The Siemens SENTRON 5SY1705-4 is a 1-pole device protection switch with an integrated auxiliary switch (1P+AS), rated 0.5 A at AC and 60 V at DC, with an F2 tripping characteristic. The IP20 finger-safe terminals keep live parts covered during commissioning.
The 0.5 A AC rating is the continuous current at ambient temperature; derate to 0.48 A at 35 °C, 0.46 A at 40 °C, and 0.4 A at 60 °C — so if the panel runs hot, the switch will trip earlier than the nameplate suggests. The F2 characteristic means a fast magnetic trip on short-circuit, with a lower threshold than a standard B or C curve; it's intended for protecting sensitive semiconductor loads or control transformers where a slower breaker might let fault current damage the downstream device. The 60 V DC rating covers most 24 VDC and 48 VDC control loops, but verify the DC breaking capacity matches your fault current — the spec doesn't list a DC interrupting rating, so treat it as suitable for low-energy DC circuits only.
The 18 mm width (1 MW) leaves room for adjacent modules. Vibration-resistant per IEC 60068-2-6. The auxiliary switch (1P+AS) provides a remote status signal — useful for PLC or SCADA monitoring of the protected circuit.