The Siemens SENTRON 3VA1112-6EF36-0JA0 is a 3-pole molded case circuit breaker (MCCB) rated 125 A at 40 °C, with a TM240 thermal-magnetic overcurrent release and an integrated shunt trip (STL) auxiliary release. Its 220 kA breaking capacity at 240 V AC makes it a strong candidate for high-fault distribution boards where upstream transformer capacity or parallel-fed buswork pushes available fault current well above typical 65 kA or 100 kA MCCB ratings.
Breaking capacity and thermal derating
Breaking capacity steps down with voltage: 220 kA at 240 V, 154 kA at 415 V, 75.6 kA at 440 V, and 17 kA at both 500 V and 690 V. That 17 kA at 690 V is the figure to check if the breaker lands in a 690 V distribution section — it's adequate for most industrial 690 V panelboards but not for high-fault 690 V buswork. The TM240 release holds 125 A flat from 40 °C through 50 °C, then derates to 122 A at 55 °C, 120 A at 60 °C, 117 A at 65 °C, and 114 A at 70 °C. For a panel running at 55 °C ambient, the usable rating drops to 122 A — plan the load accordingly.
Shunt trip and line-protection design
The shunt trip (STL) auxiliary release allows remote tripping via a control voltage — useful for emergency-stop circuits or supervisory shutdown schemes where the MCCB must open on a signal from a fire alarm, PLC, or safety relay. The breaker is designed for line protection (cable and busbar protection), not motor protection — the TM240 curve is thermal-magnetic, not electronic, so it suits distribution feeders and branch circuits feeding downstream subpanels or fixed loads. No undervoltage release, no ground-fault monitoring, no communication function on this variant.
Physical fit and panel integration
At 70 mm deep, 76.2 mm wide, and 130 mm tall, this 3-pole MCCB fits standard Siemens 3VA mounting accessories and busbar systems. The 76.2 mm width (3 inches) matches the typical 3-pole MCCB footprint for DIN-rail or backplate mounting. Depth of 70 mm leaves enough clearance for rear-connected busbars in a 200 mm deep enclosure. Max power loss of 28.1 W means the breaker dissipates heat into the enclosure — account for it in the panel thermal budget, especially if multiple breakers are ganged.