Red Seal Electrician Practice
Wiring and componentsQuestion 64 of 1506

What are the typical limits for mercury switch contacts?

  1. Hundreds of amps and 600 V
  2. Thousands of amps at high voltage
  3. No more than a few amps and 120 V
  4. Milliamps at 5 V only
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Correct answer: No more than a few amps and 120 V

Large mercury contacts are not practical to build.

Source: Lessons in Electric Circuits IV: Digital (Kuphaldt), 4.2: Switch Contact Design

Practice wiring and components

Questions last reviewed: 18 October 2026