Red Seal Electrician Practice
Safety and work practicesQuestion 671 of 1506

Why can low-frequency AC (50 to 60 Hz) be especially dangerous when a hand grips a live conductor?

  1. It causes a long muscle contraction that can freeze the hand to the source.
  2. It causes a single twitch that throws the person clear of the source.
  3. It has no effect on muscles and works only on the skin.
  4. It makes the body resistance rise during contact.
Show answer

Correct answer: It causes a long muscle contraction that can freeze the hand to the source.

Longer contact means a longer exposure to the current.

Source: Lessons in Electric Circuits I: DC (Kuphaldt), 3.2: Physiological Effects of Electricity

Practice safety and work practices

Questions last reviewed: 18 October 2026