Siemens 3VA1 100 A Manual page 522

Glossary
Rated short-circuit making capacity
The rated short-circuit making capacity
current that the circuit breaker can safely interrupt at a specific rated operational voltage and
rated frequency. Unlike other characteristic data, this is specified as a peak value.
With AC molded case circuit breakers, the rated short-circuit making capacity must be at
least equal to the rated short-circuit breaking capacity multiplied by a factor n.
The rated short-circuit making capacity is calculated to allow the molded case circuit breaker
to conduct the current during closing at a voltage of up to 110% inclusive of the rated
operational voltage.
Rated short-time current
Permissible rms value of the AC component of the prospective short-circuit current which the
switching device is capable of conducting for a specific time period, e.g. from 0.05 s to 1 s
(thermal short-circuit strength).
Rated short-time withstand current
The rated short-time withstand current
current and characterizes the thermal strength of a circuit of a switchgear assembly under
brief load conditions. The rated short-time withstand current calculation normally refers to a
period of 1 s. The reference time must be specified if it deviates from the above. The rated
short-time withstand current is specified for the distribution and/or main busbars of a
switchgear assembly.
Rated ultimate short-circuit breaking capacity
The rated ultimate short-circuit breaking capacity
a molded case circuit breaker is capable of interrupting (test sequence 0 - C0, formerly P -
1). After the molded case circuit breaker has cleared the short circuit, it is capable of tripping
with increased tolerances under overload conditions.
Limit value of rated ultimate short-circuit breaking capacity
The rated ultimate short-circuit breaking capacity
current which the protective device is capable of disconnecting in accordance with
regulations. Up to this value, the protective device is also allowed to be used in a network.
Rated ultimate short-circuit breaking capacity
The rated ultimate short-circuit breaking capacity
a molded case circuit breaker is capable of interrupting (test sequence 0 - C0, formerly P -
1). After the molded case circuit breaker has cleared the short circuit, it is capable of tripping
with increased tolerances under overload conditions.
Limit value of rated ultimate short-circuit breaking capacity
The rated ultimate short-circuit breaking capacity
current which the protective device is capable of disconnecting in accordance with
regulations. Up to this value, the protective device is also allowed to be used in a network.
522
I
of a molded case circuit breaker is the maximum
cm
I
is specified as an rms value of the short-circuit
cw
I
is the maximum short-circuit current that
cu
I
.
cu
I
is the maximum value of the short-circuit
cu
I
is the maximum short-circuit current that
cu
I
.
cu
I
is the maximum value of the short-circuit
cu
Manual, 04/2015, A5E03603177010-02
3VA molded case circuit breakers