What it is and what it does
The Siemens 3RB2046-2EW1 is a SIRIUS solid-state overload relay for three-phase motor protection. It uses straight-through current transformers on the main circuit and provides a single NC auxiliary contact for trip signaling. Rated CLASS 20E, this relay allows a longer start-up time for high-inertia loads like fans, centrifuges, or crushers before tripping on overload — it's the right choice when the motor needs a few extra seconds to spin up without nuisance trips. ATEX approval PTB 06 ATEX 3001 Ex II (2) GD covers explosive gas and dust atmospheres.
Installation and wiring
Mounts stand-alone in any position — no special orientation needed. Fastening method is stand-alone installation, meaning it doesn't require a separate base or adapter plate for the panel. Control circuit wiring uses screw-type terminals accepting 0.5 to 4 mm² solid or 0.5 to 2.5 mm² finely stranded with ferrules, and 2x (0.5 to 2.5 mm²) solid or 2x (0.5 to 1.5 mm²) stranded. For AWG, auxiliary contacts accept 2x (20 to 14). Dimensions are 70 mm wide, 106 mm high, 124 mm deep — fits a standard 70 mm wide DIN-rail footprint with 0 mm spacing required upwards, forwards, backwards, and downwards, and only 6 mm at the side. Panel layout is straightforward.
Electrical ratings and environment
The NC auxiliary contact is rated for switching at various control voltages: 2 A at 24 V, 4 A at 120 V, 3 A at 230 V, and 0.55 A at 60 V, 0.3 A at 110 V, 0.3 A at 125 V, 0.11 A at 220 V. These cover common control supply levels in industrial panels. Power dissipation is only 0.02 W per pole — negligible heat inside the enclosure, so no derating for adjacent devices in a dense panel. Operates from -25 to +60 °C, stores and transports from -40 to +80 °C, and handles 100 % relative humidity during operation. Shock resistance is 15g for 11 ms — tough enough for most industrial machinery vibration. Surge voltage withstand is 8 kV, and EMC burst immunity is 2 kV on power ports and 1 kV on signal ports per IEC 61000-4-4, severity level 3 — solid for noisy industrial environments.
Lifecycle and compliance
RoHS compliance date is July 1, 2006 — it meets the original EU RoHS directive. No REACH or UL listing is on record in this spec set, but the ATEX certification covers European hazardous-area requirements.