The Siemens 3RQ4018-2AB01 is a SIRIUS 3RQ4 output coupler relay in the narrow 6.2 mm housing. It provides one change-over contact rated for 6 A thermal current, with the coil accepting 24 V AC/DC. The spring-loaded push-in terminal (no tool required for solid or ferruled wire) saves panel build time compared to screw terminals. The hard gold-plated contacts suit low-level switching where oxide films on standard contacts would cause intermittent opens — think PLC digital outputs driving signal-level loads or sensor interfaces.
At 6.2 mm per channel, this relay packs densely on the DIN rail — roughly 10 units fit in a 65 mm span, leaving room for finger-duct or wireway. The 95 x 93 x 65 mm packaged dimensions give the panel wireman a clear idea of gland-plate clearance. Spring-loaded terminals accept 0.2–2.5 mm² solid or ferruled stranded; strip length around 8–10 mm ensures a clean seat under the cage. The narrow width means it slots into the last few positions on a rail where wider relays would overhang the end bracket.
Lifecycle and compliance posture
RoHS compliance is confirmed effective 26 September 2024, and REACH Article 33 candidate-list information is available on request. For BOM freeze or multi-year project planning, this part is a stable line item without a looming PCN.