In a 50 °C panel, you'd need to apply the manufacturer's thermal derating curve — the 100 A figure is the starting point, not the ceiling for all conditions. The LSIG protection set gives you four independently adjustable curves: long-time pickup (Ir) adjustable 40–100 A, short-time pickup (Isd) with 9 settings, instantaneous (Ii) adjustable, and ground-fault (Ig) adjustable. The 20-minute thermal memory before and after tripping means the trip unit remembers prior heating events, so a reclose after a near-trip won't let the conductor overheat on the second hit — critical for motor feeders or cyclic loads. Zone selective interlocking (ZSI) is built in. On a multi-level distribution system, ZSI lets downstream breakers trip instantly on a fault while upstream breakers hold their delay — keeps the fault isolated to the smallest zone. Without ZSI, the upstream breaker would wait out its full delay, exposing more of the bus to the fault current.
Deployment context
This trip unit mounts into a ComPacT NSX100...250 fixed or plug-in circuit breaker frame. The 4-pole configuration with neutral on the left is standard for 3-phase + N distribution panels. IP40 front-of-panel protection means it's suitable for indoor switchboards and distribution boards — not for washdown or outdoor enclosures without additional cabinet sealing.