The bottom edge of the distribution box is usually between 1. 8 meters above the ground, which is convenient for operation and inspection. According to the "Code for Acceptance of Construction Quality of Building Electrical Engineering" GB50303-2002, the vertical distance between the bottom surface of the fixed stainless steel enclosure ip67 and the ground should be greater than 1. Generally, distribution boxes can be divided into three levels of secondary protection, that is, three levels of distribution boxes: general. 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. Electrical clearances are the minimum separation distances the National Electrical Code (NEC) requires between wiring, panels, overhead conductors. Pick your state and browse state-approved Electrician CE courses — complete your continuing education hours online, with instant reporting. When a substation fence is expanded or a section is removed, fence sections shall be isolated, grounded, or bonded as necessary to protect employees from hazardous differences in electric potential. Note to paragraph (d): IEEE Std 80-2000.