The Siemens SENTRON 5TT5031-0 is an Insta contactor with 3 normally open and 1 normally closed contact, rated for 25 A operational current at 400 V AC and a 230 V AC coil. The 25 A AC-1 rating covers resistive and slightly inductive loads; for motor duty (AC-3), derate according to the manufacturer's guidelines — the 25 A figure is the thermal current, not the motor-starting current.
Mounting and thermal considerations
The manufacturer explicitly notes that spacers must be provided between units to ensure adequate heat dissipation — this is not optional; stacking contactors without the required air gap will cause nuisance tripping or accelerated aging of the coil and contacts. The installation depth is 64 mm, with an overall depth of 71 mm including the housing and terminals.