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jsirick
Two way switch

How do you wire a two way switch?

JLMCDANIEL
Re: Two way switch

Just guessing you mean a 3 way switch. All three way are wired as drawn, although path of wiring may be different. Power goes to the common terminal on one switch and the load (ex. light) is connected to the common on the other switch. The two traveler posts are connected to the two traveler posts on the other switch. Pleas not the location of the two traveler posts and the common post may not match the drawing. Check the markings on the switch or the documentation with the switch.

Jack

Timothy Miller
Re: Two way switch

Howdy 6 ways to wire a 3 way swith... Consider looking to a basic wiring book for diagrams and instructions at library or big box stores or buy one uses on the web...
I use the simpliest way to me on all or ours. Run a two wire from circuit to first switch 14/3 three wire from fist switch to second switch and two wire to the light.

JLMCDANIEL
Re: Two way switch

Tim,
Actually there is only one way to wire three-way switches, there are however multiple cable paths that can be used.
Jack

NEC
Re: Two way switch

More than one way. Legal as well.

JLMCDANIEL
Re: Two way switch

Well NEC, I stand corrected.:o There are 2 ways to legally wire 3-way switches. I, however, have never seen it done that way.
Jack

NEC
Re: Two way switch

Learned to wire 3-ways with a “California” 30+ years ago. Great if you did not have any three wire left or wanted a hot and neut at both switches. If you draw it out it will work with a two wire between the switches and a two wire from each switch to the light.

I have not wired a three way like this for 30 years and feel sorry for the guy that needs to troubleshoot a problem.

Even on our electrical site the issue came up and it took me a while to remember how we wired it.

There is another way to wire a three way that switches the neut. Not legal but works and I had this arrangement in a home with a detached garage.

JLMCDANIEL
Re: Two way switch

There's a way to switch hot an neutral also but it has been illegal since the 20's. http://i125.photobucket.com/albums/p66/JohnJ0906/carter.gif Not sure when switching neutral was made illigal.
Jack

Fencepost
Re: Two way switch
JLMCDANIEL wrote:

There's a way to switch hot an neutral also but it has been illegal since the 20's. http://i125.photobucket.com/albums/p66/JohnJ0906/carter.gif Not sure when switching neutral was made illigal.
Jack

The problem with switching the neutral is that you can have a situation where the light is off, but there is still a voltage potential relative to ground at the device (that's a fancy way of saying you'll get a zap if you stick your finger in the light socket). What makes the "Carter" setup described by JLMcDaniel even worse is that sometimes, the shell of the light socket is energized. In all modern wiring, the shell is not to be "energized" at any time but rather is to be continuously connected to a grounded neutral.

The advantage, of course, is that you can wire in an outlet at the location of the second switch without running extra wires.

JLMCDANIEL
Re: Two way switch
Fencepost wrote:

The problem with switching the neutral is that you can have a situation where the light is off, but there is still a voltage potential relative to ground at the device (that's a fancy way of saying you'll get a zap if you stick your finger in the light socket). What makes the "Carter" setup described by JLMcDaniel even worse is that sometimes, the shell of the light socket is energized. In all modern wiring, the shell is not to be "energized" at any time but rather is to be continuously connected to a grounded neutral.

The advantage, of course, is that you can wire in an outlet at the location of the second switch without running extra wires.

Switching neutral was pretty common in K&T wiring. What really makes the "Carter method" the most dangerous is the fact that if you have a switch failure or a make before break situation is that you are providing a direct short between hot and neutral at the switch. Sparks and fire danger.

We know why you don't switch neutral, the question is when was it made illegal?
Jack

Timothy Miller
Re: Two way switch
JLMCDANIEL wrote:

Tim,
Actually there is only one way to wire three-way switches, there are however multiple cable paths that can be used.
Jack

Thanks for the clarification.

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