whenever you splice solid wires
white wire with black electrician’s tape to indi-
with a wire connector, twist the
cate that it is serving as a hot wire to the back-fed
wires together and trim the end
5. Connect the switch. The NEC dictates that the white wire in
before you twist the connector
black lead to the
back-fed wiring is always the hot lead (power
into place. This guarantees a
hot wire.
coming in). The black wire, on the other hand, is
solid connection between the
Because dimmer
the switch leg that runs back to the fixture.
wires should the wire connector
bodies tend to be
larger than the
First, connect the ground wire to the green
come loose. ideal industries
singlepole
ground screw on the back-fed switch. Next, con-
makes screwdrivers that have a
switch they
wire nut driver socket in the han-
nect the switch-leg wire (black), then the hot wire
replace, make
dle, and this makes it easy to
(white taped black) to the switch terminals. To
sure beforehand
spin the connector on tightly.
keep looped wire ends snug against the screw
that the box is
shaft as you tighten down the screw, pull gently
big enough.
on wires, as shown. Not fumbling with wire ends
saves time.
306 Chapter 11
Finally, tuck the wires into the box, screw the
P r O t I P
switch to the box, and install the cover plate.
Wiring a linear slide dimmer. Newer, more
When cleaning touch-pad
sophisticated dimmers often require different
dimmers, wipe with only a clean,
connectors—wire leads rather than screw
soft rag, a damp sponge, or a
terminals—but they’re still basically switches
cleaner recommended by the
that interrupt only the hot wires. For standard
manufacturer. Touch pads are so
single-pole switches, it doesn’t matter which
sensitive that the wrong spray-
screw terminals you connect a switch leg or hot
on cleaner can make them go
wire to, but it does matter which wire you attach
haywire, causing lights to cycle
wildly up and down.
to dimmer leads.
Today’s dimmers are sophisticated and expen-
sive, so always read the manufacturer’s direc-
1.
tions. The slide dimmer shown in the photo
Before replacing any device, turn
off the power and use a voltage tester
sequence on p. 306 can be wired as a single-pole
to be sure. To test a switch, remove
or three-way switch, depending on which wires
the cover plate and carefully touch
you connect. It has a bare-wire ground, red and
the tester to terminals and wires.
black hot wires, and a yellow wire that is used to
Here, a voltage tester shows
wire the dimmer as a three-way device.
energized wires.
If the convertible device will be used as a
single-pole dimmer, you won’t need the yellow
wire. So cap it with a wire connector.
Splice the ground pigtail to the device’s bare
ground lead. Then splice the switch leg from the
4.
box to the red lead on the device. On devices with
Screw the replacement switch
(here, a dimmer) to the box.
wire leads, typically a red lead attaches to the
switch leg.
Finally, attach the incoming hot wire to the
other hot lead (black) on the device. Carefully
fold the wires into the box and push the dimmer
into the box. Screw the device to the box, and
install the cover plate.
2. When the tester indicates all
replacing a single-pole switch. You can
power is off, unscrew and pull the
replace an old single-pole toggle switch with a
switch from the box.
new one or with a convertible dimmer wired as
a single-pole dimmer. That is, you can use the
existing wires, but first turn off the power to the
circuit. Use a non-contact tester to see if voltage
5. Install the cover plate and
is present at the switch box. If the tester glows,
test the switch.
there’s power present: Turn it off at the fuse box
or breaker panel. Test again. When the power’s
S a f e t y a l e r t
off, unscrew the old switch and pull it out from
the box.
in some very old houses, you
Disconnect the switch wires and note their
may find that the neutral wires
condition. If the cable’s fiber sheathing is frayed
were attached to a switch—
but individual wire insulation is intact, the wires
rather than the hot wires, as
are probably safe to attach to the replacement
required by codes today. or, the
switch. If there’s debris present in the box, sweep
hot source conductor could
or vacuum it out.
3. Check for voltage again, then
reside in the fixture box with a
Connect the wires to the new switch. There
disconnect the old switch, and
switch loop down to the switch
may not be a ground wire to attach to the new
examine circuit wires for cracked
box. When working on old
switch’s ground screw, but code doesn’t require
insulation. If existing wires are in
switches or fixtures, test all wires
good shape, attach them to the
grounding a switch if there’s no ground wire
for voltage. even if you’ve flipped
new switch.
feeding the box. Once the dimmer’s connected,
a fixture switch off, there could
set it flush to the wall, and screw it to the box.
still be a hot conductor in the
fixture box.
