Question

What size of conduit is required for forty No. 14 RW90, non jacketed, 600 V conductors?

-trade size 27 (1")
-trade size 41 (1 ½")
-trade size 35 (1 ¼")
-trade size 21 (¾")

Answer 1

It offers adequate space to accommodate forty No. Therefore the correct option is Trade size 35 (1 ¼")

Step-by-step explanation:

The total area of forty No. 14 RW90 conductors can be calculated using the formula: Total Area = Number of Conductors × Area of One Conductor. For No. 14 RW90, the area is approximately 2.08 square millimeters. Thus, 40 conductors would require a total area of 83.2 square millimeters.

Conduit fill calculations dictate that the maximum fill percentage should not exceed 40% for power conductors. By referring to the NEC (National Electrical Code) tables, it's observed that a trade size 35 (1 ¼") conduit provides ample space for the 83.2 square millimeters needed for these conductors while staying within the 40% fill limit.

Therefore the correct option is Trade size 35 (1 ¼")