Tap - A connection brought out of the winding at some point between its extremities, usually to permit changing the voltage or current ratio.
TCC (Time Current Curve) - TCCs are a series of points plotted in a curve on log paper describing the current-time reacting characteristics of a current interrupting device. TCCs are a tool used by engineers to determine coordination and correlation of devices.
Temperature Rise - The temperatures increase over ambient due to load.
Temporary Overvoltage (TOV) - A temporary overvoltage is define as an excursion of power frequency voltage above the normal line-to-ground value. Such excursions are of variable magnitude and duration.
Theatre - A building, or any portion thereof, which is used for public, dramatic, operatic, motion-picture, or other performances.
Thermal Cutout - A device affording protection from excessive current, but not necessarily short-circuit protection, and containing a heating element in addition to, and affecting, a fusible member which opens the circuit.
Three Phase Power - Three separate outputs from a single source. There is a phase difference of 120° between any two of the three voltages and currents.
Time Current Curves (TCC) - A series of points plotted in a curve on log paper describing the current-time reacting characteristics of a current interrupting device; a tool used by engineers to determine coordination and correlation of devices.
Time to Impulse Sparkover - The time between virtual zero of the voltage impulse causing sparkover and the point on the voltage wave at which sparkover occurs.
Tracking - Irreversible degradation of surface material from the formation of conductive carbonized paths.
Transformer - A static electrical device which by electromagnetic induction transfers electrical energy from one circuit to another circuit usually with changed values of voltage and current in the process.
Transformer Rated Meter Mounting Device - a meter mounting device with current transformers and with or without test switches mounted in the same enclosure.
Transient - A high amplitude, short duration pulse superimposed on the normal voltage.
Transient Response - The ability of a circuit to faithfully reproduce a transient applied to its input.
Turn Ratio - The ratio of the number of turns in the high voltage winding to that in the low voltage winding.
Type I Nonmetallic Conduit - see definition for Conduit.
Type II Nonmetallic Conduit - see definition for Conduit.
|Source: Canadian Electrical Code and National Electrical Code|