Electrician in training


Old 01-14-06, 06:50 PM
Thread Starter
Join Date: Jan 2006
Location: New York
Posts: 5
3 way switching?

First off hello to all. I'm new to this sight.
I'm in a advanced training course which started on the 3rd of Jan. We've worked on a few different 3 way switch patterns. The two I have to do next week is :

1. Power coming in from the receptacle, which is hot at all times to 3 way S1 to S2 than to a light.

The other is

2. Power coming in from the receptacle, power half the receptacle at all times, the other half is powered by the 3 way switches.

The first senario I think I can get through but the second is killing me.

Any suggestions on how to better understand the breakdown of 3 way switches.

Any advise is greatly appreciated.

Last edited by Mr.Coax; 01-14-06 at 06:58 PM. Reason: changed title
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Old 01-14-06, 07:02 PM
Join Date: Sep 2003
Location: Central New York State
Posts: 13,973
Draw pictures on paper or on a white board. Use different colors for the various wires. Leave grounds off your drawings, since they all get connected and don't factor into how the circuit functions.
Old 01-14-06, 07:12 PM
Join Date: Sep 2000
Location: United States
Posts: 18,497
Of course you can find complete diagrams of all this stuff on the web, in various books, and in various pamphlets. But also of course, you don't want to do this or you'll lose the learning experience of figuring it out yourself.

The electrical aspects of all 3-way switch setups is identical. The continuously hot wire runs to the common screw on the first 3-way switch. That switch, depending on its position, directs that power to the first traveler or the second traveler (with the other traveler being dead). At the second 3-way switch, power comes in on either the first traveler, or the second traveler, as selected by the first 3-way switch. The second switch connects either the first traveler, or the second traveler, to the common screw (depending on switch position). A wire then connects this second common screw to the receptacle. The neutral from the power feed connects uninterrupted to the neutral to the receptacle.

If both switches select the same traveler, then power gets through to the receptacle. If both switches do not select the same traveler, then the power ends at the second 3-way switch.

So the description above is exactly identical in all five ways to wire this. The only difference among the setups is which boxes those wires pass through on the way to where they are going.

Let's take an example. We know from the above description that the continuously hot wire must go first to the first 3-way switch. So if the power cable comes first into the receptacle box, the continuously hot wire is so far in the wrong place. So it must pass through the box and continue on to the first switch box.

A half-switched receptacle should be thought of as two problems. First, figure out how you would wire the switched half. Then figure out how you would wire the unswitched half. Then just merge the two diagrams together, eliminating the redundant wires.
Old 01-17-06, 08:14 AM
supernix's Avatar
Join Date: Jan 2006
Location: Greenville, SC
Posts: 7
My dad showed that a long time ago. He had a receptacle and there was a tab between the top and bottom. Well he broke the tab and that seperated the circuit so you could have one live all the time and one switched.

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