Part overview and key ratings
The 5SJ4304-8HG42 is a 3-pole D-curve miniature circuit breaker for 50 Hz systems. Interrupting capacity is 10 kA and 15 kA. Rated operational voltage is 400 V AC, 60 V DC. The insulation voltage is 440 V AC. It mounts on a standard DIN rail in any orientation, occupies three modular width units (54 mm), and the overall dimensions are 54 mm wide by 121 mm tall by 70 mm deep. IP20 with conductors connected; IP40 in the handle area. The 5SJ4304-8HG42 is halogen-free and silicon-free, which is worth noting if your panel sees sensitive environments (food, chemical) where off-gassing or contamination is a concern. It can be sealed and is rated for vibration up to 50 m/s² across 25–150 Hz.
How it compares to the 5SY series
Our ledger includes three peer MPNs from the 5SY line — 5SY4350-8, 5SY4363-8, 5SY4380-7. These are also 3-pole miniature circuit breakers, but they belong to Siemens’ Standard product family, not the SENTRON brand. The 5SJ4 series is explicitly designated for mechanical engineering and industry; the 5SY line is more general-purpose. Without confirmed specs for the 5SY parts (interrupting rating, trip curve, certification), we cannot say they are drop-in replacements. If your BOM was built around 5SY4350-8, verify the required interrupting capacity and characteristic before substituting the 5SJ4304-8HG42. The two series have different ordering trees and documentation scopes.
Lifecycle and sourcing
Lifecycle status is current (active). No last-time-buy or phase-out notification is attached to this order code. It can be quoted to your required quantity and schedule through our normal supply chain — no broker hunt needed. Just tell us the quantity and target delivery window.
Mounting and environmental notes
Mounts on a standard 35 mm DIN rail; any orientation is allowed, which simplifies panel layout. The combined terminals at top and bottom accept Cu conductors; tighten to 3.5 Nm. No neutral conductor switching (this is a line-only breaker). Ambient temperature range is -40 °C to +75 °C, with up to 95% humidity. Suitable for pollution degree 3 and overvoltage category III.