Motor protection circuit breaker, 6.3 A, CLASS 10 — what the ratings mean
The Siemens 3RV1021-1GA10-ZW95 is a SIRIUS motor protection circuit breaker rated for 6.3 A continuous current and a CLASS 10 trip characteristic, meaning it disconnects a locked-rotor motor within 10 seconds at its cold start — fast enough to protect standard induction motors from thermal damage during a stall or jam. It delivers 100 kA breaking capacity at 400 V AC, so it safely interrupts high-fault currents up to that level without upstream fuses; at 690 V the rating drops to 6 kA, which still covers most industrial supply points. Phase-failure detection is built in, so it trips on a lost phase before single-phasing cooks the winding. It is designed for motor protection, not general branch-circuit protection — the CLASS 10 curve matches motor start-up inrush, not resistive loads.
Panel integration and wiring
Mounts via screw and snap-on onto 35 mm standard mounting rail per DIN EN 50022 — no adapter plate needed. Width is 45 mm, height 97 mm, depth 96 mm; backwards clearance is 0 mm, side clearance 0 mm, so it packs tight against adjacent devices in the row. Screw-type terminals on both main and auxiliary circuits accept solid or stranded conductors: 2x (1... 2.5 mm²) and 2x (2.5... 6 mm²) per clamp, with fine-stranded wire requiring a ferrule. AWG equivalents are 2x (14... 10). The front face carries IP20 protection — safe for finger contact inside a closed panel, but not for washdown environments.
Operating conditions and approvals
Runs at -20 °C to +60 °C ambient during operation; storage and transport tolerate -50 °C to +80 °C. Shock resistance is 25g for 11 ms. Surge voltage withstand is 6 000 V. The part carries a substance prohibition date of 01.05.2012, aligning with RoHS and REACH compliance milestones. It is rated for AC-3 duty up to 690 V with a maximum of 15 operations per hour. Power dissipation at rated load is 7.25 W total, 2.4 W per pole — small enough that no special ventilation is needed in a standard enclosure.