As a result, exposure may be prolonged, causing severe burns. Generally, the higher the voltage and amperage, the greater the damage from either type of current. The strength of electrical current is measured in amperes. The maximum current that causes arm muscles to contract but still allows the hand to let go of the electric source is appropriately called the let-go current. About 300 to 500 milliamperes of direct current is required to have the same effect.
Resistance is the ability to stop or slow the flow of electrical current.
Most of the body's resistance is concentrated in the skin and depends directly on the skin's condition. The average resistance of dry, healthy skin is 40 times greater than that of thin, moist skin. When the skin is punctured or scraped or when current is applied to moist mucous membranes such as the mouth, rectum, or vagina, the resistance is only half that of moist, intact skin. The resistance of a thick, callused palm or sole may be 100 times greater than that of thinner areas of skin. As electrical current passes through the skin, much of its energy may be released at the surface because it encounters resistance there.