Electrical Definitions


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Electrical Definitions

Letter - R


An enclosed channel of metal or nonmetallic materials designed expressly for holding wires, cables, or busbars, with additional functions as permitted in this Code. Raceways include, but are not limited to, rigid metal conduit, rigid nonmetallic conduit, intermediate metal conduit, liquidtight flexible conduit, flexible metallic tubing, flexible metal conduit, electrical nonmetallic tubing, electrical metallic tubing, underfloor raceways, cellular concrete floor raceways, cellular metal floor raceways, surface raceways, wireways, and busways.



Constructed, protected, or treated so as to prevent rain from interfering with the successful operation of the apparatus under specified test conditions.



Constructed or protected so that exposure to a beating rain will not result in the entrance of water under specified test conditions.



The rating of an electrical device includes (1) the normal r.m.s. current which it is designed to carry, (2) the normal r.m.s. volt-age of the circuit in which it is intended to operate, (3) the normal frequency of the current and the interruption (or withstand) rating of the device. (See Interrupting Rating)



Opposition to the flow of alternating current. Capacitive reactance is the opposition offered by capacitor, and inductive reactance is the opposition offered by a coil or other inductance.


Reactive Factor

The ratio of the reactive volt-amperes to the apparent power.


Reactive Volt Amperes

The product of the voltage, current and the sine of the phase difference between them. Expressed in vars.


Readily Accessible

Capable of being reached quickly for operation, renewal, or inspections without requiring those to whom ready access is requisite to climb over or remove obstacles or to resort to portable ladders, and so forth.



A receptacle is a contact device installed at the outlet for the connection of an attachment plug. A single receptacle is a single contact device with no other contact device on the same yoke. A multiple receptacle is two or more contact devices on the same yoke.


Receptacle Outlet

An outlet where one or more receptacles are installed.



An electrical device used to change AC power into DC power. A battery charger is a rectifier.



A device which is operative by variation in the conditions of one electric circuit to effect the operation of other devices in the same or another electric circuit.


Remote-Control Circuit

Any electric circuit that controls any other circuit through a relay or an equivalent device.



An adjustable resistor constructed so that its resistance may be changed without opening the circuit.



The rotating member of a generator.