23 January 2021
What do the B curve, C curve, D curve, K curve and Z curve designations mean on Multi 9 breakers?
For C60 Multi-9 devices, AC rated, the following is the meaning of the trip curves (in reference to instantaneous trip rating):
B curve: 3.2 - 4.8 times amp rating for UL489 and UL1077 (3 - 5 times amp rating for IEC)
C curve: 7 - 10 times amp rating
D curve: 10 - 14 times amp rating
K curve: 10 - 14 times amp rating
Z curve: 2.4 to 3.6 times amp rating
Trip curves are included in the 0860CT0201 catalog.