Red Seal Electrician Practice
Motor controlsQuestion 234 of 1506

In a ladder diagram of a 120 V AC control circuit, what are L1 and L2?

  1. L1 is the grounded neutral; L2 is hot
  2. L1 is hot; L2 is the grounded neutral
  3. Both are hot wires from a 240 V supply
  4. L1 is the equipment ground; L2 is neutral
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Correct answer: L1 is hot; L2 is the grounded neutral

L1 and L2 name the two rails of the control supply. L1 is the hot wire and L2 is the grounded wire.

Source: Lessons in Electric Circuits IV: Digital (Kuphaldt), 6.1: “Ladder” Diagrams

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Questions last reviewed: 18 October 2026