What it is and what the ratings mean
The SENTRON 5SY8324-8BB08 is a 3-pole miniature circuit breaker with a D tripping characteristic, rated 12.5 A at AC. That D-curve means it's built for loads with high inrush — think motor starters, welding equipment, or transformer primaries — where the magnetic trip holds off through the start surge and clears only on a sustained overload or short. Breaking capacity is 30 kA per IEC 60947-2, which puts it in the range for most industrial panel main-feeders and sub-distribution where fault currents can hit that level. For UL 1077 / CSA C22.2 No. 235 installations, the rating is 5 kA — a different standard, so check which code governs your site. Magnetic-only tripping operation means no thermal bimetal; this breaker responds to short-circuit current only. It's the right choice when upstream or downstream devices handle overload protection and you need a dedicated magnetic element for fault isolation in a coordinated system.
Panel fit and environment
Snaps onto DIN rail via the quick-assembly system, occupying 3 modular width units (54 mm). Depth is 76 mm, installation depth 70 mm — fits standard 80 mm deep enclosures with room for wiring behind. Mounting position any, so vertical or horizontal busbar orientation works. IP20 with connected conductors — fine inside a closed panel, not for wet or washdown zones. Ambient range -40 °C to 75 °C, with humidity derating: max 95% RH at 55 °C, dropping to 35% at 75 °C. Vibration rated per IEC 60068-2-6: ±1 mm at 5–25 Hz, 50 m/s² at 25–150 Hz. Halogen-free and silicon-free construction matters if this breaker lives in a clean room, semiconductor fab, or any environment where outgassing contaminates processes. Sealable design lets you lock the toggle with a padlock for lockout/tagout.
Electrical ratings and approvals
Rated voltage 440 V AC for both single-phase and multi-phase operation. Maximum DC operating voltage is 72 V — usable in DC control circuits but keep the voltage below that. Frequency 50/60 Hz standard. Overvoltage category III, pollution degree 3. Mechanical service life 10,000 switching cycles typical. Combined terminals top and bottom accept copper conductors; touch protection is built into the terminal design. Neutral conductor switching is not a function of this unit — it's a straight 3-pole breaker. Classification per DIN EN 61346-2 is F (protective device). Suitability for operation listed as mechanical engineering and industry — that's the target application for this D-curve magnetic-only breaker.
Lifecycle and sourcing
Current production — no end-of-life notice on this order code. Sourced and quoted to order against an RFQ through independent distribution; availability and current pricing confirmed at quote time.