30
2
Operating characteristics and performance
2-5 Durability
2-5-4 Switching durability of accessories
As Table 2-14 indicates, MCCB accessories whose switching
capability requires consideration can be grouped into two
types: accessories that are actuated by the switching of the
MCCB, and those that are actuated when the MCCB trips.
Accessories of the former type require a switching durability
equivalent to the associated MCCB. They provide the durability
specified by the total number of switching operations both with
and without current as given in Table 2-14.
Table 2-14 Switching durability of MCCB accessories
Accessory actuated by
switching of MCCB
Accessory actuated when
the MCCB trips
Accessory
built into the
MCCB
Auxiliary switch (W)
Alarm switch (K)
Shunt trip device (F)
Undervoltage trip device (R)
External
accessory
Operating handle (N, V)
Motor operating
mechanism (M)
Durability
Total number of switching
operations both with and
without current as given
in Table 2-12.
10% or more of the total
number of switching
operations both with and
without current as given in
Table 2-12.