What is the ampacity adjustment factor for three conductors in a conduit?

The ampacity adjustment factor for three conductors in a conduit is 70%. This adjustment factor is derived from guidelines established in electrical code regulations, specifically those aiming to ensure safe wiring practices. When multiple conductors are grouped together, they tend to produce additional heat due to the increase in current flow and the restricted space for heat dissipation.

The adjustment factor compensates for this heat buildup, helping to prevent overheating of conductors, which can pose fire hazards or damage the insulation over time. In the case of having three conductors in a conduit, the 70% factor allows the system to operate safely by effectively limiting the maximum allowable current, ensuring that the conductors can handle the load without risk of failure.

Using this adjustment factor is essential for maintaining the safety and efficiency of electrical installation, especially in environments where temperature rise is a concern. Hence, for three conductors in a conduit, using the 70% ampacity adjustment factor is both a prudent and code-compliant practice.