What it is and what the ratings mean
The Siemens SENTRON 5SY3002-7 is a 1P+N miniature circuit breaker rated 2 A with a C tripping characteristic and a 4.5 kA breaking capacity per EN 60898. The C-curve means it trips between 5 and 10 times rated current — suited for moderate inrush loads like small motors, lighting banks, and transformer primaries where you need short-circuit protection without nuisance tripping on startup. The 4.5 kA interrupting rating at 230 V AC tells you it can safely clear a fault up to that level on the secondary side of a residential or light commercial distribution board; anything above that and you need an upstream limiting device. Rated current derates with ambient temperature: 2 A at 30 °C, 1.92 A at 40 °C, 1.88 A at 45 °C. If the breaker sits in a warm enclosure or next to other heat-generating devices, factor the derating into the load calculation — the 40 °C figure is the one to use for a typical closed panel.
Panel fit and deployment
Snaps onto standard DIN rail (EN 60715), occupies one modular width (18 mm). Depth is 76 mm, installation depth 70 mm — fits standard distribution boards and sub-panels without bottoming out on the gland plate. Mounting position is any, so it works in vertical or horizontal busbar arrangements. IP20 with connected conductors; fine for enclosed distribution boards, not for wet or dusty environments without an outer enclosure. Touch protection is built in (finger-safe terminals per the spec), and the breaker is sealable — useful for utility metering or rental applications where tamper evidence matters. Halogen-free and silicon-free construction matters if the panel serves sensitive environments like clean rooms or medical areas where outgassing during a fault could contaminate the space.