Siemens 5SY4520-5 — SENTRON MCB, 20 A, Characteristic A
It carries a 10 kA breaking capacity per EN 60898-1 and a 20 kA rating per IEC 60947-2 / UL 1077, so it handles both residential and industrial fault-current levels. The characteristic A curve trips between 2 and 3 times rated current — suited for protecting semiconductor circuits or long cable runs where fast reaction to low-level overcurrents is needed, not motor or transformer inrush.
At 35 °C ambient the 5SY4520-5 carries its full 20 A. At 40 °C it derates to 18.78 A, at 50 °C to 17.48 A, and at 60 °C to 16.08 A. The operating range spans -40 °C to 75 °C, with humidity limits: max 95 % RH up to 55 °C, then derated to 35 % at 75 °C. That covers most indoor industrial and outdoor cabinet environments.
The 5SY4520-5 snaps onto a DIN rail via the quick assembly system and occupies 2 modular width units (36 mm wide, 90 mm tall, 76 mm deep). Installation depth is 70 mm. It mounts in any position, and the supply cord can enter from any side. The terminals are combined (top and bottom), accepting conductors for a clean panel layout.
The 5SY4520-5 is certified to IEC / EN 60898-1 and IEC / EN 60947-2 / UL 1077. The enclosure is sealable and provides touch protection (IP20 with connected conductors). The product designation per EN 61346-2 and IEC 81346-2 is letter F (protective device).