03/06/2025
What is more lethal; AC OR DC?
While both AC and DC can be lethal, AC is generally considered more dangerous than DC at the same voltage due to the cyclical nature of AC current, which can lead to more severe muscle contractions and potentially heart fibrillation.
Here's a more detailed explanation:
Current, not voltage, is the killer:
It's the amount of current flowing through the body, not the voltage, that causes harm.
AC's cyclical nature:
AC current oscillates, meaning it flows in one direction and then the other, which can cause muscles to contract and relax, making it harder to let go of a live wire.
DC's constant flow:
DC current flows in one direction, which can cause muscles to lock up, making it harder to let go.
Heart fibrillation:
AC current, especially at frequencies around 60 Hz (common in household power), can interfere with the heart's natural rhythm, potentially causing ventricular fibrillation, a dangerous condition.
"Let-go" threshold:
The current required to cause a person to involuntarily grip a live wire (the "let-go" threshold) is generally lower for AC than for DC.
Frequency matters:
The frequency of AC current also plays a role in its danger. The frequency of 60 Hz, commonly used for household power, is in the range that is most harmful to the human body.
Skin resistance:
Wet or sweaty conditions can significantly reduce the body's resistance to electricity, increasing the risk of shock.
Body fat:
People with higher body fat percentages may experience less severe shocks than those with lower fat percentages, as body fat has a higher resistance to electricity.
Duration of exposure:
The longer a person is exposed to an electric shock, the greater the risk of serious injury or death.
Path of current:
The path the current takes through the body also affects the severity of the shock. For example, a shock that passes through the chest is more dangerous than one that passes through the limbs.
