The Siemens 3RQ4053-2SG30 is an output optocoupler relay from the SIRIUS 3RQ4 series, built in the narrow 6.2 mm housing. It switches a single normally-open (NO) contact rated for a thermal current of 5 A, with a control voltage range of 110-230 V AC/DC.
At just 6.2 mm wide, this coupling relay packs tightly on a DIN rail — useful when you need to isolate a PLC digital output from a higher-voltage load circuit without consuming a full-width interface relay. The push-in terminals match the same strip-and-insert rhythm as the rest of the SIRIUS 3RQ4 family, so wiremen can run the same 0.2–2.5 mm² wire gauge across the row. The 110-230 V AC/DC coil means it pulls directly from a line-voltage control transformer, skipping an intermediate 24 VDC power supply.