How to Replace a 3 Way Switch and the dangers of not calling an Electrical Professional

How to Replace a 3 Way Switch and the dangersFigure 3.
of not calling an Electrical Professional
As a Licensed Electrical Contractor I find the mostFigure 4.
common calls I receive from
“Do-It-Yourselfer’s” is about changingStep 1
a switch or receptacle. I hope by reading thisThe first and most important step is to turn off
article I can shed some light on your task at hand.the circuit that you will be working on. Find the
Since it can be quite confusing even for someright breaker in the breaker box and flip it to the
electricians, I am going to some detail on the 3"Off" position. If you have a fuse box, find the
way switch topic. Please read through theright fuse and remove it completely from the
complete article to get a good grasp of the howpanel. You can verify that the correct circuit has
a 3 way switch is wired.been turned off if the light controlled by the
switch no longer works.
Here are a couple scenarios of the main calls I getStep 2
from my customers….The next step is to remove the cover and switch
“I replaced my 3 way switches and now thefrom the box.
bedroom lights turn off when I flip theStep 3
switch”. There are a few reasons for this. ButVerify there is no power in the box. This can be
the most common reason is.done with a tic tester available at Lowes or Home
When the homeowner disconnected the switchDepot.
they took splices apart in the box and when theyStep 4
reconnected them they were not in the properThis is the step that can cause you a big
configuration. This can be quite dangerous andheadache so follow it carefully. Before you
expensive. In one case the homeowner had hisdisconnect the switch determine which wire is
brand new plasma TV and Stereo systemconnected to the common terminal on the 3 way
totally… “Fried” When he reconnectedswitch. (The common terminal is usually copper or
his splices he hooked up 220 volts to that outlet.brown). Mark this wire with tape. Now disconnect
“I replaced my 3 way switches for my hall.the two traveler wires. The screws they are
Now when I turn the light off at one end of theunder are the same color. (Usually silver or brass)
hall, I can’t turn it back on from theYou might also have a ground wire connected to
other”.your switch. (Usually a green or bare copper wire)
This is usually a simple fix. There is a pair of wiresIf there is a ground disconnect it now. If
called “travelers” and in this situation theyeverything is correct you should have now have
are usually reversed with the common wire.3 or 4 wires hanging out of the box.
I also receive numerous calls about this fromStep 5
general contractors, handymen, maintenanceTake your new 3 way switch and locate the
personal, etc…common screw. Now take the wire that you
Now before we go any further with this article. Imarked with tape and connect to this screw. The
want you to understand that I am not writing thisnext step is to connect your two traveler wires
article to teach you how to repair or replace a 3to the other two screws. It does not matter
way switch or 3 way systems. I am writing towhich wire goes to which screw as long as there
try and make the point that this is one of thoseis only one wire under the screw. If you have a
situations where you can end up in some real hotground wire you should now connect it to the
water, and you should call a service professional ifgreen screw.
you do not have the proper electrical knowledge.Step 6
There are many ways to wire a 3 way system. ITo be safe you can wrap tape around the switch.
am going to show you 3 configurations of a 3Make sure you cover the screws so they
way system.don’t short to the box. Put the switch and
Do not confuse this with a 4 way system!!! (Athe plate back in the box. At this point you can
system with 3 or more switches)turn on the power.
The First thing you need to know. A 3 wayStep 6
system only has 2 switches. If you have anyHere is a simple test to make sure that your 3
more or less you are not looking at a 3 wayway system is operating properly.
system.**Please Remember to be careful and read all
Figure 1 (Example 3 way switch)installation instructions supplied with materials when
tackling your project.
Figure 2Please find a professional to install or help with
your project if you are unsure of your abilities.