What it is and where it fits
The Siemens 3RV2142-4JA10 is a SIRIUS motor protection circuit breaker with an integrated overload relay function, designed to protect motors against short circuits, overloads, and phase failure. It snaps onto 35 mm DIN rail per DIN EN 60715 and uses screw-type terminals for the main circuit, so it lands in a standard motor control center or panel without surprises. Rated breaking capacity hits 50 kA at 400 V, which is enough to handle a stiff utility fault without cascading upstream. The Trip Class 10 means it trips fast enough to protect standard induction motors during a locked-rotor event — out here in the grease, that's the difference between a quick restart and a rewind job.
Key ratings and what they mean for your panel
At 400 V, the 50 kA interrupting rating covers most industrial secondary-side faults. At 690 V, it still holds 4 kA — enough for a 690 V motor branch in a European-style panel. The unit also carries a 63 A continuous rating at 480 V and 600 V, so it sizes into the 40–60 A motor range comfortably. Phase failure detection is built in — the unit will drop the motor on a lost phase before single-phasing cooks the winding. No ground fault detection on this variant, so if you need that, you'd add a separate ground-fault module downstream. Mounting position is any, which helps when you're squeezing this into a tight corner of the enclosure. Clearance requirements: 150 mm above and below, 30 mm to the side, and zero forward or backward — so it can sit flush against the backplane.
Lifecycle and sourcing reality
Sourcing is straightforward — we quote this part to order against an RFQ through our independent distribution channels. Availability and current pricing are confirmed at quote time. No long lead-time surprises on an active-line item like this.