What this MCCB is and what it does
The Siemens 3VA1180-5MH36-0AA0 is a 3-pole SENTRON molded case circuit breaker (MCCB) designed specifically for starter protection — meaning it's built to protect motor starters and their associated wiring from overloads and short circuits, not just general distribution loads. It carries an 80 A rating at 40 °C ambient (derated to 74 A at 70 °C) and uses a TM120M thermal-magnetic overcurrent release: the thermal element handles overloads, the magnetic element handles short-circuit trips. The insulation voltage is rated 800 V, so it's comfortable on 400/480 V line-to-line systems common in industrial panels. Breaking capacity is the headline spec here: 187 kA at 240 V AC, 121 kA at 415 V, 75.6 kA at 440 V, and still 7.5 kA at 690 V. That 187 kA figure at 240 V means it can safely interrupt a fault current up to 187,000 amps — useful on high-capacity transformer secondaries or busway taps where available fault current is extreme. The 7.5 kA at 690 V is still respectable for a 3-pole breaker on 690 V line-to-line systems (common in mining or marine).
Panel fit and thermal management
The 3VA1180-5MH36-0AA0 measures 130 mm high, 76.2 mm wide, and 70 mm deep — a 3-pole MCCB footprint that fits standard Siemens 3VA panel mounting. The IP40 rating on the front means it's protected against solid objects over 1 mm (tools, wires) but not sealed against moisture; mount in a clean, dry enclosure or behind a panel door. Maximum power loss is 19.2 W — that heat has to be dissipated inside the enclosure, so factor it into your thermal budget if you're stacking multiple breakers in a sealed cabinet. Operating temperature range is -25 °C to +70 °C, storage from -40 °C to +80 °C. The 80 A rating holds flat from 40 °C to 50 °C, then derates gradually to 74 A at 70 °C. If your panel ambient runs above 50 °C, you'll need to account for that 6 A derate in your load calculation.
What the TM120M release means for your motor circuit
The TM120M designation tells you the thermal-magnetic release has a fixed thermal pickup of 80 A (the '120' refers to the frame size, not the amp setting) and a magnetic trip that's adjustable or fixed depending on the variant — on this order code it's a factory-set unit. For starter protection, the TM120M provides the coordinated overload and short-circuit protection that a motor starter needs, without relying on an external relay. The 3VA1180-5MH36-0AA0 has no undervoltage release, no voltage trigger, no trip indicator, and no communication function — it's a straight electromechanical breaker with no auxiliary electronics.