The GS1LLB4 is a TeSys GS fuse switch disconnector body — a 4-pole, 160 A rated unit that takes BS type A4 fuses. It's the disconnect and short-circuit protection point for a motor branch circuit or distribution feeder, not a contactor. The 160 A rating at 400 V under AC-23B duty (the heavy motor-switching category per IEC 60947-3) means it handles frequent motor starts and stops at full load, not just isolation. The making capacity of 1600 A and breaking capacity of 1280 A at 400 V AC-23B tell you it can close onto and interrupt a fault — that's the switch-disconnector's job when the fuses are sized for the circuit.
The headline number is 160 A at 400 V AC-23B — that's the motor-switching current. But the same body also carries 125 A at 690 V AC-23A/B, so if your line voltage is higher, the current drops accordingly. The short-circuit withstand rating of 80 kA is the prospective fault current the body can survive when backed by the correct BS fuses — that's the coordination number your panel designer needs for SCCR. The 4-pole configuration (3 poles + neutral switched) is standard for three-phase distribution where you want to isolate the neutral. The BS fuse size A4 means the fuse-link dimensions follow the British Standard blade pattern — not DIN or NH. If your plant standardizes on BS fuses, this is the body. If you run DIN fuses, you need the GS1LU variant.
The body is 240 mm wide, 162 mm high, 123 mm deep. That's a substantial footprint; plan your gland plate and busbar clearance accordingly. The power circuit connects via bars or screw terminals accepting 50 to 95 mm² flexible cable. Tightening torque is 12 N·m on both control and power terminals — use a torque wrench; under-torqued joints on a 160 A circuit generate heat. IP20 with the terminal cover fitted (IEC 60529) — finger-safe inside the enclosure, not for outdoor or washdown locations. The TH protective treatment means it's tropicalized against humidity and fungus — fine for non-air-conditioned plant floors.
Designed and tested to IEC 60947-3 (switch-disconnectors) and IEC 60269-1/-2 (low-voltage fuses). The fire-resistance rating on the body is 960 °C per IEC 60695-2-1; the fuse cover is 850 °C. The rated impulse withstand voltage is 8 kV (Uimp), and the insulation voltage is 750 V AC. These are the numbers a quality doc controller needs for the declaration of conformity and the panel builder needs for the nameplate.