Renovation 4th Edition

by Michael Litchfield

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