Integrator's quick read
The Siemens 5SY7305-7 is a 3-pole miniature circuit breaker from the SENTRON family, rated 0.5 A AC with a C-trip characteristic (5–10× In magnetic release). IP20 with conductors connected.
The 0.5 A rating is the continuous current at 35 °C; at 60 °C it derates to 0.42 A — if the breaker sits in a warm cabinet, size up one step. The C-curve handles moderate inrush from small transformers or contactor coils without nuisance tripping. Breaking capacity of 50 kA at 400 V AC (IEC 60947-2) gives headroom for high-fault installations; the 15 kA DC rating (per IEC 60947-2) covers battery-backed control circuits.
Snap-on DIN rail mount, any orientation. The 54 mm width occupies three 18 mm modular spaces. Combined terminal top and bottom accept supply from either side. Sealable cover option for tamper-proof installations. Halogen-free and silicon-free construction matters in clean-room or food-grade panels where outgassing is a concern.