What this MCCB carries — and where it fits
The Siemens 3VA1120-5EF36-0AG0 is a 3-pole SENTRON molded case circuit breaker rated for 20 A continuous current (Iu) with a TM240 thermal-magnetic overcurrent release. It's built for line protection — no undervoltage release, no ground-fault monitoring, no communication module. The interrupting capacity tells the story: 187 kA at 240 V, 121 kA at 415 V, 75.6 kA at 440 V, and 17 kA at 690 V. That's a high-interrupting frame sized for main feeders or large sub-distribution where fault current is serious. The TM240 release is fixed, not adjustable — set it and forget it. The breaker carries a 1 auxiliary switch plus 1 trip alarm switch (HP type) for status feedback to a PLC or annunciator panel. Mechanical endurance is rated at 15 000 operations, which is standard for this class of distribution breaker.
Thermal derating and panel fit
The 20 A rating holds flat from 40 °C through 50 °C. Above that, it steps down: 19.2 A at 55 °C, 18.8 A at 60 °C, 18.4 A at 65 °C, 18 A at 70 °C. If the panel ambient runs hot, size the load accordingly — don't count on the full 20 A above 50 °C. Operating temperature range is -25 °C to 70 °C; storage range is -40 °C to 80 °C. Dimensions: 130 mm high, 76.2 mm wide, 70 mm deep. The 76.2 mm width is a 3-pole frame that fits standard SENTRON panel mounting. IP40 on the front — protected against tools and small wires, but not washdown. This is a dry-switchgear enclosure part.