A
Common abbreviation for Ampere

AAR
American Association of Railroads

Abrasion Resistance
Ability to resist surface wear

AB Switch
A coaxial cable switch capable of switching one cable to one of two branch cables, A or B

AC
(1) Alternating current
(2) A UL cable type with flexible metal tape armor

ACAR
Aluminum conductor, aluminum-reinforced cable

Accelerated Life Test
A test in which a cable is subjected to extreme conditions to determine the life of a cable

ACSR (Aluminum Conductor, Steel Reinforced)
A bare composite of aluminum and steel wires, usually aluminum around steel

ACSR/AW
Aluminum conductor, steel reinforced, using aluminum clad steel wire

ACSR/AZ
Aluminum conductor, steel reinforced, using aluminum steel wire

ACSR/GA
Aluminum conductor, steel reinforced, using Class A zinc-coated steel wire

ACSR/GB
Aluminum conductor, steel reinforced, using Class B zinc-coated steel wire

ACSR/GC
Aluminum conductor, steel reinforced, using Class C zinc-coated steel wire

A/D (Analog/Digital)
An integrated circuit device that converts analog signals to digital signals

Address
The location of a terminal, a peripheral device, a node, or any other unit or component in a network, or process control system

Adhesive-Bonded
Cables bonded by adding an adhesive coating to the surface of the cable components, then joining and curing the adhesive to form a cable. See Bonded Cables

Admittance
A measure of how easily alternating current flows in a circuit. Admittance is the reciprocal of impedance. It us expressed in mhos

AEIC
Association of Edison Illuminating Companies

Aerial Cable
A cable suspended in the air on poles or other overhead structure

AF
Audio Frequency

AGC
Automatic Gain Control

Aging
The irreversible change of material properties after exposure to an environment for an interval of time

AIA
Aluminum Interlocked Armor. A type of cable sheath

Air Core Cable
A cable in which the interstices in the cable core are not filled with a moisture barrier

Aircraft Wire
An electrical wire primarily designed for the extreme conditions (temperature, altitude, solvents, fuels, etc.) of airborne equipment

Air Spaces Coax
A coaxial cable in which air is basically the dielectric material. The conductor may be centered by means of a spirally wound synthetic filament, beads or braided filaments. This construction is also referred to as an air dielectric

AL
Aluminum

Alloy
A substance (usually metallic) composed of two or more individual substances

ALS
A type of cable consisting of insulated conductors enclosed in a continuous, closely fitting aluminum tube

Alternating Current
Electric current that periodically reverses direction, Alternating current is generally abbreviated AC

AM
Amplitude modulation. A method of adding information to an electronic signal where the height (amplitude) of the wave is changed to convey the added information

Ambient
Conditions existing at a location prior to energizing of equipment (example: ambient temperature)

Ampacity
The rms current which a device can carry within specified temperature limitations in a specified environment, dependant upon
a) a temperature rating
b) power loss
c) heat dissipation

Ampere
A standard unit of current. Designated as the amount of current that flows when one volt of emf is applied across one ohm of resistance. An ampere of current is flowing when one coulomb of charge is passing a point every second

Ampere-Turn
The product of amperes times the number of turns in a coil

Amplifier
A device used to boost the strength of an electronic signal

Amplitude
The maximum value of a varying wave form

Amplitude-Modulation (AM)
Transmission method in which variations in the voltage or current waveform of a signal carry encoded information

Analog
Not digital. A continuously varying waveform

Anneal
To soften and relieve strains in any solid material, such as metal or glass, by heating to just below its melting point and then slowly cooling it. This also generally lowers the tensile strength of the material, while improving its flex life

Annealed Wire
See Soft Wire

Annular Conductor
A number of wires stranded in reversed concentric layers around a core

Annunciator Wire
Usually single solid copper, sometimes twisted pair or triplexed for open wiring of bell circuits and other low voltage systems

ANSI
American National Standards Institute. An organization that publishes nationally recognized standards

Antenna Lead-In Wire
(Not coaxial) Parallel twin lead construction, plastic jacketed with fixed 300 ohm impedance for connecting a remote antenna to a receiver

Antenna Rotor Cable
Multiconductor flat or round cable used to supply power to a motorized antenna, and control wires for changing direction of rotation

Antioxidant
Retards or prevents degradation of materials exposed to oxygen (air)

Appliance Wire and Cable
A classification covering insulated wire and cable for internal wiring of appliances and equipment

ARC Resistance
The time required for an arc to establish a conductive path in a material

Armature
(1) Rotating machine: the member in which alternating voltage is generated
(2) Electromagnet: the member which is moved by magnetic force

Armor
Mechanical protector for cables; usually a helical winding of metal tape, formed so that each convolution locks mechanically upon the previous one (interlocked armor); may be a formed metal tube or a helical wrap of wires