Note: Any replacement switch must match the
type of fixture it controls, whether line voltage or
electrical Wiring
307
low voltage. Typically, the dimmer rating is
stamped on its face. In this case, the rating speci-
Cover all ConneCtIons fies, “For permanent incandescent fixtures.”
all electrical connections not end-
Finally, install the cover plate to protect the
ing at a switch, fixture, or receptacle
connections in the box and to prevent switch
users from inadvertently touching the wire ends
must be housed inside a covered
or dimmer terminals.
junction box so they can’t be dis-
turbed. electricians often use an
Installing a wireless switch. Traditionally, add-
existing light box as a junction box
ing a light fixture that could be controlled from
in which to splice a cable feeding a
several locations meant retrofitting three-way or
new fixture. When there’s not
four-way switches—which can turn into a
night-
mare. Fortunately, today’s electricians have
enough room in an existing box,
another, almost effortless option—installing wire-
use a separate junction box to
less switches.
house the splices.
Installing three-way wireless capability can be
as simple as replacing a mechanical switch (a
single-pole toggle, for example) with an electron-
ic master switch and locating a wireless controller
at some distant point. In the photo sequence on
this page and the facing page, we installed a
Lutron® Maestro Wireless® dimmer and a com-
panion Pico® Wireless control.
Start by turning off power to the existing
(mechanical) switch, and use a voltage tester to
be sure it’s off. Remove the switch cover plate. To
InSTAllInG A WIrElESS SWITCH
be doubly sure the power is off, apply the voltage
tester to the switch’s terminals and wires. Unscrew
the switch from the outlet box, then pull out the
switch and disconnect its wires.
Electronic switches are sensitive (and expen-
sive), so follow the manufacturer’s installation
instructions exactly. As most do, the Lutron elec-
tronic dimmer looks like a standard back-wired
switch, with a green grounding lead coming off
it. Attach the wires per instructions, screw the
device to the box, install the cover plate, turn the
power back on to the switch, and program the
Pico Wireless control via buttons on its face.
Mounting the wireless control—say, at the far
end of a hall—is as simple as sticking an adhe-
All you need to retrofit wireless switches. from left: a
1. Turn the power off, remove the
sive-backed mounting plate to a finish surface. If
wireless controller, a visor clip, wallmounting plate for
cover plate of an existing switch, and
you want a more permanent mounting, use the
the controller, and an electronic master switch.
test to be sure the power’s off.
screws provided—and expansion anchors if the
Disconnect the old switch.
wall is drywall. The wireless control slips into the
mounting plate and is in turn covered by a snap-
on plate. The controller needs no wires because
it has a tiny battery that’s typically good for
10 years. It needs only enough power to “talk”
2. Electronic switches are expensive,
to the master switch.
so read installation directions
Even modest wireless devices have a lot of
carefully. Here, existing hot and
useful functionality. The Pico control also can be
switchleg wires are attached to the
clipped to a car visor so that as you approach
terminals of an electronic dimmer
home, you can turn on the porch light. Inside the
that serves as a master switch. The
house, you can program lights to turn off and on.
green switch lead is connected to a
bare copper ground.
In a baby’s room, for example, you could pro-
gram a light to dim slowly over a 10-minute peri-
od so the baby isn’t startled by sudden darkness
as he or she drifts off to sleep.
308 Chapter 11
Fixture Wiring
The right lighting fixture can transform a room;
it could also cut your energy bills big-time. In
this brief section, you’ll get an overview of
mounting devices, see how to install the most
space-conserving fixture—recessed lighting—and
learn how to transform an existing incandescent
light fixture into one with a more efficient light-
emitting diode (LED) light source, thereby reduc-
ing energy usage by up to 75%.
MounTing fixTures To boxes
As shown on pp. 282 and 290, there are many
mounting options for boxes. The main choice is
3. Tuck in wires, screw the electronic switch to 4. Down the hall, a small mounting plate is
whether you nail or screw the box directly to a
the box, then install the cover plate. After
screwed to or stuck on the wall. The controller
stud or ceiling joist or use an extendable mount-
testing the switch, program the wireless
slides into the plate. no cutting, drilling, or
ing bar to which the box is attached. Either
controller. The controller will talk to the
wirefishing required! Cover plates will make it
method works fine, but a box that slides along a
dimmer, telling it to raise or lower the lights—
look like any other switch.
mounting bar means you can more easily posi-
in effect, it is a threeway switch.
tion the light fixture just where you want it.
