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Picking the Wire Gauge
The higher the current flowing through a wire, the larger the wire gauge
(diameter) must be. Since a dryer pulls about 20 amps of current, you'll need
a wire gauge capable of handling at least that amount of current, if not
more. Most household utility circuits have 12-2 cable W/G (12-gauge wire, two
conductors hot and neutral with ground). But since the maximum load a
12-gauge wire can carry is 20 amps (and even less under certain conditions)
your dryer circuit should be wired with 10-gauge. Ten-gauge wire can carry a
maximum of 30 amps. Specifically, ask for 10-3 NM-B cable W/G (10-gauge wire,
three conductors, with ground).
Picking a Dryer Receptacle
The dryer receptacle must match the electrical requirements of the dryer.
Simply put, the receptacle must be listed for 120/240 volts, have internal
slots for three conductors plus ground, and be rated for at least the amount
of current flowing through it. Typically, a receptacle that meets these
requirements has two big slots side by side to accept the red and black
wires, one L-shaped slot that wires into the neutral, and a ground slot. Its
maximum current rating is 30 amps. But you don't have to remember all these
specs just ask for a new-style dryer receptacle, the one with four slots. The
old-style had the neutral and ground together and so had only three slots on
the receptacle face: hot, hot, and a combined neutral/ground. That
configuration is no longer up to code.
Safety Code requires that dryers must be on their own dedicated
circuit. Always completely finish wiring a dryer receptacle before you wire
its cable into a circuit breaker. Never wire the breaker first and think
you're safe in wiring the receptacle because you have the breaker turned off
someone may inadvertently turn the breaker on while you're handling the
wires.
Wiring the Receptacle
A few words about running 10-3 cable: It's so stiff that routine tasks like
fishing cable become major undertakings. But here are four quick tips to
speed the task.
- When you drill holes
to run cable through framing, use a chalk line to line up holes, and
drill as perpendicular to the studs or joists as possible. A right-angle
drill will help you do that; use a 1-inch bit.
- To reduce friction,
soap the holes liberally. Bar soap or dishwashing liquid are fine.
- Easier yet, you may
want to chisel out corners instead of drilling holes and not have to
pull cable at all. But you'll need to protect the cable by placing nail
plates over the slots you cut.
So, with a new four-slotted dryer receptacle in hand and
10-3 W/G cable coming into the space right behind the dryer, you're ready to
wire the receptacle. First attach the receptacle to the floor or wall. Pick a
place to mount the receptacle that won't interfere with the dryer's sliding
into its final location and that will allow you to unplug it easily. Even the
pros sometimes forget this latter point, which makes a contortionist out of
anyone who later has to unplug that dryer.
Once you've fixed a location for the receptacle, take the cover off the
receptacle and screw its metal base onto the floor or wall. (It's best if you
find a stud and screw into that.) The manufacturer has provided two screws
just for this purpose and you should throw them into your miscellaneous screw
jar. Instead of the pan-head, slotted screws the manufacturer gives you, shoot in two hex-head screws using your cordless
drill. That's what the pros do, anyhow and it's much faster and far less
tedious than hand-screwing the receptacle base.
Once that the receptacle is secure, you're ready to feed in the cable and
attach its wires to the terminals in the receptacle. Now it's time to wire
the dryer.
Step by Step
1. Strip about 6 inches of sheathing off the cable and feed it through
the receptacle clamp. Gently tighten down the clamp, making sure that the
section of cable gripped by the clamp is still sheathed.
2. Bend the individual wires so that they align to their slots.
Typically, printing on the receptacle base tells you which colored wire goes
where. It makes no difference which colored hot wire goes to which slot,
however there is no polarity.
3. Once you've aligned individual wires to their respective
terminal slots, cut them to length. The receptacle cover leaves little room
to fold wires, and 10-3 is quite stiff, so keep wire as short as is feasible.
Then strip about 1/2 inch of insulation off the end of each wire.
4. Push each bare wire end down into its slot. To do this, you may
first have to loosen the screw-tightening mechanism in the slot and swivel it
up and out of the way. Once the wires are in, swivel the mechanism back into
place and tighten the screws down onto the bare wire ends.
5. Put the cover back onto the receptacle, tighten the long
attachment screw that holds the cover to the base and you're done. Go forth
and dry.
TOOLS AND MATERIALS
Wire stripper
Dryer receptacle
Cordless drill/driver
10-3 NM-B cable with ground
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