[I]

IEC - International Electrotechnical Commission, similar to the ISO in structure and scope.

IEEE - Institute of Electrical and Electronics Engineers.

Impendence - The total opposition that a circuit offers to the flow of alternating current or any other varying current at a particular frequency.

IMSA - International Municipal Signal Association Specifications for Fire Alarm Cable.

Induced Current - an electrical current set up in a circuit by butting line of force; a current caused by electromagnetic induction.

Inductance - The property of wire which stores electrical current in a magnetic field around the wire. By coiling wire, the effect can be intensified. It is measured in Henrys.

Inductive Coupling - crosstalk resulting form the action of the electromagnetic field of one conductor on the other.

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

Insulation Level 100% - Cable for use on grounded systems or where the system is provided with relay protection such that ground faults will be cleared as rapidly as possible but in any case within one minute.

Insulation Level 133% - Cable for use on grounded systems or where the faulted section will be de-energized in a time not exceeding one hour.