What prepares tables showing the safe current ratings for sizes and types of conductors with various types of insulation?

The correct answer is found in the organization that specifically develops standards related to electrical safety and practices, including tables detailing safe current ratings for conductors based on their size, type, and insulation characteristics. The National Board of Fire Underwriters plays a key role in establishing safety codes and regulations concerning the electrical systems to prevent fire hazards and ensure proper safety practices in installations.

This organization collaborates with others to create comprehensive guidelines that electrical professionals reference when determining safe current carrying capacities, which are crucial for avoiding overheating and potential electrical fires. Their standards help ensure that conductors are adequately protected against current overloads, taking into account factors like ambient temperature, type of insulation, and installation conditions.

Among the other organizations listed, while the National Electrical Code does establish important safety standards, it does not specifically prepare the tables mentioned in the question. The Institute of Electrical and Electronics Engineers primarily focuses on advancing technology and innovation, and Underwriters Laboratories is a well-known testing and certification organization that ensures products meet safety standards rather than directly creating tables with rated currents for conductors.