The 187 kA at 240 V tells you this breaker is sized for the high-end of SCCR requirements on 240 V delta or 240/120 V center-tapped services. Drop to 415 V and it still holds 121 kA; at 440 V it's 75.6 kA; at 500 V and 690 V it holds 17 kA. That curve means the breaker clears fast enough to protect downstream gear across a wide voltage range without cascading failure — useful when the same panel feeds both 480 V and 240 V loads through separate transformers. The 20 A rating holds flat from 40 °C through 55 °C, then derates to 19 A at 60–70 °C — no surprise for a thermal-magnetic MCCB, but worth noting if the breaker lives in a hot enclosure next to a transformer or drive.
Auxiliary and shunt trip fit
The shunt trip lets a remote signal — from an E-stop, fire alarm relay, or PLC output — open the breaker electrically without a person at the handle. No undervoltage release on this code; if UVR is required, that's a different suffix. The auxiliary switches are designated HQ type — that's Siemens' notation for early-make / late-break contacts used in signaling circuits. They mount on the left side of the breaker and are wired through the terminal cover. The shunt trip coil draws from the control voltage; verify polarity and voltage rating against the panel's control transformer before wiring.
Maximum power loss is 12 W at rated load. That's moderate for a 20 A MCCB; in a dense panel with multiple breakers side-by-side, account for the cumulative heat in the enclosure sizing calculation.