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. 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.
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 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
No neutral conductor switching (this is a line-only breaker).