The Siemens 5SL4204-6 is a 2-pole SENTRON miniature circuit breaker rated 4 A with a B tripping characteristic and 10 kA breaking capacity per both EN 60898 and IEC 60947-2. That 10 kA figure is the fault current it can safely interrupt — match it to the prospective short-circuit current at the panelboard. The B-curve trips between 3 and 5 times rated current, so it's sized for resistive and general lighting loads where inrush is low; not for motor circuits that need a C or D curve.
Panel fit and mounting
Two modular width units (36 mm) on a DIN rail, 76 mm deep behind the panel face. Mounting position is unrestricted — horizontal, vertical, upside-down, the thermal-magnetic trip works the same. The IP20 rating (with connected conductors) means it's for enclosed panel use only, not for wet or dust-exposed locations. Sealable terminals are standard, so a lockable cover can be fitted to prevent tampering on metered or critical circuits.
Environmental range
Rated for ambient temperatures from -40 °C to +75 °C, which covers unheated electrical rooms and outdoor enclosures in most climates. Halogen-free and silicon-free construction — relevant for installations in clean rooms, semiconductor fabs, or areas where outgassing must be minimized. Pollution degree 2 (non-conductive pollution only) and overvoltage category III, so it's suited for fixed-installation distribution boards downstream of the main service entrance.