Include protection devices like breakers, fuses, and surge protectors—each circuit should have its own protection. Comply with standards: Follow NEC, IEC, or local codes. Select qualified products that meet national standards and safety requirements. According to the electrical design requirements, determine the appropriate installation location and. A distribution box is the heart of any electrical system. However, the key to. DTU (Distribution Terminal Unit), a substation terminal in distribution automation systems, is secondary equipment installed in switching stations, distribution rooms, N2 Insulation ring main units (RMUs), and box-type substations. Whether it is residential buildings, commercial facilities or industrial sites, the.