What it is and what it does
The Siemens 3VA1340-6EF32-0AA0-ZD00 is a 3-pole IEC frame 400 molded-case circuit breaker (MCCB) from the 3VA1 series, built for line protection in industrial distribution panels. Its headline rating is a breaking capacity class H Icu=70kA at 415 V — that means it can safely interrupt fault currents up to 70 kA without damage to itself or upstream gear, which is the figure that governs your SCCR coordination downstream.
Overload and short-circuit settings
The TM240 ATAM trip unit gives you an adjustable overload protection range Ir=280 A to 400 A (the In=400 A rating), so you dial in the exact continuous current for your load — a 300 A feeder gets Ir=300 A, not a fixed value. Short-circuit protection Ii is adjustable from 5 to 10 times In, meaning 2000 A to 4000 A magnetic pickup. That range lets you ride through motor inrush on a pump or conveyor without nuisance tripping, while still clearing a hard fault.