DC-rated MCB for control-circuit and small-load protection
It is designed specifically for DC applications: the operating voltage is 220 VDC, with a maximum of 250 VDC, and it interrupts faults up to 10 kA at DC per IEC 60947-2.
Mounting and environment
Ambient temperature range is -40 °C to 75 °C, with humidity derating: max 95% RH up to 55 °C, tapering to 35% RH at 75 °C. That covers unheated storage and hot panel interiors near drives or transformers.
The 5SY5101-6CC is specified for mechanical engineering and industrial machine applications — the design-of-product field calls out machine manufacture / industry. In practice, that means it is a go-to for DC control circuits in packaging lines, conveyor systems, injection molders, and CNC machines where a 24 VDC or 48 VDC supply needs branch protection. The 1 A rating is low enough to protect a single PLC power supply output or a small sensor bus, but too low for a main feeder — it is a downstream branch device.