Overview: Top ten tips for wiring new switches and outlets
Whether you're replacing
an existing switch or
outlet or wiring a new one, here are
10 great tips to help you make sure
your installation is safe and long
lasting. These tips go beyond the
basics, so if you're unsure how to
begin wiring a switch or an
outlet, check out these articles on electrical wiring.
Before you begin any electrical
work, always switch off the circuit
breaker in the main panel, and then
double-check that you've turned off
the correct breaker by testing all
the wires in the box with a non-contact
Tip 1: Use 4 key tools for safe and fast wiring of outlets and switches
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Four key wiring tools
Buy a voltage tester, a wire stripper, a noncontact voltage sniffer and a GFCI and outlet tester for wiring switches and outlets.
Here are four must-have tools if you plan to wire many switches and outlets:
Voltage tester. You can pick one up for a few bucks and use it to test for hot wires or to
find a neutral. Just touch the probes between a hot and a neutral, or between two hot
wires. The tester will light up if the wires are “hot.” The tester shown also tests for 240
Combination sheath and wire stripper. This Klein K1412 (about $23 at home centers and hardware
stores) is our favorite. In addition to slots for stripping insulation from 14- and
12-gauge wire, it has slots to strip the sheathing from 14- and 12-gauge nonmetallic cable.
Voltage “sniffer.” The beauty of this tool is that you don't have to touch bare wires to see
if they're hot. Just hold it near any wire or cable to see if it's
energized. We recommend using a noncontact
voltage tester like this to double-check
that all wires in a box
are “dead” after turning off
the circuit breaker. Prices range
from about $10 to $22.
GFCI receptacle tester. Just plug
it into any GFCI outlet and the
lights will indicate whether the
outlet is properly wired. Plug it
into a GFCI receptacle and press
the test button to see if the GFCI
is working correctly ($8 to $10).
Tip 2: Tighten loose outlets and switches
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Coil a wire
Wrap a scrap of 14- or 12-gauge wire into a coil.
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Install the coil
Slide the coil onto the mounting screw behind the “ears” and drive the screw into the wall box.
In a perfect world, switch
and outlet boxes would be
flush to the wall surface,
but it's not unusual to find
them slightly recessed.
Switches and outlets
mounted to recessed boxes
can get wobbly if you rely
on device “ears” for
To prevent this, slip a
coiled-wire shim over the
device's mounting screw.
The photo above shows
how to make a coil from a
scrap of insulated wire.
Hold the coil against the
box to gauge where to cut it
to span the gap between
the box and the surface of
the wall. Slip the coil over
the screw and tighten the
Your shimmed outlet will be
solid and secure.
Tip 3: Use pigtails on outlets
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Connect the outlet to pigtails rather than using the terminals for through wiring to other outlets.
Outlets have pairs of screws on each side that you
can use to connect downstream outlets, but it's best
not to use them. There are two reasons for this. First,
connecting the wires leading to downstream outlets
with wire connectors creates a more secure connection.
And second, it's easier to press the outlet back
into the box if fewer of its screws are connected to
wires. Instead, use wire connectors to connect the
neutral, hot and ground wires along with 6-in.-long
“pigtails.” Then connect the pigtails to the outlet.
Tip 4: Smart switches may need a neutral wire
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No neutral wire
Some switch boxes, like the one
shown here, don't contain a neutral
wire. Choose a replacement that
doesn't require a neutral.
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Switch that requires a neutral
Many of today's smart switches, like the
one shown above, require a neutral wire
to work properly. This switch box contains
a neutral wire.
Switch makers have built all kinds of cool
features into modern “smart switches.” You
can buy switches with occupancy sensors,
timers and programmable dimmers. But
the catch is that, unlike an ordinary switch,
some of these new switches require a neutral
to operate correctly. This is a problem if
your old switch is wired as a “switch loop,”
such that only a hot and a switched hot are
available in the box.
Before you shop for a new switch,
remove your old one from the box—after
making sure the power is off, of course—and look for a neutral white wire. Any wires
connected to the existing switch are not
neutral wires. If a white wire is connected to
the switch, it should be marked as a hot
wire with either a piece of black tape or
black marker as shown at right. If there's no
neutral in the box, shop for a smart switch
that doesn't require a neutral. One of the
photos shows a programmable timer switch
that requires a neutral.
