What determines the minimum distances that any part of the plant and machinery must be kept from overhead electricity lines?

The minimum distances that any part of the plant and machinery must be kept from overhead electricity lines are determined primarily by the voltage of the electricity and the materials used for the poles. High voltage lines require larger safety clearances due to the increased risk of electrical arcing, which can occur if machinery gets too close to a live line. The material of the poles can also play a role in these determinations, as different materials may offer varying levels of insulation and structural integrity, affecting how the lines might interact with machinery if an incident occurs.

Understanding these factors is critical for ensuring safety when operating heavy machinery near overhead power lines, as improper distances can lead to accidents that put workers at risk of electrocution or other injuries. Therefore, both the voltage and the type of poles are essential in setting safe operational parameters around high voltage lines, making this the correct answer. Other factors, like the type of machinery being used, the time of day, or weather conditions, may influence how work is conducted, but they do not dictate minimum distance requirements.