Key Terms

Ampacity: The current, in amperes, that a conductor can carry continuously under the conditions of use without exceeding its temperature rating.

De-energized: Free from any electrical connection to a source of potential difference and from electrical charge; not having a potential that is different from that of the earth.

Disconnecting means: A device, or group of devices, or other means by which the conductors of a circuit can be disconnected from their source of supply. Also referred to as a "disconnecting device."

Energized: Electrically connected to a source of potential difference.

Exposed: Capable of being inadvertently touched or approached nearer than a safe distance by a person. Includes parts not suitably guarded, isolated, or insulated.

Grounded: Connected to the earth or to some conducting body that serves in place of the earth.

Insulated: Separated from other conducting surfaces by a dielectric (including air space) offering a high resistance to the passage of current.

Non-incendive: Equipment having electrical or electronic circuitry that is incapable, under normal operating conditions, of causing ignition of a specified flammable gas-air, vapor-air, or dust-air mixture due to arcing or thermal means.

Qualified person: An individual who has training in avoiding the electrical hazards of working on or near exposed energized parts; an "unqualified person" has little or no such training.

Receptacle: A contact device installed at the outlet for the connection of an attachment plug.

Service: The conductors and equipment used for delivering electrical energy from the serving utility to the wiring system of the premises served.

Voltage, nominal: A nominal value assigned to a circuit or system for the purpose of conveniently designating its voltage class. The actual voltage at which a circuit operates can vary from the nominal within a range that permits satisfactory operation of equipment.

Voltage to ground: For grounded circuits, the voltage between the given conductor and that point or conductor of the circuit that is grounded. For ungrounded circuits, the greatest voltage between the given conductor and any other conductor of the circuit.

To learn more about Electrical Safety visit our Electrical Safety Online Training web page.