Siemens – 3TK2820‑2CB30 – SIRIUS Safety Relay, 24 V AC/DC, 3NO + 1NC, SIL 3 / PL

The Siemens 3TK2820‑2CB30 (also 3TK28202CB30) is a compact DIN‑rail SIRIUS safety relay featuring three enabling circuits (NO) and one signaling contact (NC). It supports 24 V AC/DC operation, spring-type terminals, and both auto-start and monitored-start modes, delivering SIL 3 / Performance Level e across safety categories. Suitable for emergency stops, interlock and guard monitoring in high-safety industrial applications.  

Key Features & Specifications

• Model: 3TK2820‑2CB30 – Safety relay enabling circuits, 22.5 mm wide  

• Safety Performance: SIL 3 (IEC 61508), PL e (Category 4, EN 13849‑1)  

• Voltage: 24 V AC/DC

• Contacts: 3 × NO (enabling), 1 × NC (signaling)  

• Start Modes: Switchable auto-start or monitored start for emergency-stop circuits  

• Terminals: Spring-type IDC for fast wiring

• Housing: 22.5 mm DIN‑rail; IP40 protection, terminals finger-safe  

• Reliability: 0.291 kg, 300 V rated insulation, 4 kV impulse withstand, suitable for Class A EMC environments