Download ELECTRICAL RECEPTACLES

ELECTRICAL RECEPTACLES
W. C. “Buster” Hounshell
Spring 2002
Standard Duplex Receptacle
• Has two halves for
receiving plugs
• Each half has a long
(neutral) slot
• A short (hot) slot
• A U-shaped grounding
hole
Standard Duplex Receptacle
• The slots fit the wide
prong, narrow prong,
and grounding prong
of a three-prong plug
• This ensures that the
connection between
receptacle and plug
will be polarized and
grounded for safety
Standard Duplex Receptacle
Wire attachment
• Wires are attached to the
receptacle at screw
terminals or push-in
fittings
• A connecting tab between
the screw terminals allows
a variety of different
wiring configurations
• Receptacles also include
mounting straps for
attaching to electrical
boxes
Standard Duplex Receptacle
Testing Agent’s Approval
• Stamps of approval
from testing agencies
are found on the front
and back of the
receptacle
• Look for the symbol UL
or UND. LAB. INC.
• Make sure the
receptacle meets the
strict standards of
Underwriters
Laboratories
Standard Duplex Receptacle
Amps and Voltage Ratings
• The receptacle is
marked with ratings for
maximum volts and
amps
• The common receptacle
is marked 15A, 125V
• Receptacles marked
CU or COPPER are
used with solid copper
wire
Standard Duplex Receptacle
• Those marked CUCLAD ONLY are used
with copper-coated
aluminum wire
• Only receptacles
marked CO/ALR may
be used with solid
aluminum wiring
• Receptacles marked
AL/CU no longer may
be used with aluminum
wire
Basic Types of Receptacles
• Several different types of receptacles are
found in the typical home
• Each has a unique arrangement of slots that
accepts only a certain kind of plug, and each
is designed for a specific job.
• Household receptacles provide two types of
voltage
– Normal and
– High voltage
Normal Voltage Receptacles
• Voltage ratings have changed slightly
over the years
• Normal receptacles should be rated for
110, 115, or 125 volts115, 120, or 125
volts
• For purposes of replacement, these
ratings are considered identical
High Voltage Receptacles
• High- voltage receptacles are rated at
220, 240, or 250 volts. These ratings
are considered identical.
• When replacing a receptacle, check the
amperage rating of the circuit at the
main service panel
• Buy a receptacle with the correct
amperage rating
15 amps, 125 volts
• 15 amps, 125 volts
• Polarized two-slot
receptacle is
common in homes
built before 1960
• Slots are different
sizes to accept
polarized plugs
1 5 amps, 125 volts
• Three-slot grounded
receptacle has two
different size slots
and a U-shaped
hole for grounding
• It is required in all
new wiring
installations
20 amps, 125 volts
• This three-slot
grounded receptacle
features a special Tshaped slot
• It is installed for use
with large appliances or
portable tools that
require 20 amps of
current
15 amps, 250 volts
• This receptacle is used
primarily for window
air conditioners
• It is available as a
single unit
• Or as half of a duplex
receptacle
• With the other half
wired for 125 volts
30 amps, 125/250 volts.
• This receptacle is
used for clothes
dryers
• It provides highvoltage current for
heating coils and
• 125-volt current to
run lights and timers
50 amps, 125/250 volts
• This receptacle is used
for ranges
• The high-voltage
current powers heating
coils
• The 125-volt current
runs clocks and lights
High-voltage Receptacles
• High-voltage
receptacles provide
current to large
appliances like clothes
dryers, ranges, water
heaters, and air
conditioners
• The slot configuration of
a high-voltage
receptacle will not
accept a plug rated for
125 volts
High-voltage Receptacles
• A receptacle rated for
125/250 volts has two
incoming hot wires,
each carrying 125 volts
• A white neutral wire,
and a bare copper
grounding wire
• Connections are made
with setscrew terminals
at the back of the
receptacle
High-voltage Receptacles
• Standard receptacle
rated for 250 volts has
two incoming hot wires
• No neutral wire
• A grounding wire is
pigtailed to the
receptacle and to the
metal receptacle box.