About Power Cords and Power Cord Manufacturers Including: AC Power
Cords, Cable Assembly, Cord Cover, Cord
Sets, Electric
Cords, Electrical Plugs, Electrical
Receptacles, Extension
Cords, International Power Cords, NEMA Power Cords & Power Supply Cords.
Power cords are detachable means of supplying electricity from a main power source to electrical equipment or appliances. Most
electric cords are
AC power cords, meaning they conduct electricity in the form of an alternating current. Power cords consist of a flexible cord with
electrical plugs at each end, one male and one female. The connecting cord itself is a
cable assembly comprised of a conducting medium, typically copper, surrounded by
cord covers of insulating material and an outer polymer or rubber jacket which protects the wire.
Power supply cords, which are permanently affixed to electrical equipment, and power
cord sets are utilized anywhere that electrical equipment and appliances are in use, including industrial, office, commercial and domestic settings.
Extension cords are cord sets with longer cords that allow equipment to be connected to electrical supplies dozens or hundreds of feet away, and are used for electrical power tools, lighting, sound equipment, shop equipment and many personal uses.
NEMA power cords are the standard for North American electrical plugs, cord voltage capacities and
electrical receptacles' configuration; other regions throughout the world have different standards to which
international power cords adhere.
The female plug connects to the appliance or electrical equipment. The male plug connects the electrical receptacle, electrical outlet or power supply. Power cord manufacturers classify molded male plugs by receptacle type and voltage; most countries or large regions have slightly different voltage standards and electrical receptacle configurations which may or may not be interchangeable with power cords from other locations. Standard and specialty North American connectors are "NEMA" connectors which have been standardized by the National Electrical Manufacturer's Association; NEMA standards currently have 15 different types which are not generally interchangeable in regions outside North America. The two most commonly used North American "NEMA" plug types are Type A, which have two conducting blades or prongs, and Type B, which have an additional third grounding rod. Both plug types are configured with a molded plastic body called a "jack" which holds the two blades apart, while the cord connects to the blades within the plug body. Inserting the blades into an electrical outlet, or receptacle, energizes the blades. Electricity then flows through the blades, the blade-cord connection and the power supply cord, providing electricity to the equipment.
When determining the appropriate power cord type for different applications, many factors are considered. Power cord manufacturers follow various specifications, including voltage rating, current rating, length, wire shape and size, jacket material, safety and sanitary material grades and maximum cable temperature, as well as the type of molded plug and female connector. Cord wires are either flat or round. Electric cord application determines which jacket material is ideal; jacks may be thermoformed from PVC, rubber, polychloroprene (neoprene) and textile construction. The size of the cord wire is determined by the amount of voltage that will be required to flow through the cord. Cord wire sizes and voltage capacities are given a designation in accordance with the American Wire Gauge (AWG) standards for wire sizes.
The National Electrical Manufacturers Association (NEMA) sets the standards power cord manufacturers follow for both male electric plugs and female electric plugs. A male electric plug may be polarized or non-polarized. An electric plug is polarized when the physical characteristics of the blades allow the plug to be connected to the electrical outlet in only one way. Three-prong electrical plugs are inherently polarized. Non-polarized plugs do not restrict the way the electrical plug is connected to the electrical outlet. Two-prong electrical plugs do not have a grounding pin but may be polarized if one blade is larger than the other. Polarization and grounding is especially important for certain higher voltage appliances and electrical equipment that could have a higher risk of electric shock when they become live. Polarization of an electric plug ensures that the equipment is connected to the neutral, or grounded, side of the circuit. Sensitive electrical equipment and products should only be used with polarized or grounding type cord sets.
Power Cord Types
- conduct alternating current from
one point to another. AC power cords consist of a conducting medium,
typically copper, surrounded by insulation and a jacket.
- are used for computers and related electronic
equipment.
- consist of several wires or cables collected into
a single unit with connectors on at least one end.
- are protective covers that guard loose cords and wires from hazardous situations.
- are power cords with a male electrical plug at one end and a female plug at the other.
- are conductive cables used to transfer AC power from a plug to an electrical device.
- Electrical plugs male electrical connectors with metal-blade contact prongs that connect
electrically with holes in the matching female electrical receptacle.
- are commonly known as outlets or sockets.
- are marked with necessary information pertaining
to their use, size and wattage rating. Extension cords are available
in
many lengths and are marked with a size, or gauge, which is based on
the American Wire Gauge (AWG) system.
- are
specially designed for rough, heavy-usage environments in industrial
or commercial applications. The head is constructed with
large flats having deeply contoured ridges that afford a non-slip grip,
and a heavy molded strain relief shroud protects the cord/plug union.
- are designed to meet the critical needs of medical
equipment applications. Heavy-duty solid brass blades and pins are
soldered or
welded to the conductors for added durability.
- International power cords are detachable means of supplying electricity from a foreign power
source to native electrical equipment or appliances that would
otherwise have been incompatible.
- NEMA power cords are the standard for North American electrical plugs, cord voltage capacities and electrical receptacles' configuration
- have
one blade that is wider than the other, which helps reduce the potential
for shock. Three-prong plugs are automatically
polarized, since they can be inserted only one way.
- are
flexible lengths of cord that have an attachment plug molded to their
ends and are used to transmit electrical energy
from the main supply to an electrical device. A power supply cord,
which could also have terminations or a molded strain relief on the
opposite end of the plug, is permanently installed in the device being
powered, as opposed to a cord set, which is detachable.
