Key Terms

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

Branch circuit: The circuit conductors between the final overcurrent device protecting the circuit and the outlets.

Cabinet: An enclosure designed either for surface or flush mounting, and fitted with a frame, mat, or trim in which a swinging door or doors may be hung.

Dead-front: The term usually applies to electrical panels in which the front or accessible part is insulated from line voltage and can be operated without receiving an electric shock.

Disconnecting means: A device, 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."

Enclosure: The case or housing of an apparatus, or the fence or walls surrounding an installation, to prevent personnel from accidentally contacting energized parts or to protect the equipment from physical damage.

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.

Guarded: Covered, shielded, fenced, enclosed, or otherwise protected by means of suitable covers, casings, barriers, rails, screens, mats, or platforms to remove the likelihood of approach to a point of danger or contact by persons or objects.

Overload: Operation of equipment in excess of normal, full load rating, or of a conductor in excess of rated ampacity which, when it persists for a sufficient length of time, would cause damage or dangerous overheating. A fault, such as a short circuit or ground fault, is not an overload.

Qualified Person: One familiar with the construction and operation of the equipment and hazards involved.

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.

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