What size schedule 40 rigid PVC is required for a 10/2 NM cable containing two cables?

To determine the appropriate size of schedule 40 rigid PVC conduit for a 10/2 NM cable containing two conductors, we need to reference the National Electrical Code (NEC) guidelines that govern the fill capacity of conduits. The NEC provides tables that outline the maximum number of conductors allowed in a conduit based on the size of the conduit and the type of conductors.

For two conductors of 10 AWG in a non-metallic sheathed (NM) cable, when calculating conduit fill, the key factors include the overall diameter of the cable and the allowed fill percentage for the specific conduit size.

A 10/2 NM cable typically has a diameter of about 0.32 inches. When using the NEC conduit fill calculations, it indicates that for one or two NM cables, a conduit diameter closer to 1 1/4 inches is often suitable to remain within the fill limits, while still allowing for ease of pulling the cables through.

Choosing 1 inch would likely violate the fill limits or make it difficult to pull the cables through, while 1 1/2 inch and 2 inch sizes would exceed the requirements, leading to unnecessarily larger conduit. Therefore, the best size that meets both the NEC guidelines