What is the preferred condition for crane operation near power lines?

The preferred condition for crane operation near power lines involves ensuring safety by de-energizing and grounding these lines. When power lines are de-energized and grounded, it effectively eliminates the risk of electrical hazards during crane operation, thus providing a secure environment for the workers and the equipment involved. This precaution is crucial because cranes can inadvertently make contact with power lines, leading to serious accidents, including electrocution.

While other options suggest measures to mitigate risk, such as elevating power lines, insulating them, or hoping they do not influence operations, these do not provide the comprehensive safety assurance that de-energizing and grounding does. De-energizing the lines ensures they are not live, while grounding disperses any potential electrical charge safely into the earth. Hence, the emphasis on this option makes it the safest and most preferred approach when working near power lines.