Glossary of Wire & Cable Terminology
R - a) Symbol for resistance (see resistance) or resistor. b) 600 volt copper conductor stranded or solid, rubber insulated, cotton braid (rubber filled tape 6 AWG and larger). Cotton braid saturated with moisture resisting, flame-retarding compound smoothly finished. Used for power wiring. c) Abbreviation for riser.
RAD - The unit of measure for a radiation dose which is absorbed, equal to 0.01 joule per kilogram.
RADAR - Acronym for radio detecting and ranging. A system that measures distances and usually the direction to an object by determining the amount of time required for electromagnetic energy to travel to and return from the object.
RADIO - A general term, principally an adjective, applied to the use of electromagnetic waves between 10 KHz and 3 GHz and, in particular, their transmission through space.
RAM EXTRUDER - Wire making machinery for pressure and heat extruding PTFE insulation over a conductor. A predetermined amount of cylindrical shaped molded PTFE powder is placed in a cylinder chamber. A ram is pushed through the cylinder by a jack screw, forcing the PTFE through an orifice or tip through which the conductor is moving and forms a homogeneous tube of insulation around the conductor. The unsintered insulated wire is then passed through a curing oven to complete the process. The limitation of a ram extruder is the size of the slug of preformed PTFE powder. Since it is of constant size, when the slug is exhausted it is the end of the run. It cannot be continuously fed. As the diameter increases, the maximum length of wire to be covered decreases.
RATED TEMPERATURE - The maximum temperature at which an electric component can operate for extended periods without loss of its basic properties.
RATED VOLTAGE - The maximum voltage at which an electric component can operate for extended periods without undue degradation or safety hazard.
REACTANCE - The part of the total impedance of a circuit not due to pure resistance, measured in ohms. Symbol X. It is the imaginary part of the complex impedance, Z given by:
Z = R +iX
where R is resistance, X is reactance and i equals .
Reactance is due to the presence of capacitance or inductance in a circuit. The effect of reactance is to cause the voltage and current to become out-of-phase.
RECEIVER - A detector and electronic circuitry to change optical signals to electrical signals.
REEL - Circular container on which wire is wound for storage or transit, usually made of wood or metal.
REFLECTION LOSS - The part of a signal which is lost due to reflection of power at a line discontinuity.
REFLOW SOLDERING - The process of connecting two solder coated conductive surfaces by remelting of the solder to cause fusion.
REFRACTIVE INDEX - The ratio of the speed of light in a vacuum to the speed of light in a material. Also called Index of Refraction.
REFRACTION - Deflection from a straight path undergone by a light ray or energy wave in passing obliquely from one medium (as air) into another (as glass) in which its velocity is different.
REPEATER - A device that receives signals in one circuit and automatically delivers corresponding signals
to one or more other circuits, usually amplifying the signal.
RESIN - A solid or semi-solid organic substance, originally of plant origin but largely synthesized now. It may be clear, yellowish, or brown, ranging from transparent to translucent; typically a nonconductor of electricity and soluble in organic solvents but not in water. Consequently, resins are widely used in insulating, potting, and encapsulating. Resins are broadly classified as thermoplastic or thermosetting according to whether they soften or harden with the application of heat.
RESISTANCE - The tendency of a material to resist the passage of an electric current and to convert electrical energy into heat energy. Symbol R. It is the ratio of the applied potential difference across a conductor to the current flowing through it (see Ohm’s law). If the current is an alternating current, the resistance, measured in ohms, is the real part of electrical impedance, Z, given by the formula:
Z = R +iX
where i equals and X is the reactance.
RESISTANCE WIRE - Wire constructed from a material, such as Nichrome® or constantan, that has a high resistivity and low temperature coefficient of resistance. It is used for accurate wire-wound resistors. Nichrome® is a trademark of the Driver Harris Company.
RESISTIVITY - An intrinsic property of a material equal to the resistance per unit length and unit cross sectional area. Reciprocal of conductivity. The lower the resistivity of a material the better conductor it is. Materials can be classified as conductors, semi-conductors, or insulators according to their resistivity. Conductors have a resistivity of 10-6 to 10-8 ohms per meter, semi-conductors have a resistivity of 10-6 to 10-7 ohms per meter, and insulators have a resistivity of 10-7 to 10-23 ohms per meter.
RESPOOL - To rerun material from one package spool to another for various purposes, such as to verify lengths, inspect for defects, or to a specified packaging by customer.
RETRACTILE CORD - A cord in which the insulation and/or jacket has been specially treated so that it will return to its original contracted form from an extended condition.
REV. - Abbreviation for revision.
RF - a) Abbreviation for radio frequency. b) Tinned copper conductors, rubber insulation, cotton braid saturated with moisture resisting, flame-retarding compound, smoothly finished in white, black, red, green, blue, and yellow for identification. The lubricated surface finish of the wire permits easy pulling through conduits.
RF CONNECTOR - Connector used for connecting or terminating coaxial cable.
RFI - Abbreviation for radio frequency interference.
RG - Abbreviation for Radio Frequency (Government). Prefix for many coaxial cables.
RHRW - Tinned copper conductors, rubber insulation, saturated braid, flame and moisture resistant finish for moist locations.
RHW - 75° C rubber insulated. Heat and moisture resistant insulation with an outer cover of moisture resistant, flame-retardant and a nonmetallic covering. Generally used in wet locations.
RIBBON CABLE - A flat cable with individually insulated conductors processed together in a parallel position. Conductors may be all in one color, or each individual conductor may be of a different color.
RIDGE MARKER - One or more ridges running laterally along the outer surface of plastic wire for purposes of identification.
RIGID COAXIAL CABLE - Non flexible coaxial cable, usually a metal tube armored coaxial cable.
RIGID WAVEGUIDE - A type of coaxial cable. A metal form (usually an extrusion) using air as a dielectric.
RIM Helix - Abbreviation for resin insulated magnet wire.
RIP CORD - A parallel construction of two or more insulated conductors which may be easily separated leaving the insulation of the conductors undisturbed.
RISER - A UL designation for cable approved to go from one floor to another floor in a multistory building.
RMS - Abbreviation for Root Mean Square. It is a means of expressing AC voltage in terms of DC. It is approximately 80% of AC peak voltage.
ROENTGEN - The amount of radiation that will produce one electrostatic unit of ions per cubic centimeter volume.
RoHS - RoHS is the acronym for Restriction of Hazardous Substances. RoHS, also known as Directive 2002/95/EC, originated in the European Union and restricts the use of specific hazardous materials found in electrical and electronic products. All applicable products in the EU market after July 1, 2006 must pass RoHS compliance. For the complete directive, see Directive 2002/95/EC of the European Parliament. The substances banned under RoHS are lead (Pb), mercury (Hg), cadmium (Cd), hexavalent chromium (CrVI), polybrominated biphenyls (PBB) and polybrominated diphenyl ethers (PBDE).
ROPE LAY STRAND - A conductor made of multiple groups of filaments. A 7 x 19 rope lay strand has 19 wires laid into a group and then 7 such groups laid cabled into a conductor.
RR - An all rubber nonmetallic underground cable suitable for direct burial in the earth or in conduit. It has heat and moisture resistant insulation and an outer Neoprene® jacket. Neoprene® is a trademark of the DuPont de Nemours Co.
RUB - Abbreviation for rubber.
RUBBER MOLD - A metal mold containing a cavity that will give the desired form or part. The part is made by placing uncured rubber or synthetic compound in the cavity and curing under heat and pressure.
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