SENTRON 3VA1120-3GF46-0AA0 — 20 A MCCB for Line Protection
The Siemens 3VA1120-3GF46-0AA0 is a SENTRON molded case circuit breaker (MCCB) configured for line protection, rated 20 A continuous current (Iu) with a 4-pole design. It carries a TM240 thermal-magnetic overcurrent release, meaning the thermal element is fixed at 20 A while the magnetic short-circuit pickup is adjustable up to 320 A (li max). This is the breaker you spec when the branch needs a dedicated 4-pole disconnect with adjustable instantaneous trip — typical for feeder circuits in distribution panels where you need to coordinate downstream with upstream devices.
Interrupting Capacity by Voltage Level
Interrupting capacity varies significantly with system voltage: 75.6 kA at 240 V, 52.5 kA at 415 V, 32 kA at 440 V, and 11.9 kA at both 500 V and 690 V. At 240 V the 75.6 kA figure gives substantial headroom for high-fault industrial services; at 690 V the 11.9 kA still covers most standard distribution transformer secondary faults. The rated insulation voltage (Ui) is 800 V, and the maximum operational DC voltage is 600 V — so this breaker can also serve DC bus applications within those limits.
Thermal Derating and Panel Integration
The breaker holds its full 20 A rating from 45 °C through 55 °C ambient; at 60 °C it derates to 19 A, and holds there through 70 °C. That means in a warm panel — say 55 °C internal ambient — you still get the full 20 A without derating. The front face carries IP40 protection, so it's suited for enclosed distribution boards where tools or fingers won't contact live parts. Dimensions are 130 mm height, 101.6 mm width, 70 mm depth — fits standard 4-pole MCCB mounting footprints in SENTRON panelboards. Maximum power loss is 12 W, which matters for thermal budgeting in sealed enclosures.