Full Answer
What is a 3 way switch used for?
Three-way switches are commonly used to control a light fixture from two different locations. For example, a long hallway or stairway might use a pair of three-way switches at each end so that lights can be turned on when approaching one end of the hall or stairway, then shut off from the other end.
What is the working principle of 3 way switch?
Understanding Three-Way Wall Switches
- Parts of a Three-Way Switch. The green screw attached to the metal strap of the switch is always for the ground wire (this is the bare copper or green insulated ...
- The Grounding Screw Terminal. For safety, always install a three-way switch that has a grounding screw. ...
- Three-Way Switch Wiring. ...
How to wire a 3 way switch diagram?
Install A Three-Way Switch
- Three-way switch
- Three-way cable with another for ground wire (four total)
- Terminal screws
- No.12 wire
- Lineman's pliers or hacksaw
- Sharp knife or slitting tool
- Wire strippers
- Hand brace
- Drill with long auger electrician's bit
- Coil of electrician's fish wire
How do you replace a 3 way switch?
Steps:
- Start by turning off the power to the circuit you'll be working on at the main electrical panel.
- Test the switches with a voltage tester to ensure the power is off.
- Remove the cover plate from the switch box with a slotted screwdriver.
- Unscrew the three-way switch you suspect isn't operating properly from the box.
Why is only one of my 3-way switches working?
Identifying the common wires... Sometimes, a 3-way circuit doesn't work because someone tried to replace a defective switch and did not properly connect the wires. Sometimes, one of the switches has become defective.
How do you fix a 3-way improperly wired switch?
Turn the power back on at the circuit breaker. Touch the probes to the 3 wires removed from the switch until you get a reading on the tester indicating continuity. The third wire is the common wire that feeds the light fixture and is connected to the black screw on the switch. Replace both switches and covers.
Is there always a hot wire on a 3-way switch?
Black wire: This is a hot wire that carries electricity from the power source to the first switch in a typical 3-way setup. It's also called the “common wire” or the “line wire.” Unless the breaker is off, this black wire is always hot.
Can a 3-way switch stop working?
Usually when a 3-way switch fails, lights can be toggled on and off at one switch, but not the other. If one of the two 3-way switches toggles the light(s) on and off, the other 3-way switch has probably failed. Follow these steps to find which switch is bad. Toggle each switch until the light come on.
What happens if 3-way switch is wired wrong?
If you don't correctly connect this wire, then your lights won't work from more than one switch. Grounding the switch: You'll also need to locate the ground wire and connect it to the switch too.
How do you troubleshoot a 3-way circuit?
0:404:543 Way Switch Troubleshooting - YouTubeYouTubeStart of suggested clipEnd of suggested clipPut a piece of tape on each of the wires. It does not make any difference which wire gets whichMorePut a piece of tape on each of the wires. It does not make any difference which wire gets which piece of tape.
How do you test a 3-way switch?
1:032:57Testing your 3-Way Switch using an Ohm Meter - YouTubeYouTubeStart of suggested clipEnd of suggested clipNow we move the switch to the top position you can hear the tone. And you can see the meter. IsMoreNow we move the switch to the top position you can hear the tone. And you can see the meter. Is going to all zeros. Here. We have a good connection on this side of the switch.
Can you take constant power from a 3-way switch?
To use the 3 way for power you need to check 2 things: 1) as stated above, make sure you have the neutral wire available in that particular switch box (white wires, probably at least 2 joined together w/ a wire nut-NOT CONNECTED TO THE SWITCH) #2 even if there are neutral wires available, usually one of the two 3 way ...
What is black screw on 3-way switch?
This screw serves one of two purposes depending on where it is positioned in the circuit run: Either it accepts the incoming black (hot) wire from the power source, or it connects to the black (hot) wire that leads onward to the light fixture.
Why does my light switch only work sometimes?
