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Saturday, December 12, 2009

How to test a three way switch

If your going to test a switch your going to need one thing. A meter, now you don't need an expensive meter just something that shows current. Something that looks like the one on the top right of this page.

How to test a switch

If you have any questions please ask in the comment link below, I will answer them to the best of my ability, also if you have future projects that you would like step by step instructions please post in the comment box I will usually answer the same day.

1) Tools.
a) AC meter
b) Phillip head screw driver
c) skinny flat head screw driver

2) Remove the plate cover from the switch. This will be the easiest part of your project. On the top and bottom of the switch there will be small screws. You will need the thin flat head screwdriver to remove these. If the location you are installing the switch has multiple switches you will need to remove all the plate screws. Then remove the plate and place the screws and the plate together for replacing later. Do not lose those little screws believe me they are easy to lose.

3) Remove the switches. OK the fun part. Take a drill or a Phillips head screw driver and take out the screws on the top and bottom of the switches. Now grab the yoke of the switch (that's the top and bottom of the switch) do not grab the switch by the side we want to test the switches and the only way to do this is to pull out the switches. The power is located on the side so if you grab it by the sides you will get shocked. This is electricity SAFETY FIRST!!!!! So grab the yoke and pull out the switches.


4) Testing a 3 way switch. A three way switch has three screws.
a) Start with your switch in the down position
b) Set your meter to AC. There may be multiple voltages to set to on the meter, you just need to put it at a voltage higher than what you are working on. So if you are working on a light or receptacle (120v) it will probably be 200.
c) Put one of the leads of the meter on the metal box, if you don't have a metal box you will have some bare copper wires in the box, put it there. Take the other lead and put it on the black screw. What we are looking for is for the black screw to have power when the switch is in one position and not when it is in the other so flip the switch up and down. If your black screw always has power skip to (h). If your black screw has power then does not have power, depending on the position of the switch, so far so good.
d) There are two gold screws on the switch, one has power right now, find it and keep note which screw it is.
e)Now flip the other switch that controls the same light (if you have a switch with three screws and three wires on it, there is more than one switch controlling your outlet) and come back to the switch we are working on and test the other gold screw, you should have power there now. If you do not get power in the other screw your problem is in the other switch and skip to (e)
f) If before, your black screw had power in the up position it will now have power in the down position. So test your black screw again, up and down, power no power. If your switch follows these rules your switch is fine and you need to test the other switch.
g)Test the black screw on this other switch and make sure you always have power on the black screw whether the switch is in the up or down position.
h) If your reading this I'm sure your getting confused but don't worry I am not explaining how it works, just how to test it so take your time and go step by step. You are at the power side of the three way switch. We are going to test the other two screws. Put one lead on the box or ground wires and the other lead on one of the gold screws. You should have power on this screw when the switch is in one position and not have power when the switch is in the other position. Test the other gold screw the same way, if your switch does not work this way, you have a bad switch, if it does go back to (d) and test the other switch. If you already tested the other switch the problem is not in the switches.
If you found this helpful please click on one of the ads at the top or bottom of the page for support.

John

Check your state and local codes before starting any project. Follow all safety precautions. Every effort has been made to ensure accuracy and safety. I can not be held responsible for damages or injuries resulting from the use of the information in this document.

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