Siemens 5SY4120-8 Miniature Circuit Breaker MCB

Siemens 5SY4120-8 is a one-pole SENTRON miniature circuit breaker (MCB) rated for 20 A in 230/400 V AC networks, delivering a 10 kA short-circuit breaking capacity for reliable overcurrent protection. This 5SY4-frame device uses a Type D tripping curve and is designed for DIN-rail installation with a compact footprint of 18 mm in width, about 90 mm high and 70 mm deep. It features a 440 V insulation voltage (Ui) and supports 50/60 Hz operation, making it suitable for distribution panels, control cabinets, and other low-voltage circuits requiring precise, compact protection. Common applications include branch protection in electrical distribution and industrial control panels where DIN-rail mounted protection is needed.