What this MCCB is and where it lands
The Siemens SENTRON 3VA1140-5ED12-0AA0 is a 1-pole molded case circuit breaker (MCCB) rated for line protection. It carries a continuous current rating of 40 A at 45 °C, derating to 37 A at 70 °C. The interrupting rating hits 121 kA at 240 V AC — that is the headline number for high-fault panels — and 9 kA at 415 V AC. The TM210 thermal-magnetic release provides LI protection (long-time and instantaneous), with a fixed instantaneous trip at 400 A.
What the ratings mean for fit
The 121 kA at 240 V is the SCCR (short-circuit current rating) — it means this breaker can safely interrupt a fault up to that level without welding contacts or venting plasma, critical for main-service or high-fault panels where available fault current is high. The 9 kA at 415 V is the three-phase rating; if your panel runs 415 V three-wire delta, that is the number that governs coordination. The 40 A continuous rating holds at 45 °C and 50 °C, then drops 1 A per 5 °C step above 55 °C — a standard thermal derating curve that matters if the breaker sits in a warm enclosure or next to other heat sources. The TM210 release is a thermal-magnetic design: the thermal element handles overloads (long-time), the magnetic element handles short-circuits (instantaneous). The fixed instantaneous pickup at 400 A (10× In) is typical for a line-protection MCCB — it clears hard faults fast without nuisance tripping on motor inrush. The LI protection function means no ground-fault or short-delay element; this is a straightforward branch-circuit breaker, not a main with selective coordination.
Physical fit and panel integration
The 1-pole chassis measures 25.4 mm wide (1 inch), 130 mm tall, 70 mm deep. That is a standard MCCB footprint for a 1-pole unit — mounts on a DIN rail or direct-panel plate. The IP40 front protection means it is splash-proof from the front but not sealed; suitable for indoor panels, not washdown zones. No auxiliary contacts or motor drive fitted on this variant (0 CO contacts, no motor drive option).