Renovation 4th Edition

by Michael Litchfield

  easily through several studs or wall plates.

  278 Chapter 11

  Fish tape

  screwdriver set

  lineman’s pliers

  Cordless screwdriver

  utility knife

  analyzer

  needle-nose pliers

  Diagonal cutters

  non-contact

  voltage tester

  Combination wire

  Wire stripper/cutter

  offset screwdrivers

  stripper/crimper

  Cable ripper

  reciprocating saw. A reciprocating saw with a

  however, swear by a pulling grip, also called a

  P r O t I P

  demolition sawblade (see p. 48) is indispensable

  swivel kellum (see p. 293).

  for most remodeling jobs because it can handle

  In most cases, however, it’s simplest to use a

  Cordless drills and screwdrivers

  the occasional nail without destroying the blade.

  flex bit (flexible bit) to drill through the framing.

  reduce the tedium of screwing

  You can use a recip saw to cut openings in plaster,

  When the bit emerges, a helper can attach the

  wires to terminals, attaching

  but an oscillating tool with a Universal E-cut blade new cable to a small “fish hole” near the bit’s

  devices to boxes, putting on

  will cut plaster in a more controlled manner.

  point. Then, using a swivel kellum to keep the

  cover plates, and connecting

  new cable from getting twisted, put the drill in

  Cordless power tools. Cordless drills and saws

  myriad other items. if your

  reverse and pull the bit (and cable) back through

  enable you to keep working when the power is off

  screwdriver has a torque clutch,

  the holes it drilled. No fish tape required.

  or not yet connected. They don’t need an exten-

  use the lower settings (or a light

  A 48-in. drill extension will increase the effec-

  touch on the trigger) to keep

  sion cord and so are much more convenient in

  tive drilling length of a flex bit. Use an insulated

  from overtightening or stripping

  places with limited access.

  steering guide to keep the flex bit from bowing

  screws. always tighten cable

  Gone fishin’. Spring-steel fish tapes or fiberglass excessively.

  clamps by hand to avoid over-

  fish rods are used to run cable behind finish sur-

  tightening them and damaging

  faces. A fish tape is invoked in almost every old

  oTher useful Tools

  the incoming cable(s).

  wiring how-to book on the market. Today’s pros,

  No two electrician’s tool belts look the same, but

  most contain a tape measure, flashlight, small

  level, hammer, Speed Square, and a large felt-

  tipped marker. In the course of a wiring job, you

  may need several sizes of slot-head and Phillips-

  head screwdrivers, plus an offset screwdriver and

  a nut driver.

  If you’re wiring a whole house, rent a wire

  reel, a rotating dispenser (see p. 280) that enables

  you to pull cable easily to distant points. Reels

  hold 250 ft. of cable.

  Adequate lighting is essential to both job safe-

  ty and accuracy. If a site is too dark to see what

  color wires you’re working with, your chances of

  making a wrong connection increase. LED head-

  remodel wiring tools. from right: drywall saw (sometimes lamps are fantastic tools.

  called a stab saw), flex bit, bit extension, flex bit steering

  Sturdy stepladders are a must. In the electri-

  guide, and reel of fishing tape.

  cal industry, only fiberglass stepladders are

  electrical Wiring

  279

  Occupational Safety and Health Administration

  (OSHA)-compliant because they’re nonconduc-

  tive. Wood ladders are usually nonconductive

  when dry, but if they get rained on, wood ladders

  can conduct electricity.

  Choosing eleCTriCal boxes

  There is a huge selection of electrical boxes, vary-

  ing by size, shape, mounting device, and compo-

  P r O t I P

  sition. One of the first distinctions to note is that

  of new work boxes and remodel or cut-in boxes.

  Many electricians prefer to

  New work boxes are designed to be attached

  use screw-on boxes rather than

  to exposed framing, as is often the case in new

  nail-on types because screws

  allow them to reposition boxes

  construction and sometimes in renovations

  easily.

  where walls and ceilings are gutted. Cut-in boxes

  are designed for attachment to existing finish

  surfaces—which frequently involves cutting into

  plaster or drywall.

  But of all the variables to consider when

  choosing boxes, size (capacity) usually trumps

  the others. Correctly sized boxes are required by

  code and make your job easier because you don’t

  have to struggle to fit wires and devices into a

  space that’s too small.

  box capacity. The most common box type is a

  single-gang box. A single-gang box 31⁄2 in. deep

  A wire reel prevents kinks in cable as you pull it.

  has a capacity of roughly 221⁄2 cu. in., enough

  space for a single device (receptacle or switch),

  three 12–2 w/ground cables, and two wire con-

  nectors. Double-gang boxes hold two devices;

  triple-gang boxes hold three devices. Remember:

  box fill Worksheet* Everything that takes up space in a box must fit

  without cramping—devices, cable wires, wire

  Item

  sIze (cu. in.)

  numBer

  total

  connectors, and cable clamps—so follow NEC

  recommendations for the maximum number of

  

  #14 conductors exiting box

  2.00

  conductors per box.

