Siemens SENTRON 3VA1150-3EF36-0BH0 — 50 A MCCB for Line Protection
The Siemens SENTRON 3VA1150-3EF36-0BH0 is a 3-pole molded case circuit breaker (MCCB) designed for line protection in distribution panels. It carries a continuous current rating of 50 A at 40 °C, with thermal derating to 45 A at 70 °C — the full curve is on the nameplate, so verify ambient against the installed enclosure's internal temperature before committing the BOM line. Breaking capacity is specified per voltage: 75.6 kA at 240 V, 52.5 kA at 415 V, 32 kA at 440 V, and 11.9 kA at both 500 V and 690 V. That covers most industrial service entrances and downstream feeder panels; the 690 V figure matters for 600 V class installations where fault current can exceed 10 kA. Rated insulation voltage is 800 V, so the breaker is suitable for 480/277 V and 600/347 V systems with headroom. Power loss at rated load is 17.1 W maximum — account for that in a sealed, non-ventilated enclosure when stacking multiple breakers.
Built-in Undervoltage Release and Auxiliary Switch Configuration
This unit ships with an undervoltage release (UVR) factory-installed — the designation in the order code flags that. The UVR trips the breaker when supply voltage drops below a threshold, which is standard for motor feeder circuits where automatic restart after a dip is unacceptable. The auxiliary switch block provides 2 auxiliary contacts plus 1 trip alarm switch (HQ). That gives you one N/O and one N/C for status feedback to a PLC or indicator lamp, plus a separate alarm contact that changes state only on a fault trip — useful for differentiating a manual open from an overcurrent event.
Dimensions and Panel Fit
Physical footprint: 130 mm height, 76.2 mm width, 70 mm depth. The 76.2 mm width (3 inches) is the standard 3-pole MCCB envelope for this class — it fits existing SENTRON 3VA panel cutouts and busbar risers without adapter plates.
Operating Environment and Lifecycle
The trip indicator is present, so a visual flag confirms the breaker tripped on fault versus being manually switched off. No communication function, no ground-fault monitoring version — this is a straightforward thermal-magnetic line-protection breaker.