If mounting screws on all light fixtures were
exactly the same diameter and spacing as the
screw holes on all boxes, life would be simple
Ceiling FIxture eleMents
and you’d screw the fixture directly to the box.
But there are many different box sizes and con-
In this basic setup, the ceiling box mounts to an adjustable bar, which is screwed
figurations, and light fixtures vary considerably.
to ceiling joists. the bracket is attached to the box and the fixture is screwed to the
Consequently, there are many mounting brackets
mounting bracket. all metal boxes and brackets must be grounded to be safe.
(see p. 310) to reconcile these differences.
many electricians use grounding screws in both the box and the bracket, but one ground
Always examine existing outlet boxes before
is sufficient. the metal mounting screws provide grounding continuity to box and
buying new fixtures, and make sure that fixture
bracket. If the fixture has a ground wire, it must be attached to either the ground wire
hardware can be mounted. Otherwise, a routine
in the box or to the grounding screw on the mounting bracket. the ground wire in the
installation could turn into a long, drawn-out
box must be long enough to attach to the ground screw in the box, and extend out the
affair with a lot of trips to the hardware store.
box for attaching to the fixture ground wire.
Here’s an overview of how various fixtures
mount to outlet boxes. All metal brackets, boxes,
and lamp fixtures must be grounded to be safe.
Ceiling fixture elements
There are special grounding screws (10-32
machine screws, colored green) that ensure a
zzzzzz
Supply cable
positive connection to metal boxes or plates
Adjustable bar
Bare copper
when installed in a threaded hole. Do not use a
ground wire
wood screw or the like to attach the ground wire
to the box; it doesn’t provide a good enough
connection.
Grounding
screw
Flat-mounting brackets. Typically, a mounting
Ceiling box
Neutral
bracket is screwed to a fixture box, and the fix-
supply wire
Hot supply wire
ture is at
tached to the bracket, either by machine
screws or, as is more common for chandeliers, by
Wire nut
Mounting bracket
a threaded post that screws into a threaded hole
Grounding screw
in the center of the mounting bracket. Brackets
Bracket mounting screw
can be as simple as a flat bar with screw slots,
Neutral
Hot
but some adjust by sliding, whereas others are
fixture lead
fixture lead
offset slightly to provide a little more room for
Fixture base
Globe-style bulb
electrical connections—and fingers. Ring brack-
ets can be rotated so the slots line up perfectly
with outlet-box and fixture screw holes.
electrical Wiring
309
3⁄8-in. bar
trombone bar
(sliding,
adjustable)
european hanger (sconce
hangs on it rather than being
screwed to it)
pivoting
offset bar
1
1⁄
⁄8-in. bar
2-in. bar
1⁄2-in.
offset bar
ring plate
Mounting brackets
no brackets. Some fixtures, such as the recessed
lighting fixture shown on pp. 311–312, don’t
require a mounting bracket. The fixture has its
own junction box; once inserted into a hole cut in
the ceiling, the fixture is supported by the ceiling.
Integral clips and trim pieces pull the fixture
recessed CeIlInG FIxtures tightly to the plaster or drywall ceiling. Recessed
cans can be IC-rated (they may be covered with
recessed light fixtures vary. the low-voltage model in the photo sequence on
insulation) or may be non-IC-rated (cannot be
pp. 311–312 has a transformer at the end of its assembly to reduce line voltage.
covered with insulation).
this drawing shows a model that runs on line voltage (120v), so it has no transformer.
If the unit is watertight, it will have additional trim or lens elements. Closely follow
reTrofiTTing reCessed lighTing
the installation instructions provided with your fixture.
As the name implies, recessed lighting fixtures fit
into the space above the ceiling. Recessed fix-
tures create a strong cone of light and are fre-
recessed light fixture
quently used to illuminate work areas or tight
spaces. If desired, installing recessed fixtures
zzzzzz
Supply cable
spaced closely together (half the ceiling height a
Frame or armature
6-in. can with standard baffle trim) will create
Renovation 4th Edition Page 72