  

  #12 conductors exiting box

  2.25

  You can get the capacity you need in a num-

  ber of ways. Some pros install shallow 4-squares

  

  #10 conductors exiting box

  2.50

  (4 in. by 4 in. by 11⁄2 in. deep) because they’re ver-

  

  #8 conductors exiting box

  3.0

  satile and roomy. Because of their shallow depth,

  these boxes can be installed back to back in a

  

  #6 conductors exiting box

  5.0

  standard 2x4 wall. This allows you to keep even

  back-to-back switch boxes at the same height

  largest grounding conductor;

  

  count only one

  1

  from one room to the next. Shallow pancake

  boxes (4 in. dia. by 1⁄2 in. deep) are commonly

  devices; for each device, two

  used to flush-mount light fixtures.

  times the largest connected

  conductor size

  When you’re installing GFCI receptacles or

  

  need more room for connectors and devices, use

  internal clamps; one for all

  a 4S deep box. Finally, cover 4-squa
re boxes with

  clamps based on largest wire

  a mud-ring cover.

  

  present

  1

  Metal versus plastic boxes. Metal boxes are

  fixture fittings; one of each type

  sturdy and are available in more sizes than are

  

  based on largest wire

  plastic boxes. Some metal boxes can be inter-

  * Table based on NEC 370-16(b) and adapted with permission from Redwood Kardon,

  locked for larger capacity. Also, metal boxes are

  Douglas Hansen, and Mike Casey, Code Check® electrical (The Taunton Press).

  usually favored for mounting ceiling fixtures

  because steel is stronger than plastic. If code

  requires steel conduit, armored cable (BX), or

  280 Chapter 11

  Single­gang boxes come in three

  sizes: 18 cu. in., 20.4 cu. in., and

  22.5 cu. in. In general, bigger is better.

  new work boxes. Top row, from left: single­gang plastic, double­gang plastic, and triple­gang plastic.

  Bottom row, from left: single­gang face­nailing adjustable with (orange) snap­on data ring, double­gang

  face­nailing adjustable, and single­gang metal.

  MC cable, you must use steel boxes. All metal

  boxes must be grounded.

  getting box

  For most other installations, plastic is king.

  edGes Flush

  (Plastic boxes may be polyvinyl chloride [PVC],

  use an add-a-depth ring (“goof ring”) to make

  fiberglass, or thermoset.) Electricians use far

  box edges flush when an outlet box is more than

  more plastic boxes because they are less expen-

  1⁄4 in. below the surface—a common situation

  sive. Also, because they are nonconductive,

  when remodelers drywall over an existing wall

  they’re quicker to install because they don’t need

  that’s in bad shape. plastic goof rings, being

  to be grounded. However, even if a box doesn’t

  Throw a single­ or double­gang mud

  nonconductive, are best. Do not use a steel ring

  need to be grounded, all electrical devices inside

  (plaster) ring on a 4­in. box and it’s

  with a plastic box.

  hard to overfill.

  must be grounded by a ground wire that doesn’t

  depend on a device for continuity. Box volumes

  are stamped on the outside of plastic boxes.

  Cut-in boxes. The renovator’s mainstay is the

  2

  cut-in box (remodel box) because it mounts

  directly to finish surfaces. These boxes are indis-

  1

  pensable when you want to add a device but

  6

  don’t want to destroy a large section of a ceiling

  or wall to attach the box to the framing. Most

  cut-in boxes have metal or plastic flanges that

  3

  keep them from falling into the wall cavity.

  Where they vary is with the tabs or mechanisms

  that hold them snugly to the back side of the

  wall: They could be screw-adjustable ears, metal-

  5

  spring ears, swivel ears, or bendable metal tabs

  (Grip-Lok® is one brand).

  Mounting devices. The type of mounting brack-

  et, bar, or tab you use depends on whether you’re

  4

  mounting a box to finish surfaces or structural

  members. When you’re attaching a box to an

  exposed stud or joist, you’re engaged in new

  work, even if the house is old. New-work boxes

  Cut­in (remodel) boxes and accessories: 1. Single­gang box with Grip­lok tab (AKA Madison strap

  or cut­in strap); 2. Single­gang box with swivel ears; 3. Goof ring (used when a box is set too

  are usually side-nailed or face-nailed through a

  deep); 4. round ceiling box with metal spring ears; 5. Double­gang box with swivel ears; 6. Single­

  bracket; nail-on boxes have integral nail holders.

  gang box with adjustable ears. Box 1 should only be used for switches.

  electrical Wiring

  281

  The screw on the side of an adjustable

  box enables you to raise or lower the

  face of the box so it’s flush with the

  finish wall.

  The mounting bracket for adjustable boxes is

  Adjustable mounting bars (AKA bar hangers). from

  particularly ingenious. Once attached to framing, top: heavyweight bar for new work, where framing is

  the box depth can be screw-adjusted until it’s

  accessible; heavyweight fan­rated remodel bar, which

  flush to the finish surface.