Tip 5: Choose the right outlet
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Tamper-resistant outlets have covers over the internal contacts.
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Tamper-resistant, weather-resistant outlet
Weather-resistant outlets are required in certain outdoor locations.
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Arc-fault circuit interrupter
Arc-fault interrupters are required in most living areas.
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Ground-fault circuit interrupter
Ground-fault circuit interrupters are required in kitchens, bathrooms, and other damp areas.
In an attempt to reduce the risk of electrocution and fires,
the National Electrical Code requires specific types of outlets in
certain locations. Tamper-resistant outlets are required everywhere,
weather-resistant in certain outdoor locations, and GFCIs in
areas where dampness or water could contribute to a dangerous
shock (kitchens, bathrooms, garages, outdoors). Arc-fault interrupters
stop arcing that can cause fires and are required in most
living areas. Before you install a new outlet, check the code or consult
with someone who's familiar with code requirements to see
which type of outlet you should use.
Tip 6: Fold wires neatly
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Neatly folded wires
Bend the wires so that they neatly fold back into the box.
It's surprising how easily an outlet or switch goes into the
box if you fold the wires correctly. The trick is to make an
“accordion” out of the wires so you can push the device in without
crunching the wires. Another advantage of neat folds like
this is that they reduce strain on the wires and keep you from
accidentally creating a loose connection as you press the device
into the box.
Tip 7: Make a tight connection
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Bend the wire around the screw terminal clockwise, then tighten.
Most outlets and switches have a strip gauge on the
back. Use it to determine the correct length of bare wire
to leave exposed when you strip the insulation. If there is no strip
gauge, expose 3/4 in. of bare wire. Bend a loop in the wire. Most
wire strippers have a hole that you can stick the wire through to
bend the loop. Otherwise, use the nose of the stripper or needle-nose pliers. Slip the loop over the terminal screw, making
sure it's going around in a clockwise direction.
Then pinch the open end of the loop
with your stripper or pliers so that it encircles
the screw. Finally, snug up the screw.
Don't use the “stab-in” holes on the back
of the device or stack two wires under the
Tip 8: Match the breakaway tab to the original outlet
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Snap off a breakaway tab
Wriggle the tab up and down to snap it off when required.
There are a few different reasons that an outlet breakaway tab may be
removed. If one-half of a duplex outlet is controlled by a wall switch, then the hot tab,
and possibly the neutral tab, will be broken off. Or if the top and bottom outlets of a
duplex receptacle are powered by two different circuits, the hot tab and possibly the
neutral tab will be removed. In any case, when you replace an old outlet, check to see
whether the tabs are removed, and if so, break off the tabs on your new outlet to
match. Grab the tab with the end of a pliers or your stripping tool and wiggle it up and
down to break it off.
Tip 9: Extend short wires
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Splice short wires
Splice pigtails so they extend at least 6-in. beyond the face of the box.
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In-line splice connectors
In-line splice connectors are easy to use and take up little room in the box.
Wires that don't extend much beyond the
box are a violation of National Electrical
Code requirements. And besides, short
wires make it very difficult to hook up your
new switch or outlet. Luckily, the fix is
simple. Just splice 6-in. pigtails to the short
wires. You can connect the pigtails with
regular wire connectors, or use in-line splice
connectors like the ones shown. In either
case, check the label on the wire connector
package to see how much bare wire to
expose when you strip the insulation.
Tip 10: Don't scrimp on switches and outlets
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Switch quality comparison
Higher quality switches have better components.
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Outlet quality comparison
Higher quality outlets are more durable and operate more smoothly.
Better-quality switches and outlets may
cost a dollar or two more, but they're
worth it. For starters, the components
are better. They feel more substantial
and will last longer. And an added benefit
is that many include a “back-wire” feature,
not to be confused with cheap
“stab-in” connections, which we don't
recommend using. The back-wire feature
still relies on the terminal screw to clamp
the wire, but you don't have to bend the
wire around the screw. Just strip it, push
it in and tighten the screw.