When eight current-carrying conductors are in one conduit, the ampacity of each conductor is adjusted to what percentage?

When eight current-carrying conductors are placed in a single conduit, the National Electrical Code (NEC) stipulates that the ampacity of each conductor must be reduced to ensure safety and prevent overheating. According to NEC guidelines, specifically under the adjustment factors for conductors, when there are more than three conductors in a conduit, adjustments to their ampacity are necessary.

For eight conductors, the adjustment factor is specified as 70 percent. This means that each conductor's ampacity should be limited to 70 percent of its rated capacity to account for the heat generated by the conductors operating in close proximity to each other. This reduction is crucial for ensuring that the conductors can operate safely without exceeding the temperature ratings that could lead to insulation failure or fire hazards. Hence, the correct adjustment of 70 percent for each of the eight conductors promotes safer electrical installations in the field.