What it is and what it does
This is a Siemens 3VA1 IEC frame 160 circuit breaker, order code 3VA1150-3GF42-0AA0-ZD00, configured as a 4-pole line protection device with a TM240 thermal-magnetic trip unit. The ATAM designation means it's an adjustable thermal, adjustable magnetic — so you set the overload protection anywhere from 35 A to 50 A (Ir) and the short-circuit pickup between 5 and 10 times In (Ii). The 25 kA Icu at 415 V puts it in breaking capacity class N, which is the standard duty class for general distribution panels where fault levels are moderate. The N-conductor protection is set to 100%, meaning the neutral pole is fully protected at the same rating as the phase poles — important for 4-wire systems where neutral current can approach phase current.
What the ratings mean for fit
The In=50 A rating with an adjustable Ir range of 35 A to 50 A means this breaker covers a motor or feeder load that draws between those values. You dial in the exact continuous current with the thermal adjustment, so one breaker body covers a range of load sizes — good for stocking flexibility. The Ii adjustment from 5x to 10x In (250 A to 500 A) lets you tune the magnetic pickup to avoid nuisance trips on inrush while still clearing a hard fault. The 4-pole construction with 100% N protection means it's suited for 3-phase + neutral distribution where the neutral is not just a reference but carries load current — common in commercial and light industrial panels. The IEC frame 160 footprint is standard for Siemens 3VA1 accessories and busbar systems.