Electrical: NEC Level 4, Entire Second Semester
Heating cable for snow-melting is typically installed in a serpentine pattern with loops spaced at _____.
1 foot (30 cm) on center
How far below the finished surface should snow-melting and anti-icing systems be installed?
1-1/2 to 2 inches (4 to 5 cm)
The power rating of a voltage regulator should be based on the maximum power outputcapability of the tester multiplied by a factor of about _____.
1.3
In general, how much endplay should ball-bearing motors have?
1/32" to 1/16"
For floating structures that are installed to rise and fall in response to the water level without lateral movement, the electrical datum plane is 30" above the point at which the floating structure touches the water and a minimum of how many inches above the deck level?
12"
Which of the following is the recommended abrasive cloth used to clean cable during a splice?
120-grit abrasive cloth
For outdoor electric de-icing installations, branch circuits and overcurrent devices supplying the equipment shall be sized at not less than what percentage of the total heater load?
125%
Wall-mounted underwater luminaires must be installed so that the top of the lens is at least how many inches below the water level?
18
The recommended minimum polarization index for an AC motor is _____.
2.0
The polarization index is commonly used for motors that exceed _____.
200hp
The maximum branch circuit rating for footlights, border lights, and proscenium sidelights when using standard lampholders is _____.
20A
The main overcurrent protective device that feeds a marina must have ground-fault protection of no more than _____.
30mA
NEMA's usual service conditions include a frequency variation of not more than what percentage of the nameplate frequency?
5%
Any fixed or stationary electric sign that is installed within a fountain must be at least how many feet inside the fountain, as measured from the outside edge of the fountain?
5'
Unless there is a permanent barrier installed between the receptacle and a storable pool, a receptacle cannot be located any closer to a storable pool than _____.
6 feet
Proof tests are made at what percentage of the original factory voltage?
60%
Heater elements on electric pool-water heaters must be subdivided into loads not exceeding 48A each and be protected by overcurrent protective devices not greater than _____.
60A
According to the NEC®, cables on agricultural buildings must be secured within how many inches of any box, cabinet, or fitting to which they connect?
8"
Acceptance testing calls for a maximum value of what percentage of the factory test voltage?
80%
How are future service connections handled when installing heat tracing on domestic hot-water supply systems?
A service loop of extra heating cable is provided at connections.
Which of these devices can retain a high-voltage charge after power has been removed?
Capacitors used in motor circuits
Which of the following termination classes is the only one that provides a seal against external elements?
Class 1
Which of the following is the best instrument for testing for a grounded coil?
Continuity tester
To finish a splice and ensure complete protection, it should be covered with how many layers of vinyl electrical tape?
Four
Which of the following principles states that heat is created in one place and carried to another by means of air or water?
Heat-transfer principle
When conducted properly, which of the following will indicate faults such as cracks, discontinuity, thin spots, and faulty terminations?
Hi-pot test
Thermostats with bimetal sensing elements typically use a combination of copper or brass and _____.
Invar®
Which of the following is an approved wiring method allowed in fire-rated construction?
Metal-clad cable
When refrigeration compressors are driven by conventional (nonhermetic) motors, the motors and controls are subject to the requirements in _____.
NEC Article 430
In agricultural buildings that require equipotential planes, the equipotential plane must be bonded to the grounding system with a bare or insulated solid copper wire no smaller than _____.
No 8 AWG
Assuming that a worker is qualified to do a job and is otherwise an effective craft professional, which of the following could be a reason for turnover for such a worker?
Not being given any opportunity for advancement
The thermostat terminal that connects to the reversing valve control in a heat pump is _____.
O
The form used to report work-related injuries and illnesses is _____.
OSHA Form 300
Materials typically used for cable jackets include neoprene, lead, and _____.
PVC
Which of the following may be used to detect unusual bearing noise during rundown when the motor is powered down?
Stethoscope
Which of the following statements regarding the consequences of willful safety violations is true?
Superintendents and crew leaders can be held financially and criminally liable.
Which of the following describes a finned air-over motor that powers and is cooled by the slipstream from a large fan?
TEAO motor
Which of the following is used to check the rotating speeds of motors?
Tachometer
Which of the following occurs as soon as a heating thermostat is closed?
The inducer fan starts.
Which of the following is an NEC Article 427 requirement for the installation of electrical heat tracing cables on pipelines and vessels in unclassified areas?
The presence of electric heating equipment must be identified using permanent caution signs or markings at the specified intervals.
Which of the following is an example of an external analog device?
Thermistors
Which of the following is true with regard to fixed stage switchboards?
