Red Seal Electrician Practice
Wiring and componentsQuestion 423 of 1506

In a 120 V/240 V single-phase three-wire system, what is the voltage between the two line conductors?

  1. 120 V
  2. 208 V
  3. 240 V
  4. 360 V
Show answer

Correct answer: 240 V

The two 120 V sources are in series aiding, so line to line is 240 V.

Source: Electrical Fundamentals Competency (Industry Training Authority of BC), 7.4: Three-wire Power Supply System

Practice wiring and components

Questions last reviewed: 18 October 2026