The Siemens 5SL6406-6BB is a 4-pole miniature circuit breaker rated 400 V with a 6 kA breaking capacity, B-curve trip characteristic, and 6 A rated current, in the Italy version of the 5SL6 series. The B-curve trips between 3 and 5 times rated current, so this 6 A breaker clears overloads from 18 A to 30 A — typical for resistive and general-purpose loads where moderate inrush is expected, not motor starting or transformer primaries.
Panel integration
The 4-pole body occupies four modular 18 mm width units, so plan for 72 mm of rail space plus finger-duct clearance on the line and load sides.