What it is and where it goes
This is a Siemens SENTRON 5SY7313-8 miniature circuit breaker — 3-pole, D-curve, rated 13 A at 400 V AC. It's the part you reach for when you need high inrush immunity on motor or transformer circuits, not general lighting. Rated breaking capacity sits at 15 kA per EN 60898 and 25 kA per IEC 60947-2, with a DC rating of 15 kA per IEC 60947-2. That's enough headroom for most industrial panel sub-feeders without stepping up to a larger frame. It snaps onto a DIN rail via the quick assembly system, takes 3 modular width units (54 mm), and mounts in any position. The 76 mm depth leaves room in a shallow enclosure. Rated for overvoltage category III and pollution degree 3, it's built for fixed installation in industrial control panels, mechanical engineering, and distribution boards.
What the D-curve means on a real line
The D tripping characteristic means magnetic trip occurs at 10 to 20 times rated current (In). For a 13 A breaker, that's 130 to 260 A instantaneous — so it won't nuisance-trip on motor starting or transformer inrush, but it still clears a hard short fast. If your load is mostly resistive or general-purpose with moderate inrush, a C-curve sibling (like 5SY7140-8CC) trips at 5–10× In and gives faster fault clearance. The D-curve here is the right call for drives, pumps, and compressors.
Lifecycle and sourcing reality
For UL 1077 / CSA C22.2 No. 235 applications, the breaking capacity is 5 kA — check your panel SCCR if you're specifying for a North American job. The IEC ratings (15/25 kA) are what govern in European and most global installations.
Integration notes
Combined terminals top and bottom accept both busbar and cable — no need to swap lugs between feed and load. Sealable to prevent tamper; halogen-free and silicon-free construction matters if the panel is in a clean room or food processing area. Ambient operating range is -40 °C to 75 °C, but humidity derates above 55 °C: 95% RH up to 55 °C, then 55% RH up to 70 °C, then 35% RH up to 75 °C. If your panel sits in a hot, humid environment (near a washdown station or outdoor cabinet in the tropics), factor that into the thermal design. Vibration resistance per IEC 60068-2-6: ±1 mm at 5–25 Hz, 50 m/s² at 25–150 Hz. It holds up on a machine frame or conveyor line without loosening.