The classic circuit breaker—a resettable overcurrent cutoff device—has been with us since the 1920s and is well-known for its reliable, consistent performance and a simple schematic symbol (Fig. 1).

Branch-circuit conductors must have overcurrent protection in accordance with Sec. 240.4, and the overcurrent protection device rating must not exceed the rating marked on the appliance [Sec. 422.11].

This circuit provides latching and high-speed overcurrent protection for power-factor corrected (PFC) boost converters operating at dc voltages to 380 V. Overcurrent damage of PFC front-end boost ...

Requiring only a handful of inexpensive components, the circuit breaker in Figure 1 responds to both overcurrent- and overvoltage-fault conditions. At the heart of the circuit, D 2, an adjustable, ...

Note: All Code references are based on the 2014 NEC. The NEC has separate sections for transformer feeder protection and transformer protection. Article 240 lists requirements for transformer feeder ...