What the ratings mean for fit
The Siemens 5SL4520-7 is a 1P+N miniature circuit breaker from the SENTRON family, rated 20 A with a C tripping characteristic. The C-curve means it trips at 5 to 10 times rated current — suited for circuits with moderate inrush, like residential lighting and general-purpose socket outlets, where the magnetic trip avoids nuisance tripping on transformer or motor starting currents. Breaking capacity is 10 kA per both EN 60898 and IEC 60947-2. That 10 kA rating is the maximum prospective fault current the breaker can safely interrupt at 230 V AC — critical for verifying selectivity with upstream devices and ensuring the installation's SCCR is met. Overvoltage category III and pollution degree 2 confirm it's rated for fixed-installation distribution boards, not just final circuits.
Panel integration and sourcing
The 5SL4520-7 occupies 2 modular width units (36 mm) on a DIN rail, with a depth of 76 mm and installation depth of 70 mm. Mounting position is any, which simplifies layout in crowded enclosures. The IP20 rating applies with connected conductors — standard for distribution board use, not for wet or washdown environments. Sealable design allows the installer to lock the toggle position for tamper resistance.