UFC 3 -520-01
June 10, 2002
Feeder--The circuit conductor and components between the main and the branch
Filter--A general term used to describe equipment whose purpose is to reduce
harmonic voltage or current distortion f lowing in or being impressed upon specific parts
of an electrical system.
Fixed Instantaneous Trip-- The portion of an overcurrent trip element that contains a
nonadjustable means of tripping a breaker instantaneously at or above a predetermined
level of current.
Frame--An assembly consisting of all parts of a circuit breaker with the exception of an
interchangeable trip unit.
Frame Rating-- The maximum continuous current rating for a given frame size.
Frame Size--A classification for a group of MCCBs that are physically interchangeable
with one another. Frame size is expressed in amperes and corresponds to the largest
ampere rated breaker within the given group.
Ground--A conducting connection, either intentional or accidental, by which an electric
circuit or equipment is connected to the earth, or to some conducting body of relatively
large extent that serves in place of the earth.
Grounded--An electrical connection that gives a circuit a direct positive path to ground.
Grounded Neutral--A point of an electrical system that is intentionally connected to
Grounded, Solidly --Connected directly through an adequate ground connection in
which no impedance has been intentionally inserted.
that is an integral multiple of the fundamental frequency.
Horizontal Exit--A passage from one building to an area of refuge and access to a
means of egress (per NFPA 101) in another building on approximately the same level;
or a passage through or around a fire barrier (2 hour minimum) to an area of refuge with
access to a means of egress (per NFPA 101) on approximately the same level in the
same building, that affords safety from fire and smoke originating from the area of
incidence and com municating areas.
as a function
Inrush Current--The inrush current of a machine or apparatus is the maximum current
that flows after being suddenly and fully energized.