Even if this happens only occasionally, it's still time to replace the switch. It is also possible that the light fixture or switch has loose connections or a short circuit that causes intermittent failure, so if the problem persists after you've replaced the switch, have a look at the light fixture next.
Why would a 3 way switch trip a breaker?
A switch is in an improper position when the switch pole screw lies against the switch box and the runner is shorted, which causes the fuse to blow when you turn the lights off. Also, the breaker will trip if the runner short circuits to the ground or neutral wire somewhere along the wiring's terminus.
Do both switches need to be 3 way?
The key ingredient is a special type of switch called a “three-way” switch. You'll need two of them, one to replace the existing switch and another for the new switch location. With these, you'll have the convenience of turning a light on and off from two spots.
How to connect a 14/3 switch?
If one switch has only a 14/3 going to it, at that switch connect the black to the common, the red and white to the traveler screws. At the other switch, connect the black from the 14/3 to the black going to the light and the red and white to the traveler screws. Connect the constant hot black to the common screw of this switch.
What happens when a switch is down?
When the switch is Down, it connects the common and the bottom traveler. So, if power is going to the first common and the first switch is Up, then power goes down the top traveler until it gets to switch 2. If that switch is Up as well, then power goes from the Up traveler to the switch 2 common and on to the light.
What happens when you cross traveler 1 and traveler 2?
If you cross Traveler 1 and Traveler 2 between switches, all it changes is whether Up-Up means "On" or Up-Down means "On". If you switch the "travelers" and the light no longer works, then you misidentified the travelers or the common pole. imjayhawk.
What is the black wire on a switch?
The black wire that connects to switch1 is then connected to the light. Breaker ----> Switch2 -------> Switch1 -----------> Light. All this time, the black wires have always been connected to the switches' common. Since Switch2 has the hot coming in, at anytime either Red or White is hot going out of Switch2.
Can a 3 way switch be off?
The light will be on if one is up and the other is down. There is no off or on position on a 3-way switch. Look for the word common stamped on the switch, maufacturers put them in different positions.
Replaced 3-way switch, now it works only in one position
I've seen other posts regarding this but none that quite matched my scenario.
Comments (15)
The person who installed this cob job was no electrician. Using the bare wire for one of the travelers is NOT legitimate in any way.
What happens when a 3 way switch fails?
When a 3-way switch fails, there will usually be no continuity between the common terminal and one (sometimes both) traveler terminals of one of the 3-way switches. Place leads of continuity tester on the common (black) terminal and one of the traveler (brass or silver) terminals.
How to test a 3 way switch?
Test a 3-Way Switch 1 Turn off power to the switches at the circuit breaker and using a tester, make sure power is off. Remove the two 3-way switches so you can access the switch terminals. The wire connections do not have to be removed. 2 Using a continuity tester, check continuity between the common (black) terminal and each of the traveler terminals (brass colored) of each 3-way switch. 3 There should be continuity between the common terminal and only one of the traveler terminals. After toggling the switch, there should be continuity between the common terminal and only the other traveler terminal.
Why are switches spring loaded?
Switches are spring loaded to minimize arching and prolong their life. However, a very small amount of arcing is present when a switch is toggled. A bad switch may not fail completely, burned contacts may cause intermittent failure. Keep this in mind when troubleshooting switches.
How to tell if a switch is bad?
Follow these steps to find which switch is bad. Toggle each switch until the light come on. Toggle one switch to see if it turns the light on and off. If it does, it is a good switch. Leave the light on. Toggle the other switch to see if it turns the light on and off.
Is a good switch a bad switch?
If it does, it is a good switch and the other is bad. One of these switches will not turn the light on and off (while the light is on) and that is the bad switch. Once you identify the bad switch, follow the steps below to verify it is bad and needs to be replaced.
Do you have to remove the wires from a 3 way switch?
Remove the two 3-way switches so you can access the switch terminals. The wire connections do not have to be removed. Using a continuity tester, check continuity between the common (black) terminal and each of the traveler terminals (brass colored) of each 3-way switch.