TRIP CHARACTERISTICS
Miniature Circuit Breaker (MCB)TYPE “B” CHARACTERISTICS
Developed primarily to protect conductors and low level signal devices such as PLCs. Instantaneous trip is three to five times the rated current of the Supplementary Protector (3~5 x In). The fast trip time of these devices minimizes damage to control circuit conductors from low-level faults.

TYPE “C” CHARACTERISTICS
Developed primarily for applications with moderate inrush currents such as lighting, control circuits and appliances. Instantaneous trip is three to five times the rated current of the Supple¬mentary Protector (5~10 x In). The higher instantaneous trip level prevents nuisance tripping, and components being protected can typically withstand higher fault currents without being damaged.

TYPE “D” CHARACTERISTICS
Developed primarily for applications with high inrush currents, i.e., transformers, and motors. Instantaneous trip is ten to twenty times the rated cur¬rent of the Supplementary Protector (10~20 x In). The high instantaneous trip level prevents nuisance tripping, and components being protected can typically withstand higher fault currents without being damaged.

DC CIRCUITS USE
Thermal Characteristics for SADID breakers are unaffected by the current applied, that is either direct current or alternatiting current. The magnetic trip current value increases by 40%. Eg. In the case; a breaker of tripping characteristic B and 10A rated current, its magnetic tripping value will be between 30A and 50A in alternating current. The magetic tripping value for this very same breaker in direct current will be between 42.4A and 70.7A .

For DC service, the MCBs full rated breaking capacity can be achieved without any reduction in performance by connecting protected poles in series. For values up to 48V=, 1 protected pole can be used unimpaired of the breaking capacity value. Between 48 and 100V=, 2 protected poles series connected can be used without reduction in the breaking capacity. Between 110 and 150V=, 3 protected poles series connected must be used, and 4 poles up to 200V=. Connected must be used, and 4 poles up to 200V=.

FM74-63 Series

Miniature Circuit Breaker Type FM76-63