Electrical Current Properties

An arc flash typically occurs in equipment using intense electrical current. The human body, however, has a very limited ability to deal with electrical current. Because of this, arc flash presents the risk of fatal electric shock.

Electric shock occurs when a part of a person's body completes an electrical circuit. This can occur when energized components at two different potentials, such as a live and ground wire, are touched at the same time. The level of danger posed by an electric shock depends on the nature of the current and how it moves through the body. The duration of the electric shock also determines the extent of the damage.

A shock that moves across the chest or through the head is typically more damaging than current that moves only through limbs. Through any route, the less time the current flows through the body, the less damage it does.

Note that contact with electrical equipment is not required for your body to become part of a circuit; in an arc flash, current moving through the open air can cause electric shock.

The human body's resistance to an electrical current varies from person to person and fluctuates based on internal/external moisture, as well as exposed sub-epidermal tissue (broken skin).

From hand to hand, the human body provides about 10,000 ohms of resistance on the high side and as little as 1,000 ohms of resistance to an electrical current.

To learn more about Arc Flash Safety visit our OSHA Construction Arc Flash Safety Online Training web page.