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64 Cards in this Set
- Front
- Back
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What is the purpose of the National Electrical Code (NEC®)?
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To safeguard personnel and
buildings only |
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A conductor used in connecting equipment in the circuit of a wiring system to a grounding electrode or electrodes is described by what
term? |
Grounding conductor
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A circuit conductor that is grounded intentionally is described by what
term? |
Grounded conductor
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What term means connected to the earth or to some other conducting
body that serves in place of the earth? |
Grounded
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What common wiring system is used in housing to provide 110/220volt services?
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Three-wire, single-phase
system |
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A four-wire electrical system typically has how many (a) hot wires and (b) neutral wires?
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(a) Three (b) one
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What device is installed as part of the service entrance to record power consumption?
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Wattmeter
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The service entrance must provide a means for disconnecting the service
entrance conductors from the interior building circuits. |
True
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Overcurrent protective devices are required for many types of electrical circuits; however, they are not required for service conductors in
conjunction with the service disconnects. |
False
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Which of the following overcurrent protection devices are permitted with service entrances?
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1. Fuse blocks 2. Circuit breakers 3. Knife-blade switches
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A metal underground water pipe may be used as the primary grounding electrode when it is in direct contact with the earth for a minimum of how many feet?
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10
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What type of wiring is used most frequently for interior wiring jobs?
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Solid No. 12 AWG
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What is the current-carrying capacity of each conductor when you have ten No. 12 AWG conductors in the same conduit?
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17.5 A
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What information is shown on the outer jacket of nonmetallic cable?
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1. Manufacturer’s name or trademark
2. Maximum working voltage 3. Wire size and cable type |
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When a length of 7/8-inch-diameter Romex cable is run in a Quonset hut, it is necessary to make some 90-degree bends. What is the minimum radius of a bend, in inches, for this cable?
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4.4
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A conductor must be provided free air space in a box for what primary reason?
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So heat does not build up
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Conductors that run through or terminate in an outlet box are counted in what manner?
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Each conductor that terminates
is counted as one; internal grounding wire and fixture wires are not counted |
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What causes an “A” bracket to make an extremely strong mounting?
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It is nailed from both front and side
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In houses, what is the most popular installation height for receptacle outlet boxes?
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One foot from the floor line
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What is the normal mounting height, in inches, for switch boxes
and outlet boxes in a laundry room? |
48
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What are the stages for installing nonmetallic cable?
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Roughing in and finish work
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The electrical print requires that you run a concealed cable perpendicular in a floor joist above a basement
floor. How should the cable be run? |
Through bored holes in the floor joist or in notches cut into the floor joist
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When roughing in, what amount of cable, in inches, should you leave in the box to attach devices?
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6
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What type of electrical grounding consists of connecting all exposed noncurrent-carrying metal parts to earth?
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Equipment
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In remote-control wiring systems, low-voltage transformers reduce 120 volts to what usable voltage?
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24 V
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A conduit threading die is used for which of the following reasons?
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To make a tapered thread on conduit
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The solvent-welding technique for joining PVC conduit is superior
because the finished joints are |
waterproof and vaporproof
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What number of 90-degree bends are permitted in a run of conduit?
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Four
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What type of bender makes a full 90-degree bend in conduit with a
single motion? |
One-shot
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The distance from the back of a 90degree bend to the end of the conduit is referred to by what term?
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Stub-up
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Two adjacent 90-degree bends in the same conduit make up what type of bend?
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Back-to-back
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Offset bends are used to avoid contacting a part of the structure or to bring the conduit out from the structure to match a knockout in a box or panel.
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True
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The practice of taking small bites to reduce kinking or crimping should be used when you are bending with what type of bender?
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Hickey
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Generally, what is the smallest size raceway that can be installed?
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1/2 in.
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EMT and IMC conduit must be supported (a) within how many feet of each box and (b) at intervals of how many feet thereafter?
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(a) 3 (b) 10
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Flexible metal conduit must besupported within how many inchesof each box or fitting?
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12
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A CE finds that a run of conduit between boxes will have five 90degree bends. What, if anything, should the CE do to complete the conduit run?
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Use a Condulet instead of one
of the bends |
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According to the NEC®, the bends in one conduit run cannot exceed how many degrees?
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360°
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Which of the following tools is/are required to restore a hook on the
end of a fish tape? |
A pair of pliers and a torch
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What advantage is there when you pull conductors from the second floor of a structure to the first floor?
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The weight of the wires helps
in the pull |
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Which of the following tools makes a good handle for pulling a fish tape?
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Side-cutting pliers
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What condition occurs when too many conductors have been installed in the conduit?
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Overheating occurs and the
conductor ampacity decreases |
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What explosion hazard classification identifies the most hazardous condition?
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Class 1, division 1
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Where is the most hazardous space inside a gasoline station?
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Within 18 inches of the floor
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Not counting the main, what maximum number of overcurrent devices are authorized for lighting and appliance panelboards?
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42
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A single overcurrent device in a panelboard must not exceed what percentage of its capacity?
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80%
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In a three-phase panelboard, what phase, if any, should be clearly marked?
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B
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What is the maximum voltage, if any, of a knife-blade fuse?
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600 volts
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What are the three classes of circuit breakers?
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Thermal, magnetic, and combination thermal-magnetic
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Which of the following circuits in a home requires the use of a GFCI
type of circuit breaker? |
120-V/20-A receptacles in bathrooms
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What is the purpose of balancing the load on a panelboard?
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To reduce voltage drop
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What are the three types of shorts or grounds?
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Solid, partial, and floating
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Which of the following meters can NOT be used on an energized circuit?
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Ohmmeter
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When choosing continuity testing equipment, it is of primary importance that you select
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low-voltage instruments to reduce sparking
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When you take a voltage reading on the neutral side of an inoperative
lamp to ground and you read applied voltage, what condition is indicated? |
An open in the grounded conductor
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What happens to a circuit when a resistor is put in series with the circuit?
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The current decreases, causing the lamps to be dimmer
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When you are operating a lamp below the rated voltage, lamp life is
decreased with a sacrifice in light output. |
False
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Made of special glass with high resistance to thermal shock.
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Hard Glass
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Installed where lamp replacement costs are high.
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Long Life
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Lasts twice as long as regular general-service incandescent lamps.
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Quartz-Iodine
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A ballast is required in a fluorescent lamp for what reason?
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To limit current and supply proper voltage
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Which of the following conditions can cause incandescent lamps in a lighting circuit to burn out frequently?
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1. High voltage 2 Excessive vibration 3. Wrong rating for conditions
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A fluorescent lamp is slow to light after the switch is turned on. If the line voltage is proper, what action should you take to correct the condition?
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Replace the starter
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What is the best indication that a fluorescent lamp is nearing the end of its useful life and will soon burn out?
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It is flashing ON and OFF
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