What this MCCB delivers — and what the ratings actually mean
The Siemens SENTRON 3VA2125-5JQ42-0AA0 is a 4-pole molded case circuit breaker (MCCB) rated for 25 A continuous current, with an ETU560 electronic trip unit. That 25 A holds flat from 40 °C all the way to 70 °C — no derating curve to chase in a hot panel, which is rare for a breaker this compact. The breaking capacity hits 187 kA at 240 V and 121 kA at 415 V, so it handles high-fault scenarios like transformer secondaries or large motor control centers without cascading upstream. At 690 V it still clears 3.8 kA, enough for most 690 V distribution. The ETU560 release gives you adjustable long-time delay (tr) from 0.5 to 25 seconds, plus adjustable N-conductor protection (OFF, 40% to 160%) — useful for sizing the neutral on 4-wire systems where harmonics or unbalanced loads are a concern. Communication function is built in, so it can talk to a BMS or SCADA without an add-on module.
Panel fit and integration
The 3VA2125-5JQ42-0AA0 measures 140 mm wide, 181 mm tall, and 86 mm deep — a 4-pole MCCB that fits standard SENTRON mounting plates and busbar systems. Front protection is IP40, so it's fine for enclosed distribution boards but not for washdown areas. Latching endurance is rated at 20,000 operations, which is typical for a distribution breaker that sees infrequent switching. Rated insulation voltage is 800 V, giving headroom for 690 V systems.