NOVEMBER 2019 PCWorld 107socket your light bulb is
screwed into, turning it
on. In the other position, it
will stop electricity from
flowing to that socket,
turning the bulb off. A
dimmer switch can also
vary the amount of
electricity flowing to the
socket, so that you can
brighten or dim the light bulb as well as turn
it on or off.
If you want to change the color of your
lighting, you’ll need a smart bulb, not a
smart switch. Unfortunately, smart dimmer
switches and smart bulbs typically don’t
work together. That’s because smart bulbs
are equipped with radios that depend on a
steady supply of electricity to operate, and a
dimmer varies the amount of electricity
flowing to the bulb.
DO YOU NEED A SINGLE
POLE SWITCH OR 3-WAY?
Next, you’ll need to determine if you need a
single-pole or a three-way switch. If only one
switch controls the flow of electricity to that
bulb you want to control, you have a single-
pole switch. If two switches can control
it—for example, switches on opposite sides
of the room—you have a three-way switch (if
more than two switches control the same
light, it’s described as a four-way circuit.)
If you’re replacing a dumb switch on a
three- or four-way circuit, you’ll typically
need to replace the other switch or switches
on that circuit with companion switches from
the same company that made the smart
swtich you’re installing. (The latest Wemo
WiFi Smart Light Switch 3-Way [go.pcworld.
com/wemo] is an exception to that rule, and
it can also be used in a single-pole
installation. It cannot, however, dim a light.)
In this how-to, we’ll replace a single-pole
switch with a C by GE Start Smart Switch
Motion Sensing+Dimmer (go.pcworld.com/
cstt), but the process isn’t radically different
for a multi-way circuit. (And if you don’t need
all the features this dimmer offers, GE
Lighting offers four simpler and less-
expensive alternatives [go.pcworld.com/
geli].) The first step—and the most
important—is to identify which circuit
breaker controls the electricity flowing to
that switch and to turn it off.
The next step is to remove the cover
plate so you can access the switch itself.
Waving a non-contact voltage tester insideSingle-pole switches are the easiest to replace, since only one switch
controls the circuit. In a three- or four-way circuit, more than one switch
can turn the bulb on and off.