- allow users to plug in electrical equipment
close to walls without bending or damaging power cords and are available
in both a two-conductor (polarized or non-polarized) or three-conductor
configuration. The three-conductor plug could have the grounding
pin in the top or bottom location.
- have two vertical blades and a grounding
pin. They are polarized by default, since they can be plugged in
just one way.
- consist of two vertical
blades, one if which is neutral and the other is referred to as hot.
Two-conductor plugs,
which
have no grounding pin, are polarized or non-polarized.
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Power Cord Terms
- The ability of a
power cable
or material to resist surface wear.
- A current flow whose direction changes
in regular cycles.
- The North American standardized wire
and cable-sizing system for identifying wire diameter of copper conductors.
The higher the gauge number, the smaller the cable.
- Also known as "current carrying capacity," it
is the capability of handling electric current, as expressed in amperes.
- The time it takes for an arc to create a conductive
path in a material.
- Expressed in
decibels (db) per unit length, it is the loss of power in an electrical
system.
- A protective layer covering any part of a conductor or cable,
as well as its insulation or jacket.
- A covering of one or more wires made from fibrous or metallic
filaments that are interwoven in cylindrical form.
- The amount of voltage at which the insulation
between two conductors or a conductor and ground deteriorates.
- The twisting of wires together within the same
frequency, in order to achieve a specific gauge.
- Irreversible damage of the insulation due to the mechanical
force of pressure.
- A term describing the capability of any material
to carry an electrical charge, typically expressed in terms of the percentage
of conductivity of copper, which has 100% conductivity.
- Any material in which electrons can freely move from
atom to atom (i.e. electrical current flow). Conductors, which are usually
metal, could be a wire that is solid or a stranded multi-wire cable.
- A tube or trough through which wires and cables are run.
- A test used to determine if an electrical current
will flow continuously throughout the length of a wire or cable.
- A small insulated flexible cable made to withstand mechanical
abuse.
- An insulating material used in a cable to shield one
conductor from another.
- Electric
current that flows in one direction only.
- The complete path of an electrical current.
An electrical circuit is considered to be an open circuit when the continuity
is broken and a closed circuit when continuity is maintained.
- An international plug used by many European countries.
Europlug is the common name for the CEE 7/16 2.5 amp, Class II plug.
- A unit of electrical capacity.
- Resistance to the crystallization of metal,
eventually leading to the breakage of conductors and wires due to flexing.
- A flanged nylon housing that permits mounting
in a panel on the front of the equipment for an electrical inlet or outlet,
which is held in place by screws and bolts.
- The number of times an alternating current repeats
its cycle in one second, measured in Hertz (Hz). The standard international
frequency is 50Hz, while the standard North American frequency is 60Hz.
- An indication of the physical size of a wire or the wire
diameter specifications. The number of the gauge is in an inverse relationship
to the size of the wire (i.e. the larger the wire, the smaller the gauge
number).
- A complete circuit accomplished through a conductive connection
between an electrical circuit and the earth or another large conducting
body.
- A test applied to a cable to determine whether any damage
has occurred during shipment.
- Generally considered to be any operating voltage
over 600 volts.
- Formerly "IEC 320," it is the International
Electrotechnical Commission standard that applies to a series of connectors,
plugs, outlets and inlets designed for use on electrical or electronic
equipment, including such portable equipment as computers, printers and
medical equipment.
- A conductor of electricity covered by a non-conducting
material.
- Any material having high resistance to the flow of
electric current that protects the inner conductors of an electrical
cord.
- Material, usually extruded plastic or elastomer, that
covers wire and cable, providing protection and additional insulation.
- A cord that ends with a plug at one end and is utilized
for connecting equipment to a power outlet.
- The dissipation of energy without accomplishing useful work.
- A connector molded on one or both ends of a cable
or cord.
- A cord or cable complex containing more than one
conductor.
- A compilation of wiring practices
and requirements from the National Fire Protection Association (NFPA).
- Also called "polychloroprene," it is a synthetic
rubber that has good resistance to chemical, oil and flame.
- An abrasion resistant thermoplastic with effective chemical
resistance that is utilized for cable and wire jacketings, wiring devices,
connectors and plugs.
- A unit of measurement referring to electrical resistance.
- A female connection that supplies access to electricity
from a source of power.
- A receptacle, connector or plug that has round
pins or sleeve-type contacts.
- Also called an "attachment plug," it is the
cable mount portion of an electrical connection or male contact device
that has pins or blades protruding from the face.
- Often referred to as a jacket, it is the material that
is applied to the outermost part of a wire or cable. Sheaths are typically
made of extruded plastic or elastomer.
- In cables, a metallic layer that prevents electrostatic
or electromagnetic interference between wires and external fields when
placed around a conductor or group of conductors.
- An information conveying current, including digital, analog,
audio and video information.
- An electrical circuit that has a neutral, a line
and a ground.
- A device that establishes an electrical connection with
plugs through tension connections. Sockets could be metal contacts that
are either bent to receive the blade or pin or spring-loaded.
- Also called a "transient," it is the temporary
and relatively large increase in the voltage in an electric circuit or
cable.
- An electrical circuit that holds three lines and
a ground or three lines, a neutral and a ground. The three lines are
1201/4 out of phase with each other.
- The maximum voltage that can be continuously applied
to a wire in conformance to standards or specifications.
- Formerly designated as "FR-1," it is a rating
established by UL for wire and cables that pass a specifically designed
vertical flame test for flammability.
- Any cord that is designated
by Underwriters Laboratories, Inc. (UL) for outdoor use.
- A unit of measurement that refers to electric power.
- Any standard system of numerical designations for
wire sizes (e.g. the AWG).
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