What this MCCB carries — and why the ratings matter for your panel
The Siemens 3VA2463-5JQ32-0KH0 is a 3-pole SENTRON molded case circuit breaker rated 630 A continuous at 40 °C, with a maximum breaking capacity of 187 kA at 240 V AC. That 187 kA figure drops to 121 kA at 415/440 V and to 17 kA at 690 V — so the voltage on your line determines whether this breaker handles a high-fault service entrance or a downstream feeder. The thermal derating curve runs from 630 A at 40 °C down to 450 A at 70 °C; if your enclosure runs hot, size for the actual ambient, not the nameplate. The electronic trip unit is an ETU560, which gives you adjustable long-time, short-time, instantaneous, and ground-fault protection. The ground-fault monitoring uses summation current formation on the L-conductor — it sums the phase currents and trips on imbalance, not a separate neutral CT. That matters when you're retrofitting into a panel that doesn't have a dedicated ground-fault sensor. Power loss hits 162 W maximum at rated load. In a densely packed enclosure, that heat has to move — leave breathing room around the breaker or factor in forced ventilation.
Auxiliaries and integration — what's built in, what's not
This order code comes with a factory-fitted shunt trip (STL) release and a 2+1 auxiliary contact block — two auxiliary switches plus one trip alarm switch (HQ designation). The shunt trip lets you remotely trip the breaker from a PLC or emergency-stop circuit; the trip alarm switch signals an overcurrent or ground-fault event back to the control system. The breaker is 138 mm wide, 248 mm tall, and 110 mm deep. That 138 mm width is a fixed 3-pole frame — it occupies three adjacent mounting slots on the panel backplate. The depth of 110 mm means it clears most standard enclosure depths, but check your door clearance if you're mounting a rotary handle or motor operator on the front. Communication function is included on this variant, though the evidence doesn't specify the protocol — expect PROFIBUS, PROFINET, or Modbus depending on the communication module ordered separately. The base breaker has the slot and wiring harness ready.
Lifecycle and sourcing reality
Because this is a current-production part with multiple configurable options (trip unit, auxiliaries, communication), the exact order code you see is the one you need to quote. The base switch is 3VA2463-5JQ32-0AA0; the -0KH0 suffix adds the shunt trip, the 2+1 auxiliary block, and the communication-ready build. No field retrofitting required.
Selectivity and coordination — where this breaker fits
At 630 A frame size, this MCCB is typically a main or large feeder breaker in a 480 V or 600 V distribution panel. The 187 kA interrupting rating at 240 V makes it suitable for service-entrance applications on the low-voltage side of a transformer; the 121 kA at 415 V covers most industrial 400 V-class systems. The 17 kA at 690 V is enough for 690 V drives and motors but not for high-fault 690 V utility connections. The latching endurance is rated at 15,000 operations — that's mechanical, not electrical. For frequent switching duty, factor in the electrical endurance curve (not listed here) which will be lower at full load. This breaker is designed for infrequent switching and protection, not as a motor-starting contactor.