Electrical Engineering Concepts

• To mount to a hollow tile wall, use toggle bolts
• 60 cycle frequency travels 180 degrees in 1/120 seconds
• Electric pressure or electromotive force is measured in Volts
• A fitting is part of a wiring system that performs a mechanical function
• A 15 ohm resistance carrying 20 amperes of current uses 6000 watts of power

Grounding Conductors

• Grounding conductors running with circuit conductors may be uninsulated
• Grounding conductors running with circuit conductors may be a continuous green, if covered
• Grounding conductors running with circuit conductors may be continuous green with yellow stripe, if covered

Considerations for Judging Equipment

• Wire-bending and connection space of judging equipment must be evaluated
• Arcing effects of judging equipment must be evaluated
• Electrical insulation of judging equipment must be evaluated
• One-half cycle is related to an alternation
• Locknuts are sometimes used in making electrical connections on studs to prevent loosening under vibration
• To sharpen an electrician's knife, use a carborundum stone
• An electrician should never strike a hardened steel surface with a hardened steel hammer to prevent a safety hazard
• The best type of saw to use to cut a 3" diameter hole through 1/2" plywood is a saber saw
• It's permissible to install direct current and alternating current conductors in the same outlet box if insulated for the maximum voltage of any conductor
• An overcurrent protective device with a circuit opening fusible part that is heated and severed by the passage of overcurrent is called a fuse
• A corroded electrical connection increases the resistance at the connection
• A branch circuit can never be supplied through an autotransformer
• When soldering a joint, the flux is used to keep the surface clean
• A commutator is a device for causing alternating currents generated in the armature to flow in the same direction in the external circuit
• Hysteresis is the lagging of magnetism, in a magnetic metal, behind the magnetizing flux, which produces it
• Effective voltage is 70.7% of the maximum (peak) voltage
• Rheostats and potentiometers are types of variable resistors
• A magnetic field is created around a conductor whenever current flows in the conductor
• One million volts is equal to 1 megavolt
• Minimum size service permitted by the Code for a resistance is 100 amps
• The greatest voltage drop in a circuit will occur when the current flow is greater
• Friction is the least used method of producing EMF
• Tinning rubber insulated twisted cable is done to prevent chemical reactions between the copper and the rubber
• Varying duty is a type of service with wide variations in load and time intervals
• The voltage per turn of the primary of a transformer is the same as the voltage per turn of the secondary
• An electrical timer switch for lighting is normally connected in series with the lighting circuit being controlled
• To check voltage to ground, you would check from the breaker to the cabinet, hot to neutral, or the breaker to the grounding terminal
• Three horsepower is equivalent to 2238 watts
• To adjust the voltage generated by a constant speed DC generator, you would change the field current
• An electrician in the industry would first check the inductive load to correct a low power factor
• Frequency is measured in Hertz
• An advantage of a 240-volt system compared with a 120-volt system of the same wattage is a reduced voltage drop
• For an adjustable trip coil rated at 5 amps on a 200-amp switch, to have the switch trip at 120 amps, set the trip coil at 3 amps
• For screw shell devices with attached leads, conductors attached to the screw shell should be white or gray
• It is generally not good practice to supply lights and motors from the same circuit because lamps for satisfactory service must operate within closer voltage limits than motors
• The LB fitting, and LR fitting is/are classified as a conduit body
• The power factor of an incandescent light bulb would be unity
• The permanent joining of metallic parts to form an electrically conductive path is known as bonding
• To solve series-parallel circuits, reduce to its simplest form
• The location of a wall receptacle outlet in the bathroom of a dwelling is 36" of outside edge of basin
• Voltage drop in a wire is a percentage of the applied voltage
• When conduit or tubing nipples having a maximum length not to exceed 24" are installed between boxes they shall be permitted to be filled 60% of its total cross-sectional area
• The voltage lost across a portion of a circuit is called the voltage drop
• Mandatory rules of the Code are identified by the word "shall"
• The ampacity of a conductor would be affected most by temperature
• A type of motor that will not operate on DC is the squirrel cage motor
• When mounting electrical equipment, do not use wooden plugs driven into holes in masonry, concrete, or plaster
• A set of lights switched from three different places can be controlled by two 3-way and one 4-way switches
• A lighting fixture to be controlled independently from two locations requires a single-pole, double throw
• When re-routing conduit, increase the wire size if the distance is greater, in order to compensate for voltage drop
• Something constructed or protected that exposure to the weather will not interfere with successful operation is Weather proof, Raintight, and Watertight
• To cut holes in masonry, a star drill is most commonly used
• In the term "10-32" for machine screws, "32" refers to threads per inch
• Continuity of an electrical circuit can be determined with a bell and battery set
• Continually overloading a conductor is a poor practice because the insulation deteriorates
• Wire connections should encircle binding posts in the same manner the nut turns to tighten
• It is not a safe practice when lifting heavy items to keep lifting a heavy object until you get help
• Electrical energy can be generated
• A circuit breaker that has purposely introduced into it a delay in the tripping action and which delay decreases as the magnitude of the current increases is an inverse time circuit breaker
• Listed or labeled equipment shall be installed, used, or both, in accordance with the listing or labeling, with the equipment from the manufacturer
• Flexible cords and cables shall be protected by fittings or bushings where passing through holes in covers, outlet boxes, or similar enclosures
• A type of AC motor that runs at a constant speed is a synchronous motor
• In general, motors are designed to operate in a maximum ambient temperature of 40°C unless specifically designed for a higher temperature
• Not readily accessible to persons unless special means for access is isolated
• When an ammeter is disconnected from an in-service current transformer, the secondary terminals of the current transformer must be shorted
• Voltage in a generator is produced by cutting lines of force
• A laminated pole is one built up of layers of iron sheets, stamped from sheet metal and insulated
• Wire connectors are generally classified as Thermal or Pressure

