Schneider Electric NSB FA12040A Miniature Circuit Breaker

Square D by Schneider Electric FA12040A is a 40-amp, 1-pole miniature circuit breaker for 240 V circuits in residential and light commercial panels. It uses a thermal-magnetic trip mechanism and has a 25 kA interrupting rating at 120/240 VAC, providing robust overcurrent protection. This FA-series MCB accepts 14–1/0 AWG aluminum or copper conductors on the load side and features a line-side I-Line connection for streamlined panelboard installation. As part of the FA I-Line family, the FA12040A is intended for use in panelboards and service equipment that specify FA-style breakers, delivering reliable protection for individual branch circuits in distribution systems with 240 V operation. Its compact, 1-pole form factor suits spaces where space is limited while maintaining robust protection for circuits demanding up to 40 A.