1. Main Circuit Connection Method: This is the core distinction. The CL model utilizes wire leads, whereas the CU model employs busbar connections. Wire lead connections offer advantages in installation flexibility, adaptability to spatial constraints, and compatibility with various cable sizes. They are suitable for applications with minimal vibration or where routing freedom is needed. In contrast, busbar connections provide lower connection resistance, higher thermal dissipation efficiency, superior mechanical stability, and enhanced vibration resistance. They are designed for fixed, high-current power distribution systems (e.g., energy storage, industrial power supplies) operating under continuous full load with high-reliability demands. The busbar connection of the CU model represents superior electrical and thermal performance. 2. Implied Application Scenarios & Reliability Tier: Despite identical electrical ratings, the inherent connection difference defines their distinct design philosophies. The CL model is suited for general-purpose or cost-sensitive high-current switching applications. The CU model, due to its busbar interface, ensures lower contact temperature rise and more stable connections under long-term operation at the 1kA rated current. It is therefore targeted at mission-critical systems with stringent requirements for long-term reliability and power continuity. The price differential partly reflects the performance gains from enhanced materials and construction. 3. Installation & System Integration Requirements: Implementing the CU model requires provisions during the system design phase for busbar mounting interfaces, dedicated space, and appropriate fasteners, resulting in a more rigid integration. Directly replacing an existing CL (wire lead) installation with a CU unit necessitates redesigning or modifying the main circuit connection section. This may involve additional adapter busbars, which introduce new connection points and could partially negate the performance benefits of the native busbar design. Conversely, forcing a wire lead connection into a system originally designed for busbars can create a thermal bottleneck and a reliability weak point.