Dryer Outlet Circuit
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Wiring a Dryer Receptacle & Circuit
Dryer wire cable between circuit panel and dryer plug is 10 AWG, black / red /
white / bare (or green). X & Y are interchangeable, red and black wires are
ungrounded (hot) wires, one wire on the X, and the other on the Y. The
grounded conductor (neutral
[white]) and the bare (or green) equipment ground wire MUST be on there designated connection.
In the diagram bellow the bare (or green) ground is indicated by a green line. The
bare (or green) wire should also be grounded to the electrical box (if metallic).
Be sure to use the properly rated electrical box designed to be used
with a dryer receptacle.
Ground = Equipment Grounding Conductor
X & Y = Interchangeable with the 2 Ungrounded Conductors (Hots)
White = Grounded Conductor (Neutral)
DRYER RECEPTACLE & CIRCUIT
The breaker used must be a dual (double pole) 30 amp 220v breaker. 220v
breaker meaning that the breaker must be of the type that actually
connects to both ungrounded (hot) bus bars in the panel, every other bus lug in the panel
is on the opposite phase of the incoming power line. refer to the
picture below and to the left.
If you were to measure the voltage between a red
lug and a black lug (they are not really those colors in the panel, just
used here for explanation purposes) , you would measure between 220 to
240v, if you
were to measure between a black bus lug and a ground or neutral bus, you
would measure 110 to 120v, and the same would hold true if you measure between
a red bus lug and the ground or neutral bus.
The equipment grounding bus is a terminal block with many small holes where the bare
ground (or green wire) can be connected and tightened into place with a
The grounded (neutral) bus is a terminal block also with many small holes where the
white neutral wire can be connected and tightened into place with a
A Safety Note about Breakers
A breaker designed to be used with 220v, is a dual (double pole) breaker
that actually when mounted into the panel connects to both ungrounded
conductors (hots) of the
incoming power , in other words connects to both the red and black panel
lugs (colors in illustration, your panel is not colored but will be
alternating between phases from one lug to the next). Sometimes in some
panels you may have a set of 4 breakers moulded together and they mount
in the panel over the 2 lugs , the middle 2 breakers would be the two 30
amp breakers and the outer 2 could be 15 or 20 amp breakers for use in
general purpose 110 v circuits. If you ask you local building or
electrical supply depot for a dual 30 amp breaker for use in a 220v
dryer circuit for this model/make breaker panel, they will be able to
pick out the correct breaker for you. Please note, electrical panels are
dangerous to work in, never touch any of the main ungrounded bus lugs in the panel,
they can kill! A breaker can be installed without physically touching
the ungrounded bus lugs. To be even safer you can switch the main
breaker off to de-activate the panel while installing the breaker, use a second person
to help with a flashlight if needed.
Also note that a 220 dual breaker has both breakers bridged so that if one
of the dual breakers where to trip then both sides of the dual double pole
breaker will shut down.
The equipment grounding wire connects to the equipment ground bus. Just look where all the
other bare (and green) equipment grounding wires are going in the panel.
The grounded conductor - white (neutral) wire gets connected to the neutral bus. Just look
where all the other white wires are going in your panel. Should be on
its own connection screw hole within the neutral bus.
The red and black wires (ungrounded conductors [hot]) from dryer cable connect to the dual 30 amp
breaker, one to each of the dual breakers.
Bellow is information on the older style 3 wire cords and
the new 4 wire cords
Although most times on this website I use
the electricians technical identification of wires but I have used the layman term bellow
(so it is not as much of a tongue twister in the explanation) as follows...
HOT - ungrounded conductor
NEUTRAL - grounded
GROUND - equipment grounding conductor
Dryer Cord - 3 wire hook-up at Dryer
Photo used with permission from Jeff Worrall at
3 wire dryer power systems are for use with existing ungrounded dryer
receptacles mainly in older homes whose wiring in years gone by was not
This picture above shows a dryer cord (at the dryer end) with 3 wires
only, No equipment ground wire. The center wire of this cable is the neutral wire
and the outer wires are hot live wires. The hot wires connect to the
outer 2 connections the power terminal block of the dryer, does not
matter which is which as long as one hot is connected to each of the
outer terminal connectors.
