Which conductor size is the maximum allowed in cellular metal floor raceways without special permission?

In the context of cellular metal floor raceways, the maximum conductor size permitted without requiring special permission is 2 AWG. This specification is based on the National Electrical Code (NEC) guidelines which specify limitations on conductor sizes to ensure safety and compatibility with raceway dimensions and installation practices.

Using 2 AWG as the maximum allowed size ensures that the conductors can fit within the confines of the raceway without causing overcrowding or potential overheating issues. Larger conductors could lead to difficulties in installation and could create hazardous conditions if they do not provide adequate space for heat dissipation.

Also, it keeps in mind the physical limitations of the raceway system in terms of fill percentages, considering the number of conductors and their respective sizes to avoid exceeding recommended fill limits which could lead to overheating and insulation damage. Smaller conductors, such as 4 AWG or 8 AWG, would also fit, but the key point here is that 2 AWG is the largest size that can be installed without further permissions, promoting a balance between functionality and safety.