630 A Fuse Switch Disconnector for Motor and Power Circuits
The GS1SB3 is a 3-pole fuse switch disconnector body from the TeSys GS range, designed for BS-type fuses. Its headline rating is 630 A at 400 V in AC-23B duty — the category for switching motor loads and other highly inductive circuits, where the making and breaking currents are higher than resistive loads. That 630 A figure at 40 °C free air (Ith) is the thermal current ceiling; the actual operational current (Ie) varies with voltage and duty, reaching 630 A at 400 V AC-23A/B and 500 A at 500 V in the same categories. Rated operational power spans 295 kW at 690 V AC-23A/B up to 400 kW at 690 V AC-23A/B, with intermediate ratings at 400 V and 500 V. The rated insulation voltage (Ui) is 1000 V AC, and the impulse withstand voltage (Uimp) is 12 kV, giving headroom for 690 V line-to-line systems with transient immunity.
Breaking and Making Capacity — SCCR Coordination
Breaking capacity is 5040 A at 400 V AC-23B; making capacity is 6300 A at the same voltage and duty. For fault-current coordination, the short-circuit making capacity (Icm) is rated at 630 kA at 400 V when protected by BS fuses — this is the fuse rating, not the disconnector's own interrupt rating. The disconnector itself is rated to close onto and withstand that fault level, but the fuses do the interrupting. This matters for panel SCCR: the upstream fuse selection governs the overall assembly rating. Standards compliance covers IEC 60947-3 for switch-disconnectors, plus IEC 60269-1 and IEC 60269-2 for the associated fuse systems. The fire-resistance rating is 1760 °F (960 °C) for the body and 1562 °F (850 °C) for the fuse cover per IEC 60695-2-1, which is the glow-wire test — relevant for panel builders needing to meet thermal runaway protection requirements.
Durability and Environmental Ratings
Mechanical durability is 8000 cycles; electrical durability is 1000 cycles in AC-23A/B and 200 cycles in DC-23A/B. The operating temperature range is -4 to 158 °F (-20 to 70 °C), with protective treatment TH (tropicalization) for humid environments. IP20 with terminal cover per IEC 60529 — finger-safe but not sealed against water ingress, so it belongs in a cabinet or enclosure.