The Siemens 5SJ4130-7XX40 is a 1-pole miniature circuit breaker rated 30 A with a C-trip curve, 10 kA interrupting capacity, and UL 489 listing at 277 V. That 10 kA SCCR means it can safely interrupt a fault current up to 10,000 A without welding contacts or cascading failure upstream — critical for panel coordination in a 277/480 V distribution board. The C-curve (5–10× In) handles motor inrush and lighting ballast loads without nuisance tripping on start-up.
The 1-pole footprint takes one 18 mm module width. UL 489 listing means it's accepted as a branch-circuit protective device in North American panels; the same breaker carries IEC ratings for global projects, so one part number covers both UL and IEC BOM lines.