What is the maximum conductor size allowed in a cellular concrete floor raceway without special permission?

The maximum conductor size allowed in a cellular concrete floor raceway without special permission is 1/0 AWG. This specification is often driven by safety considerations and the need to ensure that the raceway can effectively manage heat dissipation and accommodate the physical properties of conductors within the confined space of a concrete floor.

Using larger conductors can lead to challenges such as increased heat generation, which may not be mitigated adequately in a cellular concrete environment. Therefore, the electrical codes and standards set this limitation to ensure safe installations and to protect the integrity of the raceway system. This size also aligns with common practices and code requirements, providing a balance between capacity and safety without the need for additional approvals or modifications.