Arrhenius Plot
A statistical method used to predict time-to-failure, based on a device's performance at different temperatures. One method is given in IEEE Standard 101

ASCII
American National Standard Code for Information Interchange. A seven bit parity code established by the American National Standards Institute to achieve compatibility among data services and consisting of 96 displayed upper and lower case characters and 32 nondisplayed control codes

Askarel
A synthetic insulating oil which is nonflammable but very toxic. It has been replaced by silicone oils

ASTM
American Society for Testing Materials. An organization that sets standards on various material tests for industry

Attenuation
The decrease in magnitude of a signal as it travels through any transmitting medium, such as a cable or circuitry. Attenuation is measured as a ratio (decibel)

Attenuation Constant
A rating for a cable or other transmitting medium, which is the relative rate of amplitude decrease of voltage or current in the direction of travel. It is measured in decibels per unit length of cable

Audio
A term used to describe sounds within the range of human hearing. Also used to describe services which are designed to operate within this range

Audio Frequency
The range of frequencies audible to the human ear. Usually 20 - 20,000 Hz

AUI
Attachment Unit Interface. The interface between the Ethernet/IEEE 802.3 controller and the baseband transceiver or broadband modem

AWG
American Wire Gauge. A wire diameter specification. The lower the the AWG number the larger the wire diameter

Area Classification (Classification of Locations)
The purpose of area classification is to provide a basis for the correct selection, installation and location of electrical and non-electrical equipment in those areas. Areas must be classified depending on the properties of the flammable vapors, liquids, gases, mists, combustible dusts or fibers that may be present and the likelihood that a flammable or combustible concentration or quantity is present.

The aim of area classification is to avoid ignition of flammable releases that may occur in the operation of facilities. The intent is to reduce to an acceptable level the probability of a flammable atmosphere and an ignition source occuring at the same time

ATEX 94/9/EC Directive
ATEX is the term used when referring to the European Unions (EU) Directive 94/9/EC.

The ATEX Directive main objectives are to guarantee the free circulation of goods within the European Union by aligning the technical and legal requirements of the Member States

"ATEX" is derived from the French "Atmosphères Explosibles".
The Directive is named: "Approximation of the laws of the Member States concerning equipment and protective sytems intended for use in potentially explosive atmospheres.
The Directive covers electrical and non-electrical equipment and protective systems intended for use in potentially explosive atmospheres in mining and surface industries

The Directive covers:

equipment and products that have potential ignition sources
protective systems - products that control the effects of incipient explosions
safety devices - products that may be outside a potentially explosive atmosphere but that have an explosion safety function
components - products that are intended to form parts of equipment or protective systems

To ensure compliance with the Directive, equipment must meet with the essential requirements specified in the Directive and be marked with the CE marking

The process of ensuring that equipment complies with the Directive, conformity assessment procedure (s) must be complied with. These procedurtes may involve a Notified Body. A Notified body is a body that is independent of the product manufacturer and the Directive. The Notifed body has to be approved and appointed by its government

Apparatus Marking - IEC and CENELEC (Group II)

AEx
A marking prefix for apparatus complying with one or more types of explosion protection techniques for installation in accordance with Article 505 of the NEC

AWG (American Wire Gauge)
AWG Wire Sizes (see table below)

AWG: In the American Wire Gauge (AWG), diameters can be calculated by applying the formula D(AWG)=.005·92((36-AWG)/39) inch. For the 00, 000, 0000 etc. gauges you use -1, -2, -3, which makes more sense that "double nought." This means that in American wire gage every 6 gauge decrease gives a doubling of the wire diameter area, and every 3 gauge decrease doubles the wire cross sectional area. Just like dB in signal levels

Metric Wire Gauges (see table below)

Metric Gauge: In the Metric Gauge scale, the gauge is 10 times the diameter in millimeters, so a 50 gauge metric wire would be 5 mm in diameter. Note that in AWG the diameter goes up as the gauge goes down metric is the opposite. Probably because of this confusion, most of the time metric sized wire is specified in millimeters rather than metric gauges

Load Carrying Capacities (see table below)

The following chart is a guideline of ampacity or copper wire current carrying capacity following the Handbook of Electronic Tables and Formulas for American Wire Gauge. As you might guess, the rated ampacities are just a rule of thumb. In careful engineering the insulation temperature limit, thickness, thermal conductivity, and air convection and temperature should all be taken into account. The Maximum Amps for Power Transmission uses the 700 circular mils per amp rule, which is very very conservative. The Maximum Amps for Chassis Wiring is also a conservative rating, but is meant for wiring in air, and not in a bundle. For short lengths of wire, such as is used in battery packs you should trade off the resistance and load with size, weight, and flexibility