Journeyman Electrician Practice Exam

What is the maximum number of size 1 AWG XHHW compact conductors allowed in a 3-inch Schedule 40 rigid PVC conduit?

1. 15

2. 18

3. 21

4. 24

The correct answer is: 21

The correct answer is based on the National Electrical Code (NEC) guidelines for conduit fill, which specify the maximum number of conductors that can safely fit within a given conduit size. For nonmetallic conduits such as Schedule 40 PVC, the allowable fill for size 1 AWG XHHW compact conductors must be calculated based on the conduit’s internal diameter and the cross-sectional area of the conductors. Specifically, for a 3-inch Schedule 40 PVC conduit, the NEC references indicate a specific maximum fill percentage that ensures safety and performance, preventing overheating and allowing for heat dissipation. The mium of 40% for conductors that are not considered to be larger than a certain percentage of the conduit diameter is typically applied. When applying the NEC’s calculations for conduit fill, it has been established that you can fit up to 24 conductors of size 1 AWG XHHW into the 3-inch Schedule 40 PVC conduit without risking overcrowding, which can lead to heat buildup and potentially hazardous conditions. Thus, given these considerations, the maximum number of size 1 AWG XHHW compact conductors allowed in a 3-inch Schedule 40 rigid PVC conduit is correctly identified as