Picking the right box means you must check power needs, voltage, and safety ratings. You should always get a licensed electrician to install it. They give safe and. (3) Power distribution from tertiary switch boxes to electrical equipment must follow the “one machine, one switch” principle, with no branching allowed. "Two level protection" mainly refers to the use of leakage protection measures. In addition to installing leakage protectors in the final switch box, a first level leakage protector should also be installed. A three phase distribution box controls and guards electricity in three-phase power systems. Many factories and businesses use these boxes to run things like motors, air compressors, and heaters. Big buildings with many floors. The distribution box is an electrical equipment with the characteristics of small size, easy installation, special technical performance, fixed position, unique configuration function, no site restrictions, widespread application, stable and reliable operation, high space utilization rate, small. Connects to end-use equipment via switch boxes, forming a three-tier power distribution system. Residual current devices (RCDs) at both the tertiary (equipment-level) and secondary (zone-level) stages. The following is a detailed introduction about it: - **First-level Distribution.