When selecting leakage protectors, you must prioritize Rated Current (In), typically ranging from 16A to 100A, and Rated Residual Operating Current (IΔn), where 30mA is the standard for life safety and 100mA-500mA is used for fire protection. Ensure the device has a high breaking capacity (Icn), usually 6kA or 10kA, to handle short-circuit scenarios effectively. Additionally, verify the tripping characteristic (Type AC, A, or B); Type A is increasingly preferred as it detects both AC and pulsating DC residual currents, which are common in modern electronics.