What is the maximum conductor fill percentage allowed in underfloor raceways?

The correct answer is 40 percent because, according to the National Electrical Code (NEC), specific requirements are outlined for conductor fill in raceways. The NEC typically sets a maximum fill percentage for conductors in raceways and similar applications to ensure proper heat dissipation and to minimize the risk of electrical hazards. For underfloor raceways, this limit is established at 40 percent of the raceway's cross-sectional area. Maintaining this fill percentage helps in preventing overheating of the conductors and allows for easier installation and maintenance, ensuring that there is sufficient space for air circulation around the conductors. This standard is critical for the safety and longevity of electrical systems within commercial and industrial settings.