Service Conductors

• The service conductors from the service equipment to the outside are neither service drop, service-entrance conductors, nor service equipment
• To determine if a raceway is truly vertical, use a level
• A conduit body is a cast fitting (FD or FS box)
• A sealtight enclosure, A "LB" or "T', or similar fitting may be used for conduit
• Never approach a victim of an electrical injury until sure the power is turned off
• The definition of ampacity is how much current in amperes a conductor can carry continuously under the conditions of use without exceeding its temperature rating
• The most important reason for using a condulet-type fitting instead of bending a same inch conduit is to make wire pulling easier
• Oil is used in many large transformers to cool and insulate the transformer
• Cutting fluid is used when threading conduit is to improve the finish of the thread
• Critical burns are potentially life-threatening, disfiguring, and disabling
• A rubber insulation advantage is that it does not absorb much moisture
• The frame of a motor is usually positively grounded to protect against shock
• For a 10:1 step-down transformer with 20,000 primary turns, the secondary should have 2000 turns
• A battery operates on the principle of electrochemistry
• A rigid conduit connecting to an outlet box should have a locknut on the outside and a bushing on the inside
• A DC motor has a wide speed range
• The least important thing in soldering two conductors together is to use plenty of solder
• If the end of a cartridge fuse becomes warmer than normal, tighten the fuse clips

AC Circuits

• In an AC circuit, the ratio of power in watts to volt-amps is the power factor
• Solid wire is preferred because can be "shaped" better
• When working near acid storage batteries, take extreme care to avoid sparks and potential explosions
• The reason for grounding the frame of an electric hand tool is to prevent the frame from becoming alive to ground
• Use bushing to protect conductors from abrasion at box entry
• If a transformer's primary is 480V and secondary is 240/120V, the secondary wire is larger
• Voltage leads the current is when inductive reactance exceeds capacitive reactance
• When the ground resistance exceeds the allowable value of 25 ohms, the resistance can be reduced by Paralleling ground rods, by Using a longer ground rod, Using a larger diameter ground rod, Chemical treatment of the soil
• If a low resistance is connected in parallel with a higher resistance, the combined resistance is always less than the low resistance
• Tapered reamer is used for reaming the ends of rigid conduit after it is cut
• The total opposition to current flow in an AC circuit expressed in ohms is known as Impedance
• To convert AC to DC, use a rectifier
• Standard branch circuits apply to those with two or more outlets
• To mark a point directly beneath a ceiling point on the floor, use a plumb bob
• The ungrounded conductor can be identified by the color pink flamingo
• "Thermally protected" appearing on the nameplate of a motor indicates that Heat sensing element is installed
• The definition of accessible (wire): Not permanently closed in by the building or structure
• A resistance no point along the floor line in any wall space may be more than six feet from an outlet
• The chemical agent in fire extinguishers to fight electrical fires is CO2
• To define wiring which is not concealed use the word exposed
• With a 120 volt incandescent light bulb operating at 125 volts, the bulb will have a shorter life
• The sum of voltage drop around a circuit equals source voltage per Kirchhoff's law
• Determining a positive wire on a single-phase circuit is an impossibility
• Explanatory material in the Code is characterized by FPN
• A commutator of a generator should be cleaned with fine sandpaper
• A thermocouple will transform heat into electricity
• An instrument to measure electrical energy is a watthour meter
• If two equal resistance conductors are connected in parallel, the resistance of the two conductors is equal to one-half the resistance of one conductor
• When working on a motor, remove the fuses to prevent accidental starting
• A tap tool is used to cut internal threads

Electricity

• Remove the victim from contact by using a dry stick or dry rope
• Do not use a file without a handle because The user may be injured
• Splicing with both rubber friction tape has the purpose of providing extra insulation
• To increase the life of an incandescent lightbulb do so at a lower rated voltage
• The advantage of using a storage battery rather than a dry cell is the storage battery Can be recharged
• The instrument that would prove least useful in testing for opens, grounds, and shorts after the wiring has been completed is the ammeter
• Utilization equipment is equipment which utilizes Electric energy for mechanical, chemical, heating, lighting or similar purposes.
• Receptacles installed on 15 and 20 ampere branch circuits shall be of the grounding type
• Pigtails are used on brushes to make a good electrical connection
• A location classified as dry may be temporarily subject to wetness and dampness
• With two 500 watt lamps connected in series across a 110 volt line draws 2 amperes, the total power consumed is 220 watts
• A voltmeter is connected in parallel with the load
• The poorest conductor of electricity is carbon
• A limit switch is used on a piece of machinery to open the circuit when the Travel reaches a preset limit
• The instrument by which electric power is measured is a wattmeter
• Frequency is determined by the Number of poles and Rotation speed of armature of an alternator
• A fixture that weighs more than pounds 50 shall be supported independently of the outlet box
• Raceways or cable trays containing electric conductors shall not contain Pipe for steam, Tube for air, Pipe for water
• is the resistance at the point of contact of two conductors or one conductor and another surface.
• A premises wiring system whose power is derived from a source is Separately derived
• The phenomenon whereby a circuit stores electrical energy is called Capacitance