What this MCCB is and what it does
The Siemens 3VA1020-4ED32-0BA0 is a SENTRON molded case circuit breaker (MCCB) rated for line protection — it sits between the transformer or main bus and a branch circuit, ready to clear a fault before the damage spreads. Three poles, 20 A continuous at 40 °C through 55 °C, and it holds the same 20 A all the way up to 55 °C before it starts to derate: at 60 °C it's 19 A, at 65 °C it's 19 A, and at 70 °C it's 19 A. That's a solid thermal curve for a panel that runs warm — you don't lose headroom until you're past 55 °C. The overcurrent release is a TM210 — a thermal-magnetic type, fixed at 20 A, no electronic adjustment. That means the trip curve is set at the factory: thermal for overloads, magnetic for short-circuits. No dip switches, no dials, no confusion on a panel rebuild. The auxiliary release fitted is an undervoltage release (UVR), so if the control voltage drops below its dropout threshold the breaker opens — common on machine safety circuits where a loss of control power should kill the load. Breaking capacity is where this breaker earns its keep in a high-fault panel. At 240 V it interrupts 121 kA; at 415 V it's 75.6 kA; at 440 V it's 52.5 kA; at 500 V and 690 V it's 11.9 kA. That 121 kA at 240 V tells you this is built for a location with a big transformer close by — a main or a feeder breaker in a heavy industrial plant, not a sub-panel in an office.
Mounting and panel fit
The 3VA1020-4ED32-0BA0 measures 70 mm deep, 76.2 mm wide, and 130 mm tall. That 76.2 mm width — exactly 3 inches — is the standard 3-pole MCCB footprint for the SENTRON 3VA platform. It mounts on a DIN rail or directly to a backplate via screw terminals. The 70 mm depth means it clears most standard enclosure depths; check your gland plate clearance if the panel is shallow.
Sourcing and lifecycle
The 3VA1020-4ED32-0BA0 is the line-protection variant with an undervoltage release. If your BOM calls for this exact code, the TM210 release and the UVR are the two features that lock the fit — a 3VA part with a different release or without the UVR won't drop in without rewiring the control circuit.