Rated performance for motor switching
Rated 125 A at 400 V AC-23A and AC-23B, and 100 A at 690 V AC-23A and AC-23B, so it handles motor loads up to those currents. For DC applications, it carries 100 A at 440 V with 2 poles in series per phase, DC-23A and DC-23B. Making capacity is 1000 A at 400 V AC-23B; breaking capacity is 10000 A at 400 V AC-23B.
Physical fit and mounting
Dimensions: depth 126.5 mm, width 184 mm, height 162 mm. Mounts on a plate. Power circuit terminals accept bars up to 20 mm² or lugs/ring terminals 35...95 mm², tightened to 12 N·m. IP20 with terminal cover.
Comparison with GS2KK3
The GS2KK3 is a 3-pole version of the same TeSys GS family, same fuse size 00 and DIN type. The GS2KK4 adds a fourth pole — if your circuit requires 4-pole isolation (e.g., three-phase plus neutral), the GS2KK4 is the correct choice; the GS2KK3 will not drop in without rewiring.