Raceway - Any channel designed for holding wires, cables, or busbars, and, unless otherwise qualified in the Rules of Code, the term includes conduit (rigid and flexible, metal and nonmetallic), electrical metallic and nonmetallic tubing, underfloor raceways, cellular floors, surface raceways, wireways, cable trays, busways, and auxiliary gutters.
Radial Feed - One primary bushing per phase.
Radio-Influence Voltage (RIV) - A high frequency voltage, generated by all sources of ionization current, that appears at the terminals of electric power apparatus or on power circuits.
Ratio - A reference to either the turns ratio or the voltage ratio of a transformer.
RE Conduit - see definition for Conduit.
Reactance - A component of impedance produced by either inductance or capacitance in an ac circuit.
Reactor - A device for introducing inductive reactance into a circuit for motor starting, operating transformers in parallel, and controlling current.
Readily Accessible - Capable of being reached quickly for operation, renewal, or inspection, without requiring those to whom ready access is a requisite to climb over or remove obstacles or to resort to portable ladders, chairs, etc.
Receptacle - One or more female contact devices, on the same yoke, installed at an outlet for the connection of one or more attachment plugs.
Recovery Voltage - The voltage potential established across the open electrodes of an overcurrent protection device after clearing the circuit at a current zero; a term used to designate the voltage impressed by the circuit upon the interrupting device after interruption of the current at or about the time of a natural current zero.
Recreational Vehicle - a structure designed to provide temporary living accommodation for travel, vacation, or recreational use and to be driven, towed, or transported. Except for fifth-wheel trailers, it has an overall length not exceeding 12.5 m and an overall width not exceeding 2.6 m, where the width is the sum of the distances from the vehicle centreline to the outermost projections on each side. These dimensions exclude safety-related equipment such as side safety and warning lights and entry and exit handholds. Also excluded are water spray suppression attachments, load-induced tire bulge, and equipment used to secure cargo on a vehicle. These excluded items are allowed to extend not more than 100 mm when the vehicle is folded or stowed for transit. For a fifth-wheel trailer the maximum overall length is 11.3 m taken from the rear extremity to the front of the main body, measured at the floorline. Such structures include travel trailers, slide-in campers, camping trailers, motor homes, and fifth-wheel trailers:
Recreational Vehicle Park - An area of land designed to accommodate recreational vehicles and park model trailers.
Reduced Capacity Tap - Tap that is not designed to deliver the rated capacity of the transformer.
Reference Current (Iref) - The reference current is the peak value of the resistive component of a power frequency current high enough to make the effects of stray capacitance of the equipment negligible. This current level shall be specified by the manufacturer.
Reference Voltage (Vref) - The lowest peak value independent of polarity of power frequency voltage, divided by the square root of 2, required to produce a resistive component of current equal to the reference current of the equipment or element, i.e., the reference voltage of a multi-unit arrester is the sum of the reference voltages of the series units. The voltage level shall be specified by the manufacturer.
Relocatable Structure - A factory-built unit for use without a permanent foundation.
Remote Control Circuit - Any electrical circuit which controls any other circuit through a relay or an equivalent device.
Repellent used as a Suffix (such as moisture-repellent) - A material constructed, treated, or surfaced so that liquid will tend to run off, and cannot readily penetrate the surface.
Residential Occupancy - The occupancy or use of a building or part thereof by persons for whom sleeping accommodation is provided but who are not harboured or detained to receive medical care or treatment or are not involuntarily detained.
Resistant used as a Suffix (such as absorption-resistant, moisture-resistant, etc) - Material constructed, protected, or treated so that it will not be injured readily when subjected to the specific material or condition.
Resistor - Any device of material that limits the flow of current when voltage is applied.
Resonance - A state in which the capacitance and the inductance values in a circuit are equal (net reactance is equal to zero) and the only quantity left is resistance.
Resonant Frequency - Frequency at which the voltage and the current at the input terminals are in phase. Reactance is equal to zero.
RMS Line Current - The square root of the average of the squares of all the instantaneous current amplitudes occurring during one cycle.
Routine Tests - Test made by the manufacturer on every device or representative samples, or on parts or materials, as required, to verify that the product meets the design specifications.
|Source: Canadian Electrical Code and National Electrical Code|