Distribution box and switch box should not exceed 30 meters. Working space: The front clearance, side clearance, and height clearance requirements for electrical equipment that provide a safe area for maintenance, inspections, and other work. Switchboards must be located and installed with adequate space, ventilation, and accessibility to prevent overheating, facilitate easy maintenance, and ensure safe emergency. Need to renew your Electrician license? Pick your state and browse state-approved Electrician CE courses — complete your continuing education hours online, with instant reporting. Generally, distribution boxes can be divided into three levels of secondary protection, that is, three levels of distribution boxes: general. Since April 1997 the sising of clearance and creepage distances has been covered by DIN VDE 0110 part 1 “Insulation coordination for electrical equipment in low-voltage systems”. DIN VDE 0110 part 1 contains the modified edition of IEC Report 664-1 (see also IEC 664-1/Oct 1992). The design data. Present in any type of electrical installation, the junction boxes are important for promoting the passage of the wires inside walls, as well as to connect wires to sockets and switches.