Siemens 5SY7220-6 SENTRON MCB — 2-Pole, 20 A, B Curve
The Siemens 5SY7220-6 is a 2-pole miniature circuit breaker from the SENTRON series, rated 20 A with a B tripping characteristic. It carries dual breaking capacities: 15 kA per EN 60898-1 and 25 kA per IEC 60947-2, with UL 1077 recognition also listed. That 25 kA figure under 60947-2 is the one that matters for industrial panel coordination — it tells you this MCB can interrupt a fault up to 25 kA at the panel's rated voltage without needing an upstream current-limiting device. The B curve (3-5 In instantaneous trip) makes it a fit for resistive and general-purpose loads where inrush is modest — lighting circuits, control transformers, small motor starters with soft-start contactors.
Mounting and Panel Fit
Width is 36 mm, which is 2 modular units on a standard DIN rail. Depth is 76 mm; installation depth is 70 mm. Mounting position is any orientation — no derating needed for horizontal vs vertical rail. The quick-assembly fastening system snaps onto the DIN rail and the combined top and bottom terminals accept conductors for daisy-chaining. Sealable design allows the installer to lock the toggle position after commissioning. IP20 with connected conductors is the protection class — fine inside a closed panel, not for wet environments.
Temperature Performance and Derating
Rated 20 A at 35 °C ambient. At 40 °C it derates to 18.78 A, at 50 °C to 17.48 A, and at 60 °C to 16.08 A. Operating range is -40 °C to 75 °C. Humidity tolerance is specified as max 95% up to 55 °C, then derating to 55% at 70 °C and 35% at 75 °C. For a panel near a furnace or in a hot attic, the 50 °C derated figure (17.48 A) is the one to size the load against — not the 20 A label.
Lifecycle and Compliance
Production status is current — this is an active catalog item, not a phase-out or NRND part. Standards compliance covers IEC/EN 60898-1, IEC/EN 60947-2, and UL 1077. Overvoltage category III, pollution degree 3. Halogen-free and silicon-free construction. The product designation per EN 61346-2 and IEC 81346-2 is letter F. Suitability is marked for mechanical engineering and industry — the standard industrial MCB application.