
    That's a good question as to why they are called 3-way switches!

    I found something which explains this...

    Following from...
    http://www.act-solutions.com/PCC/kingery06.htm
    ["Have you ever wondered why they are called "3-way circuits" when there are only 2 switches? Well, it has to do with the number of "drop points" and not the number of switches in the circuit. You see back in the early days of electrical wiring, back in the days of Thomas Edison, the vocation of "electrician" was brand new. These new electricians would base their cost estimates partly on the number of "drop points" on each circuit. A drop point could be a switch, a load or any junction point. In a sense a circuit with only 1 switch and 1 load would be a "2-way". I suppose this was because the wires had to go "two different ways". A circuit with 2 switches and 1 load would be "3-way". Incidentally, a circuit with 1 switch and 2 loads would also be a 3-way, but over the years, the label of "3-way" has evolved into meaning any circuit with 2 switches in it."]
  11. frenchie

    frenchie Jack of all trades

    I always though it had to do with the possible states of the circuit.

    2-way circuit has 2 possible states:
    - on
    - off

    3-way circuit has 3 possible states:
    - on (through the first traveler)
    - on (through the 2nd traveler)
    - off

    and so on.
  12. augusta

    augusta New Member

    Messages:
    97
    Location:
    Augusta GA
    Hey, thanks for the help fellas. I replaced both 3 way switches today and now the light works like a champ.

    I wish I had known to open the box of the new switch before I bought it though. It seems that not all of the new 3 way switches have that slot where you can stick the wire in without using the terminal. For $4.79 each from Home Depot, I would have thought they'd have both the slot and the terminal. Mine didn't. It's just a little difficult to combine both the looped wire with a second wire on the same terminal but I man handled it. Thanks again.
  13. frenchie

    frenchie Jack of all trades

    Late now, but... you should combine them under a wire nut, instead, with a third, short length of wire leading to the terminal. It's called a "pigtail". Like so:

    [​IMG]
Similar Threads: switch working
Forum Title Date
Electrical Forum discussion & Blog Question regarding wireless light switch Oct 15, 2014
Electrical Forum discussion & Blog Converting Two Recessed Lights on a Single Switched Leg Jun 16, 2014
Electrical Forum discussion & Blog a single 3-way switch controlling a light fixture on a knob & tube circuit - why? Jun 12, 2014
Electrical Forum discussion & Blog 3-way switches with dimmers for lighting? May 2, 2014
Electrical Forum discussion & Blog 1 circuit/2 gang 3 way switches- Does this look right? Apr 17, 2014

Share This Page