The Siemens 3RV2023-4DA10-ZX95 is a SIRIUS motor protection circuit breaker, size S0, Class 10 trip, 45 mm wide, 97 mm deep. Any mounting position works, which helps in tight enclosures where you can't guarantee vertical.
At 400 V, the magnetic short-circuit release is coordinated with a gG 63 A upstream fuse; at 500 V, that drops to gG 50 A. That's the selectivity window — the breaker's instantaneous trip will clear a fault before the upstream fuse blows, as long as the fuse is sized to those limits. For motor full-load current, the breaker is rated 25 A at both 480 V and 600 V, which covers a 15 hp motor at 460/480 V and a 20 hp motor at 575/600 V. At 230 V it's good for 7.5 hp. The maximum switching rate in AC-3 duty (motor starting) is 15 operations per hour. That's fine for a pump or fan that cycles a few times an hour — not for a jogging or inching application where you're hitting the starter every 30 seconds. For high-cycle loads, step up to a contactor rated for 600+ ops/hr and let the breaker just provide backup protection.
Panel Fit — What Goes Where
That's the standard S0 footprint — same as the base 3RV2023-4DA10. The ZX95 suffix indicates a special version (customer-specific variant or packaging), but the mechanical dimensions and mounting are identical. If you're replacing a 3RV2023-4DA10 in an existing panel, this drops straight in — same screw-terminal layout, same DIN rail clip, same busbar compatibility. Clearance requirements: 50 mm upward and downward, 30 mm to the side, zero forward clearance needed. That's tight enough to stack breakers in a multi-motor panel without wasting rail space. Terminals accept solid or stranded wire: 2×(1 to 2.5 mm²) or 2×(2.5 to 10 mm²), with M4 screws on the main contacts.