Red Seal Electrician Practice
Safety and work practicesQuestion 605 of 1506

A disconnect switch feeding a load is open. Where does the full source voltage appear in the circuit?

  1. Across the load connected to the switch
  2. Across the open contacts of the switch
  3. Across the grounded conductor of the circuit
  4. Nowhere, because no current flows in the circuit
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Correct answer: Across the open contacts of the switch

With the circuit broken, the load has zero voltage and the open switch drops the whole source voltage.

Source: Lessons in Electric Circuits I: DC (Kuphaldt), 3.5: Safe Practices

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Questions last reviewed: 18 October 2026