An Electrical Question

Paul Graupp · Post by **Paul Graupp** » 15 Mar 2003 7:20 pm

In the Pennsylvania Dutch home of my youth, there was a switch at the first floor stairwell landing that would turn on the top of the stairs light if it was off. If it was already on then this 1st floor switch would turn the light off when toggled. The same was true of the upstairs switch.

I'm trying to figure out how they did that and I'm falling flat on my you know what. Any ideas or answers to this wiring set-up ??

Regards, Paul

Earl Foote · Post by **Earl Foote** » 15 Mar 2003 7:53 pm

Use two 3-way switches. Or go here: http://www.handymanwire.com/articles/3wayswitch.html

C Dixon · Post by **C Dixon** » 15 Mar 2003 9:09 pm

Earl is correct. Both switches in that example Paul, were "3 way switches". Home Depot sells them or any electrical supply house.

A 3 way switch is simply a single pole double throw switch.

They are wired as follows:

1. The hot eletrical circuit (usually black wire), is wired to the hot connector on the light socket.

2. The other light socket connector is connected to the common connector of one of the 3 way switches.

3. Then the two poles of both 3 switches are wired in parallel to each other.

4. Finally the common side of the other 3 way switch is wired to the common or cold side (usually white) of the electric supply.

This permits either switch to turn the light on or off regardless of the other switch's setting.

And it does not stop here. IF you need another switch, or any number of additional switches, you use a "4 way switch". These are wired BETWEEN one of the 3 way switches and the other 3 way switch in a continuous series manner.

IE, two of the poles on the 4 way connect to one of the 3 ways. The other two poles on the 4 way connect to the other 3 way. And this can continue indefinitely for as many switches as one wants.

Each switch can then turn the light on or off, regardless of the setting of any of the others switches. BUT ONLY 2-3 way switches are ever necessary. But one can add as many "4 ways" as needed.

carl

C Dixon · Post by **C Dixon** » 15 Mar 2003 9:11 pm

I apologize to both Earl and Paul. I did not see the URL link til after I had posted. The link is much clearer with pictures than my write up.

Sorry bout that,

carl

Joseph Barcus · Post by **Joseph Barcus** » 15 Mar 2003 9:49 pm

I always run one black wire from source or (power) to one switch the colored leg, then on the other switch run the black down from the light to the other colored leg, then on the other two run two reds back and forth from both switchs or blue never use white unless you tape it with black tape to keep anyone from mistaking it for a nutral, tie all your whites in at the light, but thats just my way is all, have a great day joe

C Dixon · Post by **C Dixon** » 16 Mar 2003 7:16 am

Joseph,

That WOULD work. But it would violate the NEC (National Electrical Code). Any honest building inspector who was well versed on electrical code would deny permit on the circuit if wired this way.

carl

Joey Ace · Post by **Joey Ace** » 16 Mar 2003 9:56 am

Violating Electrical Codes may cause an insurance inspector to tell you your Fire Insurance is void at the worst possible time.

In the interest of keeping this Forum focused on Steel and Musical Topics, I'm closing this.