The Schneider Electric Compact NSX100F 50A 4P 3D is a specialized 4-pole, 50A, fixed-type molded case circuit breaker (MCCB) from the Compact NSX series. The unique "3D" configuration indicates a 3-pole protected + 1 switched neutral design, providing a specific and cost-optimized solution for three-phase systems where the neutral conductor requires switching but not necessarily overcurrent protection.