What it is and what it does
The Siemens 3RB2046-1EX1 is a SIRIUS solid-state overload relay — a 3-pole device that protects motors against overload and phase failure by monitoring current through straight-through transformers. It's rated CLASS 10E, meaning it will trip within 10 seconds at 7.2× the set current, which is the standard for standard-start induction motors driving pumps, fans, and conveyors. The auxiliary circuit uses spring-loaded terminals (cage-clamp style), accepting 2x (0.25... 1.5 mm²) solid or finely stranded wire with ferrule. That's a clean, no-torque termination — fast for panel building, and stays tight under vibration. It carries ATEX approval PTB 06 ATEX 3001 Ex II (2) GD, so it can be installed in Zone 2 gas and Zone 22 dust hazardous areas when paired with an appropriate motor and enclosure. The surge voltage resistance is rated 8 kV, and it withstands 2 kV burst on power ports per IEC 61000-4-4 severity level 3 — solid for industrial environments with switching transients.
Mounting and integration
Mounts in any position — stand-alone installation, no DIN rail required. Dimensions: 70 mm wide, 106 mm tall, 124 mm deep. Clearance: 0 mm upwards, forwards, backwards, and downwards; 6 mm at the side. That zero-clearance top and bottom means you can stack it tight in a panel without worrying about airflow for heat dissipation — the solid-state design keeps self-heating low at 0.02 W per pole. Shock resistance is 15g / 11 ms, so it holds up on a machine frame or in a mobile equipment panel. Operating temperature range is -25 to +60 °C, storage and transport -40 to +80 °C, with 100% relative humidity allowed during operation — no derating needed in condensing environments.
Key ratings at a glance
Auxiliary contact ratings: 1 NC contact (no NO). Switching capacity: 4 A at 120 V, 3 A at 230 V, 2 A at 24 V, 0.55 A at 60 V, 0.3 A at 110/125 V, 0.11 A at 220 V. That covers most PLC input and contactor coil loads — just watch the 24 V DC rating if you're driving multiple small relays.