Siemens SENTRON 3VA1020-4ED36-0AC0 — 20 A MCCB with 121 kA SCCR
The Siemens SENTRON 3VA1020-4ED36-0AC0 is a 3-pole molded case circuit breaker (MCCB) rated for line protection, carrying a continuous current of 20 A across the 40 °C to 55 °C ambient range and derating to 19 A at 70 °C. Its headline interrupting capacity hits 121 kA at 240 V AC — that is the figure that governs fault-clearing capability in high-fault panels, not the lower 75.6 kA at 415 V or 52.5 kA at 440 V. For a 20 A frame, 121 kA SCCR means this breaker can safely interrupt a fault up to that level without upstream cascading, which is the deciding spec when coordinating with a transformer or generator bus. The TM210 overcurrent release is a thermal-magnetic design — thermal element handles overloads, magnetic element handles short-circuits. No undervoltage release, no voltage trigger, no communication function, and no ground-fault monitoring on this variant. The basic switch code is 3VA10204ED360AA0, and the auxiliary switch complement is two HQ-type switches. Rated insulation voltage is 800 V, so the breaker is suitable for 690 V line-to-line systems common in European and Asian industrial networks. Maximum power loss is 12 W at rated load — a figure to factor into enclosure thermal calculations when grouping multiple breakers in a panel.
Integration and Mounting
Dimensions: 130 mm height, 76.2 mm width, 70 mm depth. The 3-pole footprint fits standard Siemens SENTRON panel-mounting patterns; no DIN-rail adapter is required for the base unit. The auxiliary switches HQ are factory-installed, so no field-assembly of add-on blocks is needed for basic signaling. Operating temperature range is -25 °C to 70 °C, storage from -40 °C to 80 °C. The 12 W maximum power loss at full load should be considered when sizing enclosure ventilation — at 20 A continuous, the thermal dissipation is modest but not negligible in a sealed cabinet.
Interrupting Capacity Breakdown
The 121 kA at 240 V is the peak interrupting rating; at 415 V it drops to 75.6 kA, at 440 V to 52.5 kA, and at 500 V and 690 V it holds at 11.9 kA. This is a typical curve for a high-interrupting MCCB — the 240 V rating is what drives selectivity in North American 277/480 V panels where the line-to-neutral fault current can be high. For 690 V systems, the 11.9 kA limit means the breaker is best suited for downstream distribution rather than main service entrance at that voltage.