I
Symbol used to designate current

IACS
International Annealed Copper Standard for copper used in electrical conductors. 100% conductivity at 20ºC is 0.017241 ohm-mm²/m

ICEA
Insulated Cable Engineers Association . The association of cable manufacturing engineers who make nationally recognized specifications for cables. Formerly IPCEA

IEC
International Electrotechnical Commission. See CENELEC

IEEE
Institute of Electrical and Electronic Engineers. An international professional society that issues its own standards and is a member of ANSI and ISO

IEEE 10BASE2 Network
A network conforming to the IEEE 802.3 local area network standard. The network is capable of carrying information at rates up to 10 Mbps over distances up to 2,800 meters (9,184 feet)

IEEE 10BROAD36
10 million bits per second over broadband coaxial cable with node-to-node coverage of 3,600 meters. The IEEE 802.3 specification for running Ethernet on broadband

IEEE-488
An IEEE standard for a parallel interface bus consisting of eight bidirectional data lines, eight control lines, and eight signal grounds, which provides for connection to an IEEE-488 device

IEEE-802
Standards for the interconnection of local networking computer equipment. The IEEE-802 standard deals with the Physical Link Layers of the ISO Reference Model for OSL

IEEE 802.3
An IEEE standard describing the physical and data link layers of a local area network based on a bus topology and CSMA/CD

IEEE 802.4
A physical layer standard specifying a LAN with a token-passing access method on a bus topology. Used with Manufacturin Automation Protocol LANs

IEEE 802.5
A physical layer standard specifying a LAN with a token-passing access method on a ring topology. Used by IBM's token ring hardware

IEEE 802.7
A proposed physical layer standard specifying a LAN using both 802.3 and 802.4 standards

IF
Intermediate-frequency

Impact Tests
Tests designed to reveal the behaviour of material of a finshed part if it were subjected to impact or shock loading

Impedance
The total opposition a circuit, cable, or component offers to alternating current. It includes both resistance and reactance and is generally expressed in ohms

Impedance, High
Generally, the area of 25,000 ohms or higher

Impedance, Low
Generally, the area of 1 through 600 ohms

ImpedanceMatch
A condition whereby the impedance of a particular cable or component is the same as the impedance of the circuit, cable, or device to which it is connected

Impedance MatchingStub
A section of transmission line or a pair of conductors cut to match the impedance of a load. Also called Matching Stub

Impedance Matching Transformer
A transformer designed to match the impedance of one circuit to that of another

IMSA
International Municipal Signal Association

In-Band Signalling
The transmission of signalling information at some frequency or frequencies that lie within a carrier channel normally used for information transmission

Incoherent Source
A fiber optic light source which emits wide, diffuse beams of light of many wave lengths

Index Edge
Edge of flat (ribbon) cable from which measurements are made, normally indicated by the location of the printing which is near the index edge. Sometimes indicated by a thread or other identification tripe

Indoor Termination
A cable termination intended for use where it is protected from direct exposure to both solar radiation and precipitation

Inductance
A property of a conductor or circuit which resists a change in current. It causes current changes to lag behind voltage changes and is measured in henrys

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

Induction Heating
Heating a conducting material by placing it in a rapidly changing magnetic field. The changing field induces electric currents in the material field and I²R losses account for the resultant heat

Inductive Coupling
Cross talk resulting from the action of the electromagnetic field of one conductor on the other

Input
(1) A signal (or power) which is applied to a piece of electric apparatus
(2) The terminals on the apparatua to which a signal or power is applied

Insertion Loss
A measure of the attenuation of a device by determining the output of a system before and after the device is inserted into the system

Insertion Tool
A small, hand-held tool used to insert contacts into a connector

Insulated Radiant Heating Wire
Similar to blanket wire but heavier construction for applications such as in cailing panels, buried in ground or driveway and concrete walks

Insulated Splice
Aaplice with a dielectric medium applied over the connected conductors and adjacent cable insulation

Insulating (Isolating) Joint
A cable joint which mechanically couples and electrically separates the sheath, shield, and armor on contiguous lengths of cable

