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 MIL-HDBK-419A
GROUNDING CONDUCTOR -- (Green Wire) A conductor used to connect equipment or the grounded circuit
of a power system to the earth electrode subsystem.
HIGHER FREQUENCY GROUND -- The interconnected metallic network (equipotential plane) intended to
serve as a common reference for currents and voltages at frequencies above 30 kHz and in some cases above
300 kHz. Pulse and digital signals with rise and fall times of less than 1 microsecond are classified as higher
frequency signals.
INTERFACE -- Any electrical connection (encompassing power transfer, signaling, or control functions)
between two or more equipments or systems.
ISOKERAUNIC (or isoceraunic) -- Showing equal frequency of thunderstorms.
ISOLATION -- Physical and electrical arrangement of the parts of an equipment, system, or facility to
prevent uncontrolled electrical contact within or between the parts.
LIGHTNING PROTECTION SUBSYSTEM -- A complete subsystem consisting of air terminals, interconnecting
conductors, ground terminals, arresters and other connectors or fitting required to assure a lightning discharge
will be safely conducted to earth.
LOWER FREQUENCY GROUND -- A dedicated, single-point network intended to serve as a reference for
voltages and currents, whether signal, control or power, from dc to 30 kHz and some cases to 300 kHz. Pulse
and digital signals with rise and fall times greater than 1 microsecond are considered to be lower frequency
signals.
MAGNETIC FIELD -- A vector field produced by a continuous flow of charge.
MULTIPOINT GROUND -- More than one path to ground.
NATIONAL ELECTRICAL CODE (NEC) -- A standard governing the use of electrical wire, cable, and fixtures
installed in buildings. It is sponsored by the National Fire Protection Association (NFPA-70) under the auspices
of the American National Standards Institute (ANSI-CI).
NEAR FIELD -- The region of the field immediately surrounding an antenna where the inductive and
capacitive fields predominate. In this region the angular distribution of the field varies with distance from the
NEUTRAL -- The ac power system conductor which is intentionally grounded on the supply side of the first
service disconnect(ing) means. It is the low potential (white) side of a single phase ac circuit or the low
potential fourth wire of a three-phase wye distribution system. The neutral (grounded conductor) provides a
current return path for ac power currents whereas the grounding (or green) conductor does not, except during
fault conditions.
PENETRATION -- The passage through a partition or wall of an equipment or enclosure by a wire, cable, or
other conductive object.
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