Siemens 3VA2125-5HL42-0AA0 — SENTRON MCCB, 25 A, 4-Pole
The Siemens 3VA2125-5HL42-0AA0 is a 4-pole molded case circuit breaker from the SENTRON line, rated for 25 A continuous current and designed for line protection. It carries an interrupting capacity of 187 kA at 240 V and 121 kA at 415 V, so it clears high-fault currents on a 400 V distribution panel without cascading upstream — the SCCR headroom is what allows a single MCCB to protect a transformer-fed bus.
The ETU320 overcurrent release is a thermal-magnetic trip unit; it handles overloads (thermal curve) and short-circuits (magnetic instantaneous) without external power. The 25 A continuous rating holds flat from 40 °C through 70 °C — no derating needed in a warm enclosure, which is uncommon for a compact MCCB. Insulation voltage is rated 800 V, so the breaker can sit on a 690 V line (where interrupting capacity drops to 3.7 kA — still adequate for most motor branch circuits at that voltage).
Dimensions are 140 mm wide, 181 mm high, 86 mm deep — a standard SENTRON 3VA2 frame footprint.