The most significant factor that determines the minimum approach distance is the voltage of the overhead line. The higher the voltage, the larger the required safety distance. This is because higher voltages can arc over greater distances. For example, the MAD for a 33 kV line is considerably less than for a 110 kV line.

Other factors include:

• Environmental Conditions: High humidity, rain, or pollution can reduce the insulating properties of the air, potentially increasing the required safe distance.

• Work Method: Whether the work is being done live (with the line energized) or de-energized, and whether the worker is using insulated tools or standing on the ground, will also affect the specific MAD.

• Local Regulations: Safety regulations vary by country and region. It's essential to always consult and adhere to the specific standards set by local authorities, such as OSHA in the United States or similar bodies elsewhere.