630 A MCCB with ETU550 — what the ratings mean for your panel
The Siemens SENTRON 3VA2463-5JP32-0DC0 is a 3-pole molded case circuit breaker rated for 630 A continuous current (Iu) at 40 °C, with an ETU550 electronic trip unit that gives you adjustable long-time, short-time, instantaneous, and ground-fault protection curves. That 630 A figure is the thermal base — at 45 °C it derates to 600 A, at 50 °C to 570 A, and so on down to 450 A at 70 °C, so the actual ampacity in your enclosure depends on your internal ambient and how tightly you pack the other breakers. Interrupting capacity is 187 kA at 240 V, 121 kA at 415 V and 440 V, 75.6 kA at 500 V, and 17 kA at 690 V. That 187 kA at 240 V is the headline number — it tells you this breaker can clear a bolted fault at the low-voltage transformer secondary without the arc re-striking, which matters for main or tie positions in high-capacity switchboards. It carries an undervoltage release (UVR) as the auxiliary release design, plus two HQ auxiliary switches for status feedback to a PLC or annunciator panel. Communication function is built in — the ETU550 supports Modbus RTU over the optional communication module, letting you pull trip data and waveform captures without a separate gateway.
Integration notes — footprint and panel fit
Dimensions are 248 mm high, 138 mm wide, 110 mm deep. That 110 mm depth is the body only — add clearance for the handle throw, the UVR coil projection, and any communication module plugged into the front face. The 138 mm width is the standard 3-pole MCCB footprint for this frame size; it occupies three 45 mm module positions on a DIN rail or bolts directly to a mounting plate. Maximum power loss is 164.5 W at rated current. That heat has to leave the enclosure — factor it into your thermal calculation, especially if this breaker sits in a sealed stainless steel panel with no forced ventilation.
Selectivity and coordination — what the ETU550 enables
The ETU550 electronic trip unit gives you adjustable I²t curves for long-time and short-time protection, plus a separate instantaneous pickup and ground-fault alarm/trip. That means you can set the short-time delay to ride through downstream feeder breaker faults, achieving full selectivity (discrimination) up to the breaker's short-time withstand rating. For a site electrical engineer building a coordinated distribution system, this is the trip unit that lets you avoid nuisance main-tripping on a branch fault. Rated insulation voltage Ui is 800 V, so the breaker is rated for 690 V systems with margin. Mechanical endurance is 15,000 operations latching — that's the handle mechanism life, not the electrical switching life under load.