The center wire (neutral wire) of the cable goes to the center
connector. Since in this case the neutral serves as a neutral and a
ground connection, a jumper band (ground strap) is also connected to the
center terminal and to the frame of the dryer. A green wire could also
be used to connect the center connector to the frame of the dryer.
In the example in the picture the dryer doesn't have color designation
on the wires, follow direction above; if the dryer cord does have
colored wires, white is the neutral wire to the center connector, the
red and black wires are the hot live wires which connect to the 2 outer
connections of the dryer terminal block, don't forget the ground strap
or green wire jumper from the center connector to the dryer frame.
Note: All new dryer
circuit / receptacle installations must be grounded, which means you would
be using a 4 wire dryer cord with a new circuit install.
Dryer Cord - 4 wire hook-up at Dryer
Photo used with permission from Jeff Worrall at
A 4 wire dryer cord contains a black, red, white and green wire. The red
and black wires are hot live wires and get connected to the 2 outer
connectors on the dryers power terminal block, doesn't matter which is
which as long as it is the outer two connectors. The green wire is a
ground wire and gets connected to the frame of the dryer. The white wire
is a neutral wire and must be connected to the center connector on the
dryer power block. No ground strap is used in a 4 wire setup (grounded
circuit). In the sample picture above the ground strap in folded over
and is connected to the center connector but NO connection from it or
jump to ground. The ground strap could also be removed if you wish as it
is not needed in this installation.
250-138 new branch circuits for ranges and dryers and
250-140 existing branch circuits for ranges and dryers.
Use a 30 amp 240 volt double pole breaker in the panel. Run a 10/3wGrnd
Romex ®, cable. This cable should be rated as a 10 awg cable with a red,
black, white, and bare conductor in that cable. At the panel connect the
black and red wire to the 30 amp double pole breaker. Connect the white
and bare wire to the neutral / ground bars in the panel.
Run the cable concealed in crawl or in attic or in walls.
At the dryer end use a 30 amp rated 4 prong dryer receptacle. The black
connects to either the outside left connecting lug and the red connects
to the other outside connecting lug. The white connects to the center
connecting lug and the bare connects to the green connecting lug or
screw. All these connections are inside that 30 rated 4 prong dryer
The pigtail to your dryer will have to be changed to a 4 prong pigtail
with the two outside cables connecting to the two outside screws found
on the connecting block inside the dryer. The center white conductor is
connected to the center screw of that dryer connecting block. the bare
or green conductor connects to the metal frame of the dryer on a green
The above is for a new branch circuit serving an existing or new dryer.
If you can move an existing three prong dryer to your new desired
location then you may use this three prong receptacle still as existing
only if the cable is an SE type cable with a red, black, and bare
conductor. This bare conductor must wrap around the black and red wire
as a protector within that SE cable. If you have a cable that is Romex ®
but not with the identification of being an SE cable written on the side
of that cable, or the bare wire does not wrap the black and red
conductors, then you must upgrade that branch circuit to the new
requirements using a four conductor cable and a four prong receptacle as
described above at the beginning of this article.
If you are using a three prong receptacle as existing then the pigtail
must be a three prong pigtail with the two outside wires of that pigtail
connected to the two outside screws of the connecting block found in the
dryer. The center conductor of the pigtail is connected to the center
screw of that same connecting block inside the dryer. There must also be
a green jumper wire installed between the center connection on that
connecting block in the dryer and the metal frame of the dryer on a
Written: Dec. 21. 2011
Revised: June 22, 2013
Proof Read / Released: July 10, 2013
Diagrams redrawn with Transparency: Jan.
By: Donald Kerr