Section 4. Notification to Power Company and Responsibility for Safeguards.--Whenever activity is to be performed requiring precautionary action under section 2, the employer, contractor or other person responsible for the activity shall, promptly notify the owner or person in charge of the high-voltage line of the intended activity and shall fully comply with and shall be responsible for the cost and for the completion of the precautionary action required under section 2 before proceeding with such activity.