What this MCCB is and what the ratings mean for fit
The Siemens 3VA1150-6EF36-0AH0 is a SENTRON molded case circuit breaker (MCCB) with three poles, a rated continuous current Iu of 50 A, and a TM240 thermal-magnetic overcurrent release. The TM240 designation means the thermal trip is fixed at 240 A frame rating, with the magnetic pickup set to the standard band — this is a line-protection device, not a motor-protection piece, so it's sized for feeder or distribution duty where you need short-circuit and overload protection on a cable or bus. Breaking capacity is the headline number that decides whether this breaker clears a fault without welding its contacts or venting arc gas into the panel. At 240 V it's rated 220 kA; at 415 V it's 154 kA; at 440 V it's 121 kA; at 690 V it's 17 kA. That's a very high interrupting rating for the 50 A frame — it tells you this breaker is designed for high-fault-current installations, typically downstream of a large transformer or in a switchboard where the available fault current is well above what a standard 25 kA or 50 kA MCCB could handle. The continuous current rating holds at 50 A up to 50 °C ambient. At 55 °C it derates to 48 A, at 60 °C to 47 A, at 65 °C to 46 A, and at 70 °C to 45 A. If your panel runs hot — say a non-ventilated enclosure near a furnace line or in a Middle East summer — you need to check the actual ambient at the breaker location, not the room setpoint, because the 50 A nameplate only applies below 50 °C.
Auxiliary contacts and trip indication
This version ships with 2 auxiliary switches plus 1 trip alarm switch, designated HQ. The trip alarm switch changes state only when the breaker trips on fault — not on manual open — so you can wire it to a PLC input or alarm beacon to distinguish a deliberate shutdown from a fault event. That's useful for remote monitoring or for a maintenance team that needs to know whether to look for a short or just a scheduled isolation.
Panel integration — dimensions and mounting
The breaker measures 130 mm high, 76.2 mm wide, and 70 mm deep. Front protection is IP40 — suitable for a clean indoor panel, but not for washdown or outdoor installation without an additional enclosure. The operating temperature range is -25 °C to 70 °C; storage range is -40 °C to 80 °C.