According to NEC tables, how many conductors are allowed in a raceway without derating?

The maximum number of conductors allowed in a raceway without derating, according to the National Electrical Code (NEC) tables, is three conductors. This rule is established to ensure that the conductors can safely carry their rated amperage without overheating.

When more than three conductors are placed together in a confined space like a raceway, the heat generated from the conductors can accumulate, leading to elevated temperatures that could exceed the insulation ratings. For this reason, the NEC specifies a threshold (in this case, three conductors), above which derating factors need to be applied to ensure safety and reliability.

By allowing up to three conductors without derating, the NEC helps maintain the integrity of the electrical installation and protect against potential hazards such as electrical fires caused by overheating.