The Siemens 3VA1225-6GF42-0JA0 is a 4-pole IEC molded-case circuit breaker on the 250 A frame, built for line protection in distribution panels and motor control centers. Its class H breaking capacity — Icu=70 kA at 415 V — means it can safely interrupt a fault current up to that level without welding its contacts or cascading failure upstream. That rating drives the SCCR (short-circuit current rating) for the entire panel downstream, so it is the number the site electrical engineer checks first when coordinating selectivity with the main breaker.
Overload and short-circuit protection settings
The TM240 thermal-magnetic trip unit gives an In=250 A continuous rating. Overload protection (Ir) is adjustable from 175 A to 250 A via the ATAM dial, so a single breaker frame covers a range of feeder sizes — a 200 A motor branch today, a 225 A feeder next quarter. Short-circuit magnetic pickup (Ii) is set at 5 to 10 times In, meaning the instantaneous trip fires between 1250 A and 2500 A. That band lets the panel builder tune coordination with downstream branch breakers without swapping trip units.
Integrated shunt trip and neutral protection
The factory-fitted shunt trip (STL) operates on 110-127 V DC or AC 50/60 Hz — a remote-trip coil for emergency-stop circuits or supervisory control. The N-conductor protection is set at 100%, so the neutral pole tracks the phase poles. The nut keeper kit is included, which saves the panel OEM a separate fastener order and prevents loose terminations on a 250 A lug.