Factors that Determine Current Levels
As we know, the severity of an electrical shock in the body is determined by several factors that influence the amount of current and the duration of exposure.
The amount of current passing through the body also affects the severity of an electrical shock.
These factors include:
- Voltage. Greater voltages produce greater currents.
- Resistance. Resistance hinders current. The lower the resistance (or impedance in AC circuits), the greater the level of current.
- Body type. Muscle structure also makes a difference. People with less muscle tissue are typically affected at lower current levels.
- Duration. If the shock is short in duration, it may only be painful. A longer shock (lasting a few seconds) could be fatal if the level of current is high enough to cause the heart to go into ventricular fibrillation. Duration is important when you realize that a small power drill uses 30 times as much current required to cause death. However, if the shock is of short duration and the heart has not been damaged, a normal heartbeat may resume after contact with the electricity is eliminated. (This type of recovery is rare.)
- Moisture. Dry skin may have a resistance of 100,000 ohms or more. Wet skin may have a resistance of only 1,000 ohms. Wet working conditions or broken skin will drastically reduce resistance. The low resistance of wet skin allows current to pass into the body more easily and give a greater shock.
- Force. When more force is applied to the contact point or when the contact area is larger, the resistance is lower, causing stronger shocks.
Knowledge Check Choose the best answer for the question.
2-5. Which of the following will result in lower resistance and greater risk of injury when shocked?
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