What it is and what the ratings mean
The Siemens SENTRON 3VA1120-5EF32-0AE0 is a 3-pole molded case circuit breaker (MCCB) for line protection, carrying a rated continuous current Iu of 20 A and a rated insulation voltage Ui of 800 V. The TM240 overcurrent release is fixed (no adjustable thermal or magnetic settings), so what you see on the nameplate is what you get — no dials to mis-set on site. The breaker holds 20 A up to 50 °C ambient; above that it derates stepwise to 18 A at 70 °C, which matters if this lives in a hot panel next to transformers or drives. Breaking capacity is the headline here: 187 kA at 240 V, 121 kA at 415 V, 75.6 kA at 440 V, and 17 kA at 690 V. That 187 kA figure means it can safely interrupt a fault current up to that level at 240 V without welding contacts or rupturing the case — a useful margin for high-available-fault panels feeding motor control centers or distribution boards.
Panel fit and auxiliary contacts
The breaker is 76.2 mm wide, 130 mm tall, and 70 mm deep — that's roughly 3 inches wide, so it fills three 18 mm pole spaces on a DIN rail or panel-mount plate. The front face carries an IP40 rating, meaning it's protected against tools and wires >1 mm but not against water spray; keep it behind a gland plate or enclosure door in washdown areas. It ships with four HQ auxiliary switches (form C / changeover contacts) already installed — no add-on kit needed. That gives you status feedback for PLC inputs, alarm annunciation, or interlocking without cracking the cover. No undervoltage release, no shunt trip, no ground-fault module on this variant, so if you need those, this isn't the order code for that.
Lifecycle and sourcing reality
Pricing and availability change weekly; we quote firm numbers against an RFQ. If you need a drop-in for a panel originally built around the 3VA1010-2ED32-0JA0, check the width — the 3VA1120 is 76.2 mm wide versus the 3VA1010's narrower frame, so it may not fit the same mounting hole pattern or bus bar spacing. Measure first.