Question

Before working on a power transmission line, experts will touch the line with the back of the hand as a final check that the voltage is zero. Why the back of the hand?

a) The back of the hand is more sensitive.

b) The palm is more prone to burns.

c) To avoid accidentally grasping the line.

d) The back of the hand has higher resistance.

Answer 1

The back of the hand is used to touch a power line to avoid involuntary muscle contraction that could lead to grasping the wire. This is a safety measure when verifying that power lines have no voltage.

Step-by-step explanation:

Before working on a power transmission line, experts will touch the line with the back of the hand as a final check that the voltage is zero. The primary reason for using the back of the hand is c) To avoid accidentally grasping the line. If there happened to be voltage on the line, touching it with the palm or fingers could cause an involuntary muscle contraction, leading to grasping the wire, which would prolong the exposure to electric shock and increase the risk of injury.

It's also important to note that working with high-power circuits, experts often work "one-handed" or "keep one hand in their pocket" to minimize completing a circuit across the heart which could be fatal. Furthermore, precautions are taken to minimize electric power losses along transmission lines, such as transmitting power at high voltage over long distances to reduce currents and resulting losses due to resistance in the lines.