MCCB for line protection — 40 A, 3-pole, with undervoltage release
The Siemens 3VA1140-5EF32-0BA0 is a SENTRON 3VA1 molded case circuit breaker (MCCB) rated 40 A at 40 °C, with three poles and a built-in undervoltage release (UVR). It is designed for line protection — meaning it guards the feeder or branch circuit against overloads and short circuits, not a specific motor or load. The UVR trips the breaker when control voltage drops below a set threshold, which is standard for emergency-stop circuits or undervoltage protection schemes in industrial panels.
Breaking capacity — what the ratings mean for your fault-current study
This MCCB carries a 187 kA interrupting rating at 240 VAC — that is its highest published breaking capacity, typical for a high-interrupting 3VA1 frame at low voltage. At 415 VAC it is rated 121 kA; at 440 VAC, 75.6 kA; at 500 V and 690 VAC, 17 kA. These are the maximum fault currents the breaker can safely clear at each voltage level. For a panel designer, the relevant number is the one matching your system voltage and available fault current — the 187 kA figure at 240 V is not usable at 480 V, where the 17 kA rating governs. The rated insulation voltage is 800 V, so the breaker is rated for 480/277 V and 600 V systems within its published interrupting limits.
Thermal-magnetic trip — TM240, no communication, no ground-fault
The overcurrent release is a TM240 — a fixed thermal-magnetic trip unit. That means the thermal element handles overloads (inverse time) and the magnetic element handles short circuits (instantaneous). There is no electronic adjustment, no communication function, and no ground-fault monitoring on this variant. The power loss is 13.3 W maximum, which matters for thermal management inside a sealed enclosure. Ambient temperature derating starts above 55 °C: at 55 °C the rating drops to 39 A, at 65 °C to 38 A, and at 70 °C to 37 A. Below 55 °C the breaker is rated a full 40 A.
Panel fit — dimensions and mounting
The breaker measures 70 mm deep, 76.2 mm wide, and 130 mm high. It is a 3-pole MCCB designed for DIN-rail or direct-panel mounting in a distribution board or motor control center. The 76.2 mm width (3 inches) is standard for a 3-pole SENTRON 3VA1 frame, so it occupies a predictable footprint in a multi-breaker lineup. No auxiliary contacts or shunt trip are included on this order code — only the undervoltage release.