MCCB for line protection — 100 A, three-pole, high interrupting capacity
Interrupting ratings — where the headroom lives
At 240 V the breaker holds 187 kA symmetrical; at 415 V it's still 121 kA. Drop to 500 V and it's 75.6 kA; at 690 V it falls to 3.7 kA (–). That steep derate above 500 V is typical for an air-break MCCB — the arc doesn't extinguish as readily at higher voltage. For a 400 V line-to-line panel, the 121 kA figure gives you generous selectivity headroom against a 50 kA or 65 kA available fault current.
Auxiliary switching and trip indication
The auxiliary switch signals the breaker's open/closed position to a PLC or status lamp; the trip alarm switch closes only when the breaker has tripped on fault, not on manual open — useful for a remote alarm that distinguishes a maintenance shutdown from a real event. The basic switch is order code 3VA21105HN320AA0, which is the internal mechanism; if you're replacing just that subassembly, that's the number to cross-reference.