Panel fit and derating
The Siemens 5SU1324-6FM20 is a 2-pole RCBO from the SENTRON 5SU1 series, combining overcurrent and residual current protection in a single 54 mm wide unit (3 width units).
Thermal derating curve
At 40 °C it's 18.8 A, at 45 °C it's 18.2 A, at 50 °C it's 17.4 A, at 55 °C it's 16.2 A, at 60 °C it's 16.2 A, at 65 °C it's 15.4 A, and at 70 °C it's 14.6 A. If the panel runs hot — say 50 °C inside a sealed enclosure — the usable continuous current drops to 17.4 A.
Overvoltage category III. Energy limiting class 3. Halogen-free and silicon-free construction. IP20 with distribution board installed and conductors connected. The product is classified per DIN EN 61346-2 and DIN EN 81346-2 as function F.