Siemens 5SJ4105-8HG40 Sentron MCB – 0.5A, 1-Pole, 240V AC, D-Curve Trip, UL 489 Rated

The 5SJ4105-8HG40 is a thermal-magnetic circuit breaker that provides exceptionally precise protection for low-current loads. With its D-Curve tripping characteristic, it is engineered to handle high initial inrush currents (typically $10\text{x}$ to $20\text{x}$ the rated current) without nuisance tripping, making it perfect for protecting control transformers, power supplies, and small motors.