What percentage of the conduit cross-section is utilized when more than two conductors are present?

When more than two conductors are present within a conduit, the National Electrical Code (NEC) provides guidelines for calculating the permissible fill percentage. For conduits containing multiple wires, the code establishes that no more than 40% of the conduit cross-sectional area should be filled when there are more than two conductors present. This fill percentage is vital in ensuring that conductors have enough space for heat dissipation and to minimize any potential damage to the insulation and conductors themselves.

Understanding this fill requirement is critical for maintaining the performance and safety of fire alarm systems, where proper installation can significantly affect their reliability and functionality. Therefore, the choice indicating 40% utilization effectively aligns with NEC guidelines, confirming that it is the correct answer in this context.