Light on three- way switches does not work

Reply

  #1  
Old 06-13-05, 06:56 AM
pwg
Visiting Guest
Posts: n/a
Lightbulb Light on three- way switches does not work

I have a light fixture controlled by two- three way switches. Recently the light started working only a low percentage of the time. So I replaced the fixture and both three way switches. Now the light does not work at all. It appears to me that the wiring must be bad, do you agree? What is the best way to determine which wire(s) are bad and also verify that the three way switches are wired properly? Is there anything else to check? All other lights and recepticles on this circuit work without any problems.
 
Sponsored Links
  #2  
Old 06-13-05, 07:06 AM
Member
Join Date: Sep 2003
Location: Central New York State
Posts: 13,973
I would first suspect that you installed the new three way switches improperly.

When you replaced the switches, did you connect the wires to the new switches the same way, not by wire position but rather by screw color? There are two traveler screw terminals and one common screw terminal. The screw colors will identify these terminals. They are not necessarily in the same position on all three way switches.

To test for proper connection, you must verify power. How you do this depends on whether the switches are wired as a switch loop (no neutral) or if power passes through the switches (there is a neutral at the switches), and whether there is a ground or not.
 
  #3  
Old 06-13-05, 07:24 AM
pwg
Visiting Guest
Posts: n/a
When I replaced the three way switches I was very careful to place the common wire from the old switch to the common of the new switch. Ground is also the same.

The other two screws on the new switches are gold. The old switch had one gold and one silver screw. Since the new switch had two gold screws I assumed it did not matter how these wires were installed. Is that correct.

Since all the wiring is hidden in walls how do I determine if the wiring is switch loop or through switches?
 
  #4  
Old 06-13-05, 07:32 AM
Member
Join Date: Sep 2003
Location: Central New York State
Posts: 13,973
Something is wrong with your setup or your analysis of the setup.

A three way switch requires three wires (not counting the ground wire) to function properly. The other three way switch also requires three wires (not counting the ground wire) to work.

Not counting the ground screw (which should be green), there should be two screws of the same color and one of a different color. The colors of these screws is not important. They may be brass, silver, black or whatever. You do not look for and connect to the same color screws from switch to switch. You connect the two travelers to the same colored screws and the common wire to the odd colored screw.

It sounds like you are in over your head.

Describe all the wires in each switch box and at the light and we can sort it out. Be specific. What cables exist and how were the wires connected to the original switches. What color are the wires and from what cable do they come from.
 
  #5  
Old 06-14-05, 04:44 AM
pwg
Visiting Guest
Posts: n/a
Both three way switches are wired the same. The purple wire goes to "common" the black screw. The bare ground wire goes the green hex screw. The red and white wires each go to a gold screw.

There is a black, a white and a ground wire to the fixture.

All wires are installed tightly.

Assuming the wiring is correct the reason I believe the wires themselves are bad is because before replacing the fixture and switches the light worked only a low percentage of the time. Now that I have worked on the system and maybe loosened some wire more the light does not work at all.

Any suggestions?
 
  #6  
Old 06-14-05, 04:57 AM
Member
Join Date: Sep 2003
Location: Central New York State
Posts: 13,973
Describe all the wires in each switch box and at the light and we can sort it out. Be specific. What cables exist and how were the wires connected to the original switches. What color are the wires and from what cable do they come from.
 
  #7  
Old 06-14-05, 10:43 AM
Member
Join Date: Sep 2002
Location: welland ontario
Posts: 5,599
If you have purple wires on your common screws and no purple wires in the fixture box then you have another junction box on this circuit somewhere. At least one of the common screw wires goes to the fixture. The other common screw wire goes to the power source.
 
  #8  
Old 06-15-05, 04:33 AM
pwg
Visiting Guest
Posts: n/a
I took a good hard look at the wiring. This is the way it is, excluding the ground.

At the switch box remote from the light there is one set of three-wires. The black wire goes to common the red and white wires go to the other two screws on the three way switch.

At the box close to the light there are three sets of wires. Set number one has three wires white, red and black, I assume this is the same set of wires that goes to the other switch. Set number two is white and black, I assume this is power. Set number three is white and purple, I assume this goes to the light because the light also has white and purple wires. The white and red wires from set number one connect to gold screws on the three way-switch. The black wire from set number one connects to the black wire from set number two (power). The purple from set number three (the light) connects to the common on the three way switch. The white wire from set two (power) connects to white from set three (light).
 
  #9  
Old 06-15-05, 04:59 AM
Member
Join Date: Sep 2003
Location: Central New York State
Posts: 13,973
This sounds like the wiring is correct.

Now use a tester and verify power at each stage of the wiring, appropriate for the setting of the switches.

In other words, verify power on the white and black. Then verify power at the common of far switch (use the ground here, since you have no neutral). Then at the travelers of the far switch. Then at the travelers of the near switch, then at the common of the near switch, and finally at the light.
 
  #10  
Old 06-16-05, 04:38 AM
pwg
Visiting Guest
Posts: n/a
Last night I found the problem. No power. First I checked the switch from common to travelers I had continuity but no volts. When I checked the black/white set of wires (set number two) with my voltmeter again I got zero volts. Yes the power was on. I have no idea what happen to the wire.

In the box that is close to lights (see previous thread) is another three way switch. This switch is part of a four-way lighting circuit and is on a different power circuit. For this switch there are two sets of wires a white/purple set and a white/red/black set. The white wires connect to one another, the purple goes to common on the switch the black and red wires go to the other screws on the switch. Here is my dream, finding a way to obtain power from the three-way switch on the four-way circuit to power the circuit that does not work. Can you make my dream come true? I suggested to my wife to eliminate the bad circuit and run that light off the circuit that works. She didn't like that idea.

If all else falls I have a means of providing power to the bad circuit by backfeeding from the light. I have a diagram showing this.

Thanks for all your help.
 
Reply

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread
Display Modes
'