The Siemens 5SY7550-6 is a SENTRON miniature circuit breaker (MCB) with a B tripping curve, rated 50 A at 230 V AC, in a 2-pole (1P+N) form factor. It provides overcurrent and short-circuit protection for branch circuits in industrial control panels and building distribution boards, with a breaking capacity of 15 kA per EN 60898 and 20 kA per IEC 60947-2.
Rated 50 A with a B characteristic means it trips magnetically at 3 to 5 times rated current — suited for resistive and general-purpose loads where inrush is moderate, like lighting circuits or small motor feeders with separate overload protection. Breaking capacity of 15 kA at 230 V AC per EN 60898 covers most commercial and light-industrial fault levels; the higher 20 kA rating per IEC 60947-2 applies when the MCB is used in an industrial context where the prospective short-circuit current may be higher. Mounting position is any orientation, simplifying layout. Terminals accept solid or stranded conductors from 0.75 to 35 mm² — enough for the full 50 A circuit without pigtails. Combined terminal design (top and bottom) supports both busbar and cable entry.
Where it goes and environmental limits
Rated for ambient temperatures from -40 °C to +75 °C, with humidity limits up to 95 % at 55 °C — suitable for unheated enclosures in temperate or cold climates, and for warm cabinet interiors near other heat sources.