What this MCCB delivers — and where the ratings matter
The Siemens 3VA1110-3FF42-0AA0 is a 4-pole SENTRON molded case circuit breaker rated for 100 A continuous current (Iu) with a TM240 thermal-magnetic release — meaning the thermal element is fixed at 100 A and the magnetic pickup is set at 240 A, a common combination for feeder or distribution protection where you want a wide margin between full-load current and short-circuit trip threshold. Breaking capacity is the headline number that decides whether this breaker holds under fault: 76 kA at 240 V AC, 53 kA at 415 V, 32 kA at 440 V, and 11.9 kA at both 500 V and 690 V. At 690 V the 11.9 kA figure means it's suited for industrial systems where the available fault current stays under that threshold — typical for a 690 V distribution board behind a step-down transformer. The 76 kA at 240 V gives headroom for high-fault panels close to the service entrance. Thermal derating is gradual: holds 100 A up to 50 °C ambient, then drops to 98 A at 55 °C, 96 A at 60 °C, 94 A at 65 °C, and 91 A at 70 °C. If the panel runs hot — say near a furnace line or in a sealed enclosure — you need to account for that 9 A drop at the top end. The rated insulation voltage is 800 V, and the maximum DC operational voltage is 600 V, so it covers both AC and DC distribution in the same footprint.
Lifecycle and sourcing posture — active, not a legacy hunt
For a maintenance spares buyer, this is the kind of breaker you keep one in the cabinet for — it's a common 100 A 4-pole frame that backs up dozens of panel builds. The endurance rating of 20 000 operations (mechanical) gives a reasonable service life for a distribution breaker that sees infrequent switching.
Panel fit and integration notes
Dimensions are 101.6 mm wide, 130 mm high, 70 mm deep — the 101.6 mm width is a standard 4-pole MCCB footprint (about 4 inches), so it drops into a DIN-rail or panel-mount base without surprises. The front face carries an IP40 protection rating, meaning it's protected against tools and wires >1 mm but not against water ingress — keep it inside a rated enclosure. No communication module on this version; it's a straight electromechanical breaker with no integrated metering or fieldbus. The N-conductor protection is designed at 50% of the phase rating, which is typical for 4-pole breakers in TN or TT systems where the neutral is not fully rated. Power loss is a maximum of 25 W — relevant for thermal calculations inside a sealed enclosure with multiple breakers side by side.