What the adjustable settings mean for your panel
The RM4UA31F is a voltage measurement relay from the Schneider Harmony series, designed to monitor a single-phase AC line for overvoltage or undervoltage conditions — you select which mode by wiring the monitored parameter input. Two adjustments on the front face set the trip point: hysteresis is adjustable from 5 to 30 % of the voltage threshold setting, and the time delay is adjustable from 0.05 to 30 s. That 30 s ceiling lets you ride through motor inrush or generator recovery without nuisance tripping. The output is two C/O (changeover) contacts rated for 440 V AC switching — enough to control a contactor coil or signal a PLC input directly.
DIN-rail footprint and wiring
The relay occupies 22.5 mm (0.9 in) on the DIN rail — a standard single-module width — so it fits tightly in a crowded panel without wasting space. Terminals accept up to 2 x 2.5 mm² flexible wire without a cable end, or 2 x 1.5 mm² with a ferrule; tighten to 0.6...1.1 N·m. The screw terminals are clearly marked per ISO n°1, so you can land the control and output wiring without chasing a diagram. IP20 at the terminals, IP50 on the casing — fine for a dry indoor cabinet; keep washdown zones outside the enclosure.
Compliance and lifecycle status
Pollution degree 3 per IEC 60664-1 means it is rated for the typical industrial panel environment where conductive pollution or dry non-conductive pollution that becomes conductive due to condensation is expected.