The GS1KG3 is a TeSys GS fuse switch disconnector body — a 3-pole, NFC-type unit rated for 125 A at 400 V AC-23B and 100 A at 690 V AC-23B with the terminal cover fitted. It accepts 22 x 58 mm fuse links and mounts on a plate or rail inside a control panel. Breaking capacity is 1000 A at 400 V AC-23B, making capacity 1250 A at the same voltage — these are the fault-interruption and fault-make ratings respectively, and they govern whether this switch holds up under a short-circuit condition on the load side. The 8 kV rated impulse withstand voltage (Uimp) means it survives transient overvoltages common in industrial distribution without flashover.
The AC-23B duty rating (125 A at 400 V, 100 A at 690 V) is the motor-switching category — it covers occasional switching of motors and other highly inductive loads. If your application is purely resistive (heater banks), the AC-21 or AC-1 rating would be higher for the same switch, but this part is not rated in those categories. The DC-23A/B ratings at 100 A, 440 V with two poles in series per phase mean it handles DC motor or solenoid loads, but only when you series the poles to increase arc-gap. The 22 x 58 mm fuse size is a standard European NH (NFC) format — common across most European switch-disconnector lines. If your existing panel uses 22 x 58 mm gG or aM fuse links, these fit directly. The IP20 with terminal cover is touch-safe but not washdown; this lives inside a locked enclosure, not on the factory floor.
Designed and tested to IEC 60269-1, IEC 60269-2, and IEC 60947-3 — the international standards for low-voltage fuses and switch-disconnectors. The fire-resistance test at 850 °C on the fuse cover and 960 °C on the body (per IEC 60695-2-1) means it won't propagate a flame under fault conditions. No UL or CSA listing is on record for this specific variant, so if your panel requires a UL 508 listed switch, this is not the part for that job.