500 A MCCB with TM220 release — what the ratings mean for your panel
The Siemens SENTRON 3VM1450-5EE32-0AA0 is a 3-pole molded case circuit breaker (MCCB) rated for line protection, carrying a continuous current of 500 A across the 40 °C to 50 °C band without derating. At 55 °C it holds 488 A, at 60 °C it holds 476 A, and at 65 °C it holds 464 A — the thermal curve is published, so you can size it for elevated ambient inside a closed panel without guessing. The TM220 designation means a thermal-magnetic overcurrent release — the thermal element handles overload protection (time-delayed, inversely proportional to current), and the magnetic element handles instantaneous short-circuit response. No ground-fault monitoring, no undervoltage release, no communication function on this variant: it is a straight feeder or main breaker for a distribution panel where upstream coordination and downstream selectivity are handled by the trip curve alone. Breaking capacity is spec'ed per voltage: 187 kA at 240 V AC, 121 kA at both 415 V and 440 V AC, and 76 kA at 500 V AC. The rated insulation voltage is 800 V, and the maximum operating voltage is 690 V AC. For a 500 A frame, these interrupting ratings put it in the high-fault-current class — suitable for service-entrance or large subfeed applications where the available fault current is substantial. Physical footprint: 138 mm wide, 248 mm tall, 110 mm deep. IP40 protection on the front face only — the body is not sealed against dust ingress, so it belongs inside a panel, not in a washdown zone. Operating temperature range is -25 °C to 70 °C; storage range is -40 °C to 80 °C. Maximum power dissipation is 123 W at rated load — factor that into your enclosure thermal calculation.