Connecting A Dimmer
A dimmer switch is connected
between an incoming line and an outgoing line that runs to a
Bruce W. Maki,
||This dimmer switch has two wires to connect to
the "hot" and "switched" wires.
|After I had installed the old work box I
prepared the cables by stripping away the jacket.
||In this case the ground wires were tied together
with wire nuts, and the two neutral wires were connected with
|The grounds and neutrals were tucked away in the
back of the box.
One black wire is "hot-at-all-time" and the other is
"switched". It does not really matter which wire connects to
which terminal of the switch (unless the instructions say
||I wrapped the flexible stranded wire of the
switch around the stripped end of the hot wire, and installed a
|With both hot wires connected, the switch is
ready to install.
||I drove in the screws with a drill-driver, being
careful not to over-tighten them.
|I installed the cover plate and tested the new
Notes About Switch Wiring:
There are two basic ways that switches are connected in home
wiring. The first method is shown here, where a "feed" line comes
into the switch box, the neutral passes through, and the hot is
I call the second method "Remote Switch", for lack of a
better name. In this scheme, there is a "hot-at-all-times" cable at
the light's junction box, and a single two-conductor cable goes to
the switch. Technically, both the black and white wires to the
switch are hot (and in this scheme the white wire is supposed to be
marked as hot by wrapping the ends in black electrical tape).
Imagine the hot wire that feeds the light on the ceiling... and just
before the wire reaches the light, it is re-routed down to a box on
the wall where it connects to one side of a switch. When the switch
is closed, the current continues along the
other wire in the 2-conductor cable and reaches the light
bulb. It's as if the hot wire has been s-t-r-e-t-c-h-e-d all the way
down to a remote location... a switch on the wall.
So if you find a light switch with just one cable in the
box... it must be this "remote switch" method of wiring. Also,
note that with this scheme there will be live wires in the
junction box for the light, regardless of the position of the light
And if you find a light fixture with only one cable in the
box, it must be the first scheme. In this case turning off the
switch will definitely turn off the power to the light's junction
box (but check for power anyway, just for fun).
Back To Top
- Cordless Drill/Driver
- Flat Blade Screwdriver
- Needle-nose Pliers
- Wire Strippers
- Dimmer Switch
- Wire Nuts
- Cover Plate