Tapping into a 3 way switch


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Old 06-05-23, 10:46 AM
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Tapping into a 3 way switch

I have a three way switch at top of basement stairs. The light is located at bottom of stair landing, along with two switches controlling light at each end of landing. I would like to add a light at top of stairs above the switch. Is it possible to tap into that switch to add a light directly above it?

Thank you in advance for help

 
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Old 06-05-23, 11:56 AM
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So you have two 3 way switches.... one on each level and one light at the lower level.
You want to connect a light to the upper level switch.

In that application.... it is possible but not likely.
Since the light is near the lower level switch.... that is typically the switch you'd need to connect to.
It's more common to connect additional lights to existing light.

Open the upstairs switch.
If there are only three wires and they are all on the switch... there would be no connection there.
 
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Old 06-05-23, 05:08 PM
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PJ, thank you. I will check the wiring at the upper switch. The house is early 70s. I would have thought code would have mandated a light within the stairwell. This has the light at the basement level.
 
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Old 06-06-23, 12:51 AM
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Is the basement stairway finished or open? Meaning what type of wall covering is on the stairway? If open and depending on the look of it meaning if it would be acceptable to you you would be able to tap off the light in the basement directly.

As PJMax said otherwise we need to know what the wiring is first before we can answer your question properly without guessing.

You can shut off the breaker to this basement stairway light setup. Do'nt just turn off the switches. Actually turn off the breaker. If you are not absolutely sure which breaker it is turn the light on by either of the two switch then flip breakers until the light goes out. Gently pull the switches out of the boxes (do not remove any wires!!) and take a few clear pictures of each switch so we can see the wires clearly. Also, on each of the switches will be one odd colored screw (discount, don't count the ground screws on the switches). On the three way switches 2 screws will be the same color and the third will be a darker color (usually). If all three screws happen to be the same color look on the backs of the switches. It would have a marking of "Common" imprinted on it. Make note on the diagram where the screw, which is called the common screw is located on each switch in your diagram. This is important.

Again, don't remove any screws yet attempting to do anything yourself.
 
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Old 06-06-23, 03:25 AM
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Three wires at switch. White, Back, Red. All attached to switch screws. Finished walls, so I will try to snake cable from a light in basement connected to this switch. Thanks again
 
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Old 06-06-23, 09:16 PM
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Three wires at switch. White, Back, Red. All attached to switch screws. Finished walls, so I will try to snake cable from a light in basement connected to this switch.
You need to know which switch to run the cable to. Also, may be best to run the new cable to the existing light instead. We can't tell you until you tell us what is at each switch, not just one.

If you have one 3 way switch with only 3 wires (not counting ground) you can't run the cable from that switch to your new light.

Am I missing something here?
 
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Old 06-07-23, 03:30 AM
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I am running cable from an existing light, not switch.
 
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Old 06-07-23, 07:50 AM
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If you are tapping from the light itself then you are good to go.
 
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Old 06-07-23, 03:52 PM
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Thanks again. Appreciate advice
 
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Old 06-08-23, 01:29 PM
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Normal wiring......

Three wires at switch. White, Back, Red. All attached to switch screws. Finished walls, so I will try to snake cable from a light in basement connected to this switch. Thanks again
This is telling us that the upstairs switch is a dead end three way switch and no connections can be made there for a light. Connecting to the existing light is the easiest way to extend the circuit.
 
 

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