Glossary of Wire & Cable Terminology

A, B, C, D, E, F, G, H, I, J, K, L, M, N, O, P, Q, R, S, T, U, V, W, X, Y, Z


I - Symbol used to designate current. See current.

IAIACS - Abbreviation for International Annealed Copper Standard. Refined copper for electrical conductors: 100% conductivity at 20 C for 1 m X 1 mm2 has 1/58 ohm resistivity, 8.93 (changed to 8.89 in 1977) grams per mm2 density, 0.000017 per degree C coefficient of linear expansion, and 1/254.45 per degree C coefficient of variation of resistance.

IC - Abbreviation for integrated circuit.

ICEA - Abbreviation for Insulated Cable Engineers Association, formerly IPCEA.

ID - Abbreviation for identification.

I.D. - Abbreviation for inside diameter.

IEC - Abbreviation for International Electrotechnical
Commission, similar to the International Standards Organization (ISO).

IEEE - Abbreviation for Institute of Electrical and Electronic Engineers. Formerly American Institute of Electrical Engineers (AIEE) and Institute of Radio Engineers (IRE).

IMP - Abbreviation for impedance. See impedance.

IMPACT STRENGTH - A test for determining the mechanical punishment a cable can withstand without
physical or electrical breakdown by impacting with a given weight, dropped a given distance, in a controlled environment.

IMPEDANCE - A measure of the response of an electric circuit to an alternating current. Measured in ohms (volts per ampere). Symbol Z. The current is opposed by the capacitance and inductance of the circuit in addition to the resistance. The total opposition to current flow is the impedance, given by the formula:

Z = R +iX

  where R is resistance, X is reactance and i equals Glossary of Wire Cable Terminology.

The real part, the resistance, represents a loss of power due to dissipation. The imaginary part, the reactance, indicates the phase difference between the voltage and current. It is either positive or negative depending on whether the current lags or leads the voltage, respectively. In a circuit containing only resistance or in a resonant circuit, the current and voltage are in phase and Z is purely resistive. In a circuit containing only reactance, the current and voltage are out of phase and Z is purely imaginary, i.e., there is no dissipation in the circuit. Reciprocal of admittance. Abbreviated imp.

IMPEDANCE, HIGH - Generally, the area of 25,000 ohms or higher.

IMPEDANCE, LOW - Generally, the area of 1 through 600 ohms.

IMPREGNATED CABLE - A cable with paper insulation in which the insulating properties of the paper tapes are improved by impregnating them with an insulating compound, such as oil.

IMPULSE STRENGTH - The voltage breakdown of insulation under voltage surges on the order of microseconds in duration.

IMSASA - Abbreviation for International Municipal Signal Association, specification for fire alarm cable.

in - Abbreviation for inches.

INCL - Abbreviation for including.

INDEX OF REFRACTION - See refractive index.

INDIV - Abbreviation for individual.

INDUCED CURRENT - An electric current that flows in a conductor as a result of a changing magnetic flux density, in which lines of magnetic flux intersect with the conductor.

INDUCTANCE - The property of a circuit or circuit element that opposes a change in current flow, thus causing current changes to lag behind voltage changes. It is measured in henrys. Symbol L.

INDUCTION - The phenomenon of a voltage, magnetic
field, or electrostatic charge being produced in an object by lines of force from the source of such fields.

INDUCTIVE COUPLILING - Cross talk resulting from the electromagnetic field of one conductor on another.

INSERTION LOSS - The total optical power loss caused by the insertion of an optical component such as a connector, splice, or coupler.

INSULATION - That portion which is relied upon in a cable to segregate and protect the conductor from the other conductors, conducting parts, or from ground.

INSULATION LEVEL - The impulse voltage breakdown of cables and equipment.

INSULALATION RESISTANCE - The resistance offered by an insulating material to the flow of current resulting from an impressed DC voltage.

INSULALATOR - a) A nonconducting substance such as porcelain, plastic, glass, rubber, etc; b) a device made of such material used for separating or supporting conductors to prevent undesired flow of electricity.

INTERAXIAL SPACING - Center to center conductor spacing in paired wire; center to center spacing between conductors in a flat cable.

INTERCOM WIRE - Wire used to connect communication instruments, telephones, telegraphs, etc.

INTERLACED TAPES - Two or more tapes, generally of different composition, applied simultaneously in such a manner that a portion of each tape overlays a portion of the other tape.

INTERSTICE - A space that intervenes between things.

IPCEA - Abbreviation for Insulated Power Cable Engineers Association. Now ICEA.

IPE - Abbreviation for irradiated polyethylene tape.

IRE - Abbreviation for Institute of Radio Engineers, now IEEE.

IRON CONSTANTAN - A combination of metals used in thermocouple, thermocouple wires, and thermocouple lead wires. The iron wire is positive. The constantan is the negative wire.

IRRADIATION - In insulations, the exposure of the material to high energy emissions for the purpose of favorably altering the molecular structure by cross-linking.

ISA - Abbreviation for Instrument Society of America.

ISO - Abbreviation for International Standards Organization.

ISO 9000 - An international quality assurance program.

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