Siemens NGB1B050B Circuit Breaker

Siemens NGB1B050B is a 1-pole molded-case circuit breaker (MCCB) rated for 50 A, designed for 480Y/277 V AC four-wire distribution. The NGB family provides thermal-magnetic overcurrent protection for a single hot conductor and is UL489-listed for use in Siemens panelboards and other compatible equipment. This unit uses load-lug terminations and is capable of interrupting faults up to 14 kA, helping protect feeders and downstream circuits in commercial and light-industrial installations. It is commonly employed to protect individual branch circuits or feeders within Siemens 480Y/277 V distribution schemes, aligning with panelboard configurations that specify Siemens MCCBs in the 50 A range. Given its 1-pole construction and 50 A rating, it is suited for circuits that require reliable, code-compliant protection of a single live leg in four-wire electrical systems.