Brochure

PowerPact H-, J-, and L-Frame Circuit Breakers
Glossary
267
02/2016
© 2011–2016 Schneider Electric
All Rights Reserved
integral ground-fault protection for equipment = Equipment ground-fault protection on grounded
neutral systems provided by components internal to the circuit breaker.
interchangeable trip unit = A trip unit which can be interchanged by a user among circuit breaker
frames of the same design.
interrupting rating = The highest current at rated voltage available at the incoming terminals of the
circuit breaker. When the circuit breaker can be used at more than one voltage, the interrupting rating
will be shown on the circuit breaker for each voltage level. The interrupting rating of a circuit breaker
must be equal to or greater than the available short-circuit current at the point at which the circuit
breaker is applied to the system.
inverse time = A qualifying term indicating there is purposely introduced a delay in the tripping action
of the circuit breaker, which delay decreases as the magnitude of the current increases.
I
r
= See long-time pickup.
I
sd
= See short-time pickup.
I
2
t = See let-through current.
I
2
t IN (I
2
t ON) = An inverse time delay characteristic.
I
2
t OUT (I
2
t OFF) = A constant time delay characteristic.
latch check switch = A mechanically-operated switch which senses if the trip latch is reset.
let-through current = The peak current (measured in amperes) which passes through an overcurrent
protective device during an interruption.
let-through I
2
t = An expression related to energy (measured in ampere-squared seconds) which
passes through an overcurrent protective device during an interruption.
LI = A combination of adjustable trip functions including long-time ampere rating, long-time delay, and
instantaneous pickup.
lifting adapter = A device used with a crane, chain block or an optional lifting mechanism supplied
with switchgear for removing and installing a drawout circuit breaker or fuse truck.
LIG = A combination of adjustable trip functions including long-time ampere rating, long-time delay,
instantaneous pickup, ground-fault pickup and ground-fault delay.
limit switch = A switch mechanically operated by a device.
local current meter = An ammeter installed as part of the trip unit.
long-time ampere rating = An adjustment which, in combination with the installed rating plug,
establishes the continuous current rating of a full-function electronic trip circuit breaker.
long-time delay = The length of time the circuit breaker will carry a sustained overcurrent (greater
than the long-time pickup) before initiating a trip signal.
long-time pickup = The current level at which the circuit breaker long-time delay function begins timing.
low voltage power circuit breaker (LVPCB) = A circuit breaker tested to the ANSI C37 Standards
with a two-step stored-energy mechanism, an electronic trip system, and drawout construction.
LS = A combination of adjustable trip functions including long-time ampere rating, long-time delay,
short-time pickup, short-time delay and a defeatable instantaneous pickup.
LSG = A combination of adjustable trip functions including long-time ampere rating, long-time delay,
short-time pickup, short-time delay, defeatable instantaneous pickup, ground-fault pickup and ground-
fault delay.
LSI = A combination of adjustable trip functions including long-time ampere rating, long-time delay,
short-time pickup, short-time delay and defeatable instantaneous pickup.
LSIG = A combination of adjustable trip functions including long-time ampere rating, long-time delay,
short-time pickup, short-time delay, defeatable instantaneous pickup, ground-fault pickup and ground-
fault delay.