How many hours in advance must the One Call System be contacted before starting digging operations?

The correct requirement is to contact the One Call System 48 hours in advance before starting any digging operations. This timeframe is essential to ensure that utility companies can locate and mark any underground utilities in the area where the digging will occur. By allowing 48 hours, there is adequate time for the notification to reach all necessary parties, decreasing the risk of disrupting services or causing safety hazards such as hitting buried lines. This practice is critical for maintaining safety standards and protecting both workers and the infrastructure of the community. The other timeframes do not provide sufficient notice for the comprehensive response required from utility operators, which can lead to potential delays in the work or increased risk of accidents.