What this breaker is and what it does
The Siemens SENTRON 3VA1040-4ED36-0AA0 is a 3-pole molded case circuit breaker (MCCB) rated for 40 A continuous current, designed for line protection in distribution panels. It uses a TM210 thermal-magnetic overcurrent release — the thermal element handles overloads, the magnetic element handles short-circuits. No undervoltage release, no ground-fault monitoring, no communication module on this variant; it is a straight thermal-magnetic breaker for basic feeder or branch protection.
Breaking capacity — what the ratings mean for fit
This breaker delivers 121 kA breaking capacity at 240 V, dropping to 75.6 kA at 415 V, 52.5 kA at 440 V, and 11.9 kA at both 500 V and 690 V. Those are the maximum fault currents it can safely interrupt at each voltage level. For a 480 V panel (common in North America), the relevant figure is the 440 V rating — 52.5 kA — which is the closest standard voltage below 480 V in the table. The 690 V rating (11.9 kA) tells you this MCCB can also serve 600 V class systems where available fault current stays under that threshold.
Thermal derating — when 40 A is not 40 A
The 40 A continuous rating holds from 40 °C to 50 °C ambient. At 55 °C it derates to 39 A, at 65 °C to 38 A, and at 70 °C to 37 A. If this breaker sits in a crowded, poorly ventilated enclosure where internal air temperature hits 60 °C, you lose 1 A of headroom — plan your load at 39 A max, not 40. The insulation voltage rating is 800 V, which covers most low-voltage distribution networks up to 690 V phase-to-phase.
Panel fit and dimensions
The breaker measures 130 mm high, 76.2 mm wide, and 70 mm deep — a standard 3-pole MCCB footprint that fits most DIN-rail or panel-mount enclosures. The 76.2 mm width (3 inches) means three of these sit in a 9-inch wide section. Power loss at rated current is 10.8 W maximum; account for that heat in the enclosure thermal calculation, especially when grouping multiple breakers.