3-way Wiring

[Jake Chominsky]

I have an 1950’s home with older wiring. Most of the house only has a black and white wire connecting to lights and recepticals. I want to do a 3-way switch. Currently, the power is coming in through the light then connecting to the on/off switch. How could I install a 3-way if I can only add a new wired line from a new switch (#2) to the current light and also cannot upgrade or touch the existing wired line from the current switch to the current the current light? The reason I cannot touch the existing line is because it is behind 2x4s and walls where’d I have to demo a wall which is outside of my capabilities.

[Dean Hoffman]

Maybe some remote control three way light switches:

[Ed Pawlowski]

May not even need a 3-way depending on where and how it is used. Alexa, turn on first switch.

[micky]

What floor is the switch on? How many floors in the house? Finished ceiling in the basement? Finished floor in the attic?

You may or may not not need to demo anything to run another wire, but answer the 4 quewtions above.

[Ken]

Look at:

[gfretwell]

I would look at a wireless solution. There is no way to add a 3 way loop without running 3 wire plus ground cable.

[trader_4]

His case is the "light first" one. A three wire cable to the new location and two 3 way switches will do it. The only issue is code compliance, since there is no ground on the circuit. I guess you're either supposed to rewire the whole circuit or get an inspector that says it is ok to expand this without being compliant. It would be no less safe than what's already there.

[micky]

Jake, you haven't answered. Do you want to khow how you may be able to add your switch without demo, or not?

Ken's wiring diagrams are very good. The one that's best for you depends on the answer to the 4 questions above.

[Tommy Silvah]

A few strategically placed access holes in the walls and ceiling made with a 6" hole saw and even a hack like Sweener could knock this job out in less than a day.

[trader_4]

He only said it would be difficult to run a new cable where the existing cable run, not between the existing switch and the new proposed location and he implied that can be done. That's all he needs for it to work.

[micky]

Depending on where the switch and light are, it might not be necessary to put any holes in the walls.

If the floor above is an attic without a finished floor, you can likely drill from the existing switch box up to the attic, using a flexible 6' drill bit, which they nnow sell at home depot (probalby get the biggest diameter they sell) then run the cable to the light fixture which shoudl be available under the insulation. Then decide where the second switch will be, cut the hole for it, and drill up into the attic again.

If the floor below the light switch is a basement with an unfinished ceiling, you can likely drill down from the swtich box, through the plate into the basement, and run the cable over to where you want the switch to be. you will have already drilled down from the switch location to the basement and you can feed the cable up to the new switch location.

No damage to any wall or ceiling.