COSC 325 Houston (Electrical) Exam | Questions and Answers

COSC 325 Houston (Electrical) Exam | Questions and Answers Set screw connector box fitting that relies on pressure of a screw against conduit to hold it in place Electrical Connections Soldering: 60% tin, 40% lead, amount of tin determines strength Tape: insulates up to 600 V Wire nuts: hold wires together and has color codes to indicate conductors Splice: twist Grounding Provides a harmless, low-resistance path for electricity to follow. Single phase power permits the potential difference to drop to zero with every change in the direction of current flow Circuit the complete path that an electric current travels along Three phase power a combination of 3 alternating voltage wave forms, each displaced 120 electrical degrees (1/3 of a cycle) apart Transformer A device that increases or decreases the voltage of alternating current Current the flow of electrons Generated Electricity Alternating current (AC) created by power plant generators. Power plants create 3 phase AC A junction box Box used to join several electrical wires into a circuit NM cable "romex" Non-metallic sheathed cable Knockout Round indentation punched into the metal of a box and held in place by un punched narrow strips of metal GFCI receptacle When an existing two-wire, nongrounding-type receptacle is replaced in a location where the CODE requires a GFCI receptacle, it is permitted to be replaced by a ... RMC Conduit Rigid metal conduit, heavy duty. Threaded connections EMT Conduit Electrical metal tubing, very thin walls FMC Conduit Flexible metal conduit, wire is not added until installation is complete Insulator materials Rubber, plastic, air, glass, paper Compression connector Box fitting that firmly secures conduit to a box by utilizing a nut that compresses a ring into conduit Conductor materials a material that easily allows the flow of electricity- metals Power formula E=P/I (Voltage=Power/Current) Circuit Breaker Overcurrent protection device with a mechanical mechanism that manually or automatically opens a circuit when overload or short circuit occurs 3 Phase "high" 480/277V, 3 hot wires, 480="line to line", 277="line to neutral" 3 Phases "Low" 208/120V, 3 hot wires LOTO Lock Out Tag Out Electrical Energy Calculations (kWh) E=PxT Service Panel The main distribution box that receives the electricity and distributes it to various points in the house through branch circuits Amp A unit of electric strength Lumens a measurement of the brightness of light Where is 120/240V, single phase, 3 wire used? Residential, interior lighting wiring What is 120/208V 3 phase 4 wire used for? Providing large amounts of low voltage power Foot Candles; Lux Lumens divided by area How many "hot" wires in single phase power? 2 Incandescent light a filament lamp rendered luminous by electric current; white light Fluorescent Low pressure discharge, ionization of mercury vapor Compact Fluorescent Lamp (CFL) lamp made with one or more small, folded fluorescent tubes and equipped with a screw base. The ballast is a separate control gear or is built into the unit as an integral part of the system Three-way switches Are used where it is desired to control lamps from two different points, as in a stairwell. Four way switch switch used in conjunction with the 3 Way switches to control lights from the three locations Automatic Transfer Switch (ATS) A device that is basically a double throw switch of generally 3-pole connection that will automatically transfer the power from the standby generator to the building circuitry during electrical power failure. Generator A machine that converts mechanical energy into electrical energy