What is the minimum electrical current that can be fatal to the human body?

It takes a surprisingly small amount of electrical current to cause fatal injury to the human body. As little as 20 milliamperes (0.02 amperes) flowing through the chest can disrupt the heart's delicate electrical system, potentially causing ventricular fibrillation or cardiac arrest. While higher currents like 500 milliamperes or 1 ampere will cause severe burns and extensive tissue damage, the threshold for a fatal shock starts much lower. This is why strict safety procedures, such as working with one hand behind your back near live circuits, are essential to prevent even minor currents from crossing your heart.