SENTRON 3VA1150-5EF32-0BA0 — 50 A MCCB with TM240 release
The Siemens SENTRON 3VA1150-5EF32-0BA0 is a 3-pole molded case circuit breaker rated for 50 A continuous current (Iu) with a TM240 thermal-magnetic overcurrent release. Its 187 kA breaking capacity at 240 V AC means it can safely interrupt very high fault currents on the low-voltage side of a distribution transformer. The 800 V rated insulation voltage (Ui) gives headroom for systems without derating the insulation path. The TM240 release provides fixed thermal and magnetic trip settings tuned for line protection (cable and busbar), not motor overload curves. This breaker is designed for distribution panelboards and switchboards where selectivity with downstream breakers is planned. The undervoltage release (UVR) integrated as standard allows remote or automatic tripping when control voltage drops — useful for emergency-stop circuits or undervoltage protection schemes.
Breaking capacity across voltages
Rated short-circuit breaking capacity varies with system voltage: 187 kA at 240 V AC, 121 kA at 415 V AC, 75.6 kA at 440 V AC, and 17 kA at 690 V AC. At 415 V, the 121 kA rating covers most industrial and commercial distribution applications where transformer impedance limits fault current to around 50–65 kA — this breaker provides substantial margin. The 690 V rating at 17 kA is adequate for 690 V drives or mining distribution but note the drop-off.
Thermal derating and operating range
Rated current holds at 50 A from 40 °C up to 50 °C ambient. Derating starts at 55 °C (48 A), stepping down to 45 A at 70 °C. This is a flat curve through 50 °C — useful for panels with moderate internal heat rise. Operating temperature range is -25 °C to +70 °C; storage range is -40 °C to +80 °C. The IP40 front protection means the breaker face is protected against tools and small wires but not water — install in a suitable enclosure for washdown or outdoor environments.
Physical fit and mounting
Dimensions: 130 mm height, 76.2 mm width, 70 mm depth. The 76.2 mm width (3-inch footprint) is standard for 3-pole SENTRON 3VA molded case breakers in this frame size — it fits existing panel cutouts and busbar spacing for 3-pole distribution. The 70 mm depth is shallower than many competitive MCCBs, leaving more wiring space behind the breaker in a 600 mm deep enclosure.
Undervoltage release and auxiliary options
This variant includes an undervoltage release (UVR) as the auxiliary release — part number 3VA9608-0BB11 for the integrated trip unit. No auxiliary contact version is fitted (without). No communication function, no voltage trigger, no ground fault monitoring. The UVR trips the breaker when control voltage drops below a threshold — typically wired to an emergency stop or undervoltage relay. If you need auxiliary contacts for status feedback, they must be added as a separate accessory.