Circuit Breaker Definitions - Article 100

[ali hassan]

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Circuit Breaker
A device designed to open and close a circuit by non-automatic means
and to open the circuit automatically on a predetermined overcurrent
without damage to itself when properly applied within its rating.
FPN: The automatic opening means can be integral, direct acting with
the circuit breaker, or remote from the circuit breaker.
Or
A switching device capable of making, carrying, and interrupting
currents under normal circuit conditions, and also of making, carrying
for a specified time, and interrupting currents under specified
abnormal circuit conditions, such as those of short circuit.

Adjustable (as applied to circuit breakers):
A qualifying term indicating that the circuit breaker can be set to
trip at various values of current, time, or both, within a
predetermined range.

Instantaneous Trip (as applied to circuit breakers):
A qualifying term indicating that no delay is purposely introduced in
the tripping action of the circuit breaker.

Inverse Time (as applied to circuit breakers):
A qualifying term indicating that there is purposely introduced a
delay in the tripping action of the circuit breaker, which delay
decreases as the magnitude of the current increases.

Nonadjustable (as applied to circuit breakers):
A qualifying term indicating that the circuit breaker does not have
any adjustment to alter the value of current at which it will trip or
the time required for its operation.

Interchangeable (as applied to circuit breakers):
The user cannot change the trip unit in many circuit breakers, but
some circuit breakers have an interchangeable trip unit, this feature
allows the user to change the continuous current rating of the breaker
without replacing the breaker, this is done by replacing the trip unit
with one of a different rating.

Setting (of circuit breakers):
The value of current, time, or both, at which an adjustable circuit
breaker is set to trip.

Device:
A unit of an electrical system that is intended to carry but not
utilize electric energy.
Components (such as switches, circuit breakers, fuseholders,
receptacles, attachment plugs, and lampholders) that distribute or
control but do not consume electricity are considered devices.

Disconnecting Means:
A device, or group of devices, or other means by which the conductors
of a circuit can be disconnected from their source of supply.

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