The Siemens 3RT2337-3NB30 is a 4-pole SIRIUS 3RT.3 contactor rated 110 A in AC-1 duty at 400 V and 40 °C ambient — that resistive-heating rating is the one that governs continuous current in heater banks, lighting panels, or distribution loads where inrush is low. Main circuit lands on screw terminals, while the auxiliary (1 NO + 1 NC) and control wiring use spring-loaded terminals — a mixed termination scheme that saves time on the control wiring side while keeping power connections under a screw clamp.
Terminal layout and panel integration
Size S2 footprint — the packaging dimensions are 122.5 x 82 x 142 mm, so it occupies a standard contactor slot on the DIN rail. The mixed termination matters at the panel gland plate: power wires (main circuit) land on screw clamps, which accept larger cable cross-sections typical for 110 A; the auxiliary and control circuit land on spring-loaded terminals, which are faster to wire and less prone to loosening under vibration. Keep the control wiring to the spring terminals and the load wiring to the screw terminals — that's the intended split.
RoHS compliant since October 2014. Group code R711, product group 5338 — these are Siemens internal classification codes used for catalog filtering and cross-reference lookups.