  P r O t I P

  can fit through an opening and be expanded in place;

  Adjustable bar hangers enable you to mount

  and light new work bar for a light fixture.

  boxes between joists and studs; typically, hangers

  Most bar and ceiling box

  adjust from 14 in. to 22 in. Boxes mount to hang-

  assemblies are rated for 50 lb.;

  indicate the gauge and the number of the individ-

  ers via threaded posts or, more simply, by being

  the box should be marked inside

  ual wires inside.

  screwed to the hangers. Bar hangers vary in

  with a weight rating. if your light

  Typically, Romex cable has two insulated

  fixture weighs more than the

  thickness and strength, with heavier strap types

  wires inside and a ground—which may be insu-

  weight rating of a standard ceil-

  (rated for ceiling fans) required to support ceiling

  lated or, more often, bare wire. Thus, the Romex

  ing box, or if you’re installing

  fans and heavier fixtures.

  used for a standard 15-amp lights-and-outlets

  any ceiling fan, install a fan-

  circuit will be stamped 14/2 w/grd. For a 20-amp

  rated box instead.

  Cable and ConduiT

  circuit, 12/2 w/grd is required. Three-way switches

  Most modern house wiring is plastic-sheathed

  are wired with 14/3 or 12/3 cable, which has an

  cable (Romex is one brand), but you may find

  additional insulated wire. Again, wire gauge is

  any—or all—of the wiring types described here in rated for the load it can carry, so although you

  older houses. Inside cables or conduits are indi-

  can wire 15-amp circuits with 12-gauge wire,

  vidual wires, or conductors, that vary in thick-

  you can’t use 14-gauge wire anywhere in 20-amp

  ness (gauge) according to the load (amps) they

  circuits.

  carry. More about that in a bit.

  Metal-clad (MC) cable or armored cable (aC)

  nonmetallic sheathed cable (nM or romex)

  is often specified where wiring is exposed and

  is by far the most common type of cable. Covered could be damaged. Some codes still allow

  with a flexible thermoplastic sheathing, Romex is armored cable, the older of the metallic cables,

  easy to route, cut, and attach. Cable designations but that’s increasingly rare. In AC cable, the

  printed on the sheathing and the sheathing color

  metal covering of the cable acts as the ground; in

  reading a Cable

  Electrical cable. from top: type­nM (romex), type­Uf

  Cables provide a lot of information in the abbreviations stamped into the sheath-
<
br />   (underground), armor clad (AC), and metal clad (MC).

  ing. For example, NM indicates nonmetallic sheathing, and UF indicates underground

  feeder, which can be buried. the size and number of individual conductors inside a

  cable are also noted: 12/2 w/grd or 12-2 W/G, for example, indicates two insulated

  12aWg wires plus a ground wire. Cable stamped 14/3 W/G has three 14aWg wires

  plus a ground wire. (the higher the number, the smaller the wire diameter.) the

  maximum voltage, as in 600V, may also be indicated.

  Individual wires within cable have codes, too. T (thermoplastic) wire is intended

  for dry, indoor use, and W means wet; thus TW wire can be used in dry and wet loca-

  tions. H stands for heat resistant. N, for nylon jacketed, indicates a tough wire that can be drawn through conduit without being damaged.

  Finally, make sure the cable is marked NM-B. Cable without the final “-B” has an

  old-style insulation that is not as heat resistant as nm-B cable.

  282 Chapter 11

  MC cable, there is a separate insulated green wire

  P r O t I P

  that serves as a ground. To strip either type of

  metal cable, use a Roto-Split® cable stripper; it’s

  all cut-in boxes, whether

  vastly superior to the old method of using a hack-

  plastic or metal, must contain

  saw and diagonal cutters.

  cable clamps inside that fasten

  Conduit may be specified to protect exposed wir-

  cables securely. This is especially

  ing indoors or outdoors. It is commonly thin-wall

  important because it’s impossi-

  steel (electrical metallic tubing, or EMT), or PVC

  ble to staple cable to studs and

  plastic. Metal conduit serves as its own ground.

  joists when they are covered by

  Apart from service entrances, conduit is seldom

  finish surfaces. you need clamps

  to keep the cables from getting

  used in home wiring. When connected with

  tugged or chafed.

  weathertight fittings, conduit can be installed

  romex cable connectors. from bottom to top: plastic

  outdoors—and PVC conduit, even underground.

  push­in connector, two­cable hit­lock connector, 3⁄8­in.

  nM clamp with locknut, and metal box with internal

  Clamps. Every wiring system—whether non-

  clamps. Cable connectors are set in box knockouts to

  metallic, MC, AC, or conduit—has clamps (con-

  prevent wires’ insulation from wearing against sharp

  nectors) specific to that system. Clamps solidly

  edges and to protect electrical connections in the box