The GS1QQ4 is a TeSys GS fuse switch disconnector body — 4 poles, DIN-rail or plate mount, sized for T2 DIN fuses. It's the core switching element for a fused disconnect assembly in a panel, rated 400 A conventional free-air thermal current (Ith) at 40 °C, and 400 A in AC-23B duty at 400 V. That AC-23B rating covers occasional switching of motor loads or mixed resistive-inductive circuits — the making capacity is 4000 A at 400 V AC-23B, and the breaking capacity is 3200 A at the same condition. The 8 kV rated impulse withstand voltage (Uimp) and 800 V insulation voltage (Ui) tell you it's built for 400 V to 690 V line-to-line systems with solid clearance margins.
GS1QQ4 is officially obsolete per the manufacturer. If you're holding a legacy panel with this disconnect body, securing one as a critical spare before a failure is the prudent move; there's no direct drop-in from the current TeSys GS catalog without requalifying the mounting and fuse accommodation.
The disconnector body complies with IEC 60947-3 (switch-disconnectors), IEC 60269-1 (low-voltage fuses — general requirements), and IEC 60269-2 (supplement for fuses for industrial applications). The fuse cover withstands 850 °C glow-wire test per IEC 60695-2-1; the body passes 960 °C.
Power-circuit connections accept bars or screw terminals, with a tightening torque of 25 N·m on either. The terminal range handles 185 to 240 mm² flexible cable. The operating handle can be mounted externally on the front or the right side — typical for a panel-door interlocked disconnect. Mechanical durability is rated at 10,000 cycles; electrical durability at 1000 cycles for AC-23A/B and 200 cycles for DC-23A/B.