What size Schedule 40 PVC is required for eight 6 AWG XHHW conductors?

What size Schedule 40 PVC is required for eight 6 AWG XHHW conductors?

• A. 3/4"
• B. 1"
• C. 1 1/4"
• D. 1 1/2"

Answer: (C)

Conduit fill is what’s being tested here. In a raceway, the total cross‑sectional area occupied by insulated conductors cannot exceed about 40% of the conduit’s internal cross‑section. So you determine the combined space eight insulated 6 AWG XHHW conductors would take, and then see which conduit sizes can accommodate that amount of fill at the 40% limit. Eight 6 AWG XHHW conductors are large enough that the combined insulated cross‑section requires more than what smaller sizes can provide. The smaller sizes (the 1/2" and 3/4" conduits) don’t offer enough room within the 40% fill limit, and the 1" conduit is also insufficient. The 1 1/4" Schedule 40 PVC conduit has enough internal area to hold eight insulated #6 conductors within the allowed fill, making it the smallest conduit size that meets the requirement. If a grounding conductor were included, it would count as half for fill, potentially increasing the size further, but with eight conductors the stated result still holds.

Conduit fill is what’s being tested here. In a raceway, the total cross‑sectional area occupied by insulated conductors cannot exceed about 40% of the conduit’s internal cross‑section. So you determine the combined space eight insulated 6 AWG XHHW conductors would take, and then see which conduit sizes can accommodate that amount of fill at the 40% limit.

Eight 6 AWG XHHW conductors are large enough that the combined insulated cross‑section requires more than what smaller sizes can provide. The smaller sizes (the 1/2" and 3/4" conduits) don’t offer enough room within the 40% fill limit, and the 1" conduit is also insufficient. The 1 1/4" Schedule 40 PVC conduit has enough internal area to hold eight insulated #6 conductors within the allowed fill, making it the smallest conduit size that meets the requirement. If a grounding conductor were included, it would count as half for fill, potentially increasing the size further, but with eight conductors the stated result still holds.