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
Renovation 4th Edition Page 66