Insulation
A material having good dielectric properties which is used to separate close electrical components, such as cable conductors and circuit components

Insulation Level
A thickness rating for power cable insulation. Circuits having fault detectors which interrupt fault currents within 1 minute are rated 100% level, within 1 hour are rated 133% level, and over 1 hour are rated 173% level

Insulating Temperature Rating
A maximum temperature assigned to insulations based on laboratory tests

Insulation Resistance
The electrical resistance of an insulating material at a specific time and condition as measured between two conductors

Insulation Stress
The potential difference across an insulator. The stress on insulation is expressed in volts per mil (V/m) or kilovolts per meter (kV/m)

Insulation Thickness
The wall thickness of the applied insulation

Insulation Voltage Rating
The nominal phase-to-phase operating voltage of a three-phase cable system

Interaxial Spacing
Center-to-center conductor spacing in paired wire or center-to-center spacing between conductors in a flat cable

Intercalated Tapes
Two or more tapes helically wound and overlapping on a cable

Interconnecting Cable
The wiring between modules, between units, or the larger portions of a system

Interconnection
Mechanically joining devices together to complete an electrical circuit

Interface
The surfaces on the contact side of both halves of a multiple-contact connector which face each other when the connector is assembled

Interference
Disturbances of an electrical or electromagnetic nature that introduce undesirable responses into other electronic equipment

Intermediate Frequency
A frequency to which a signal is converted for ease of handling. Receives its name from the fact that it is an intermediate step between the initial and final conversion or detection stages

Intermediate Temper
As applied to aluminum, any temper between soft and hard drawn

Internal Wiring
Electronic wiring which interconnects components, usually within a sealed subsystem

Interstice
The space or void between assembled conductors and within the overall circumference of the assembly

Intrinsically Safe
Incapable of releasing sufficient electrical or thermal energy under normal or abnormal conditions to cause ignition of a specific hazardous atmosphereic mixture in its most ignitable concentration. See Article 504 of the NEC

I/O
Input/Output. The process of transmitting data to and from the processor and its peripherals

Ionization
(1) The creation of ions when polar compounds are dissolved in a solvent
(2) When a liquid, gas or solid is caused to lose or gain electrons due to the passage of an electric current

Ionization Factor
This is the difference between percent dissipation factors at two specified values of electrical stress; the lower of the two stresses is usually so selected that the effect of the ionization on dissipation factor at this stress is negligible

Ionization Voltage
The potential at which a material ionizes. The potential at which an atom gives up an electron

IR Drop
A method of designating a voltage drop in terms of noth current and resistance

Irradiation
In insulations, the exposure of the material to high-energy emissions for the purpose of favorably altering the molecular structure

ISO
International Standards Organization

ISO 9000
A set of quality standards widely used around the world

Isolation
The ability of a circuit or component to reject interference, usually expressed in dB

I²R
Formula for power in watts, where I 5 current in amperes, R 5 resistance in ohms. See Watt

IECEx Scheme
The objective of the IECEx Scheme is to facilitate international trade in electrical equipment intended for use in potentially explosive atmospheres by eliminating the need for multiple national certification. The IECEx Scheme provides a means for manufacturers to obtain Certificates of Conformity that will be accepted at national level in all participating countries. A Certificate of Conformity may be obtained from any certification body accepted into the scheme. The objective of the IECEx Scheme is world-wide acceptance of one standard, one certificate, and one mark

IECEx
The aim of the IECEx Scheme is to facilitate international trade in electrical equipment intended for use in potentially explosive atmospheres by eliminating the need for multiple national certificates

INMETRO
Instituto Nacional de Metrologia, Normalizacão Qualidade Industrial (Brazil)

ITS
Intertek Testing Services

Insulation & Jacket Materials
Conductors need to be electrically isolated from other conductors and from the environment to prevent short circuits. Insulation is applied around a conductor to provide this isolation. Most wire and cable insulations consist of polymers (plastics) which have a high resistance to the flow of electric current. A jacket is the outermost layer of a cable whose primary function is to protect the insulation and conductor core from external physical forces and chemical deterioration