What is the minimum size schedule 80 PVC conduit required for a run containing three 350 kcmil, one 3/0, and one #2 THHN/THWN conductors?

To determine the minimum size of schedule 80 PVC conduit required for the specified conductors, it's important to consider the ampacity and fill calculations per the National Electrical Code (NEC).

For conduit fill, the NEC sets specific filling standards to ensure that conductors can dissipate heat effectively and to reduce the likelihood of damage due to overcrowding. The calculation of the required conduit size starts by looking at the cross-sectional area of the conductors being used.

In this case, the three 350 kcmil, one 3/0, and one #2 THHN/THWN conductors must be converted into their respective areas based on standard wire sizing tables. After calculating the area of each conductor and summing them, this total area is then compared to the fill capacity of various conduit sizes.

The schedule 80 PVC conduit has different fill capacities compared to other types of conduit, and the sizing also depends on whether the conduits are containing more than one type of conductor. According to the NEC, for three or more conductors, the maximum fill is reduced to prevent overheating.

By performing the calculations associated with NEC Table 1 in Chapter 9, it's revealed that for the stated conductor types and quantities, the minimum conduit size