This document provides specifications for various distribution boxes including dimensions, mounting sizes, and number of ways. This distribution system is suitable for circuit of AC50/60 Hz,rated voltage up to AC660V,rated current up to 125A of distributing control of modern building such as large office mansion, hotel, commerce department industrial and mining enterprises and so on. It can protect electric appliances from. Technical Services Directorate is made up of the following Departments: Technical Standards and Inspectorate Services Department, Metering Services Department and other Strategic Business Units (Transformer Repair Workshop and Chemical Laboratory). Dimensions included are length, width. 4 KV Substation of the ratings indicated above. The body of the boxes shall have sufficient re- enforcement with suitable size of channels keeping a provision for fixin andle conforming to general. What is a Distribution Box? A distribution box, or DB box, is a circuit breaker enclosure. It is a vital part and central hub of any electrical system. The hub distributes electrical power from a single input source to various circuits throughout a building. It stipulates requirements for enclosure materials, installation dimensions, the mandatory "one equipment, one switch, one RCD" rule, mechanical structure, earthing systems.