The Current Story
2. How Current Affects Your Body
Okay, let’s get down to the real heart of the matter: current. Current, measured in amps, is what actually causes the physiological effects of electric shock. Even small amounts of current can be dangerous, causing muscle contractions, pain, and even death.
The generally accepted rule of thumb is that currents as low as 1 milliamp (mA) can be felt. Around 10 mA can cause painful shock and involuntary muscle contractions — that’s why you might not be able to let go of something that’s shocking you. Currents above 100 mA are considered lethal, as they can disrupt your heart’s rhythm and cause ventricular fibrillation (a fatal heart condition).
Now, here’s where things get interesting: the amount of current that flows through you depends not only on the voltage but also on your body’s resistance. Resistance is measured in ohms. Dry skin has a relatively high resistance, while wet skin has a much lower resistance. That’s why you’re more likely to get a shock if you’re wet.
So, if you come into contact with 40 volts and your skin is dry, your resistance might be high enough to limit the current to a safe level. However, if you’re sweaty or standing in water, your resistance will be much lower, and a dangerous amount of current could flow through you. That’s why working with electricity near water is always a bad idea!