Compare the total copper cross sections in terms of current-carrying capacity for a single-phase system and a three-phase 120 V system with an effective load of 50 Ω.
A) Single-phase 7.2 A; three-phase 4.8 A
B) Single-phase 4.8 A; three-phase 2.4 A
C) Single-phase 9.6 A; three-phase 14.4 A
D) Single-phase 4.8 A; three-phase 0 A

Question

Quizplus · Accepted Answer

For a single-phase system, the current is I = V/R = 120V/50Ω = 2.4 A. For a three-phase system, the line current is I = V_phase/R = (120V/√3)/50Ω = 1.39 A. Total current capacity is higher in single-phase.

Compare the Total Copper Cross Sections in Terms of Current-Carrying