What the 3RB2016-2NB0 is and where it fits
The Siemens 3RB2016-2NB0 is a SIRIUS solid-state overload relay — a CLASS 20E trip curve device for three-phase motor protection in control panels. It mounts directly onto a contactor (contactor mounting per), saving DIN-rail space and keeping the motor branch circuit compact. The 45 mm width matches the standard SIRIUS contactor footprint, so it slots into an existing panel layout without re-spacing. The CLASS 20E trip class allows a 20-second thermal overload before tripping.
ATEX and hazardous-area deployment
This relay carries ATEX approval PTB 06 ATEX 3001 Ex II (2) GD.
Termination and wiring constraints
Main current circuit terminals are screw-type, accepting 0.5 to 4 mm² solid (2× 0.5 to 2.5 mm²) or 2× AWG 18 to 14. Auxiliary and control circuit terminals also screw-type, accepting 2× AWG 20 to 14. The solid wire range covers standard panel-building practice — no need for ferrule conversion on solid runs. Finely stranded with core-end processing accepts 0.5 to 2.5 mm² (2× 0.5 to 1.5 mm²). Strip length and torque spec follow the SIRIUS wiring guidelines; verify free-wheel diode polarity on the contactor coil if sharing suppression.
Environmental and mechanical limits
Operates from -25 to +60 °C, stores and transports at -40 to +80 °C. Relative humidity tolerance is 100 % — suitable for condensing environments inside non-heated enclosures. Shock resistance is 15 g for 11 ms, which covers most industrial vibration profiles from conveyor drives and pump skids. Mounting position is any, so it fits vertical, horizontal, or inverted panel layouts without derating.
EMC immunity and surge withstand
Surge voltage resistance rated at 6 kV. Burst immunity per IEC 61000-4-4 is 2 kV on power ports, 1 kV on signal ports — severity degree 3. That covers most industrial installations without external surge suppression, though a Type 2 SPD on the panel feeder is still recommended for outdoor or long-cable runs.