What is the minimum grounding resistance of the distribution box
For most transmission and other larger substations, the ground resistance should be about 1Ω or less. Depending upon the tool cable length and the number of spindles and how they are connected, there are two different alternatives how to meet this requirement. Objective (b) above is achieved by providing a ground system of adequately low resistance and arranged in such a way as to limit to safe levels the touch, step and transferred potentials in the events of ground faults. Whether you're a seasoned pro or just starting out, this comprehensive guide will give you practical insights into proper grounding techniques, with a special focus on how selecting quality materials from a reliable building material supplier impacts your entire system's safety and longevity. For effectively-grounded systems this ratio is usually at least 60 (see IEEE Recommended Practice for Grounding of Industrial and Commercial Power. IN ELECTRICAL STATIONS INCLUDING TRANSMISSION AND DISTRIBUTION SUBSTAT GR THAN 8 FT FROM THE FENCE. THE FENCE SHALL BE GROUNDED SEPARATELY FROM THE GRID UNLESS OTHERWISE NOTED ON THE A PROPRIATE PROJECT DRAWING.
Read More