They are permitted to supply both stage and non-stage equipment.
Which of the following is not a factor in determining the appropriate type of heating cable for a pipe heat-tracing application?
Type of process fluid
On a roof de-icing system, secure cables to each other using _____.
UV-resistant cable ties
Which of the following best describes continuity monitoring?
Verifies that voltage is present at the end termination of a heat-tracing cable run
A knee in a leakage current-versus-voltage plot indicates a _____.
breakdown current
To eliminate air voids when preparing a splice, pencil the insulation and then _____.
buff it using abrasive cloth
Two methods used to provide stress control for medium-voltage cable terminations are geometric and _____.
capacitive
If a mercury thermostat seems out of adjustment, the first thing to do is _____.
check for accurate leveling
The component labeled 2 in Figure 2 is a(n) _____.
controller
A suitable connector for medium-voltage cable splices is a compression or _____.
crimp type
Automatic changeover thermostats have a minimum interlock setting, also known as the _____.
deadband
Multi-stage thermostats provide energy savings by cycling on stages of heating or cooling based on _____.
demand
The temperature at which a liquid first condenses when vapor is cooled is known as the _____.
dew point
As the temperature surrounding a self-regulating heating cable decreases, the _____.
electrical resistance decreases
Absorption current consists of polarization current and _____.
electron drift
The component labeled 7 in the figure above is a(n) _____.
end seal
NEC Section 555.19(A)(1) states that proper shore power receptacles for marinas shall be _____.
equipped with strain relief for the cable when it is plugged in
The loss of a single phase of a polyphase motor can cause _____.
failure of the remaining phase windings
Electric heat tracing of pipe is done for freeze protection and _____.
for temperature maintenance of the process fluids
A quick test that can be made to determine if an installation is good is known as a(n) _____.
go/no-go test
Splices made with conductors of different sizes can be most easily accommodated using a(n)_____.
heat-shrink kit
OSHA regulations require that employers _____.
identify and keep records of safety hazards
If a lockout relay becomes defective, it should be replaced with an exact duplicate, sometimes called a(n) _____.
impedance relay
Companies traditionally offer craft-professional training _____.
in a hands-on setting, where they learn from an experienced worker
In both new and retrofit construction situations, a hydromassage or whirlpool tub must have power supplied by a(n) _____.
individual branch circuit
The useful life of a squirrel cage induction motor depends largely upon the condition of its _____.
insulation
A conventional thermostat should not be thrown into the regular trash because it _____.
may contain mercury
Connecting a 120V heating cable to a 240V circuit will _____.
melt the cable
Which of the following factors affects the frequency and thoroughness of motor maintenance and testing?
nature of service
A freezestat is a _____.
normally closed bimetal switch
To extend the melting time of a snow-melting system, controllers can use a(n) _____.
off-delay timing function
If two separate receptacles having different voltages and amperage ratings are installed in a single boat slip, the total load calculation must include _____.
only the receptacle with the higher VA demand
Self-regulating cables are referred to as _____.
parallel resistance heating cables
Insured costs for occupational injuries or deaths include _____.
pensions for dependents
In an air-to-air heat pump, defrost is accomplished by _____.
placing the unit in the cooling mode
When installing heating cable, fasten the cable to the pipes using fiberglass tape or _____.
plastic cable ties
The component labeled 1 in the figure above is a(n) _____.
power connection
The purpose of the defrost cycle in a heat pump is to _____.
prevent ice buildup on the outdoor coil
An autotransformer is one of the methods used to _____.
reduce startup current
NEC Article 440, Part V covers _____.
requirements for motor compressor controllers
The frequency of motor lubrication depends on the type of bearing, motor application, and _____.
service environment
The main way for crew leaders to encourage crew safety is to _____.
set a good example for them
A carnival ride properly powered through a disconnect switch within 6 feet (1.8 m) of the operator can also be opened from the operator's console using a _____.
shunt trip
Bearing misalignment within a motor can result when one or two of the mounting feet of a motor are spaced away from an uneven mounting surface and are then anchored down against the surface without proper shimming. This condition is referred to as _____.
soft foot
The most effective approach to the inability of two employees to work together would be to _____.
speak directly to the individuals and to others to learn what the problems are
According to NEC Article 424, embedded floor heating cable may be spliced with _____.
splices identified in the manufacturer's instructions
When two or more wired partitions are electrically connected together, the cord must be terminated at an attachment plug-and-cord connector equipped with a _____.
strain relief device
The tubing that carries heat-laden refrigerant gas from the evaporator to the compressor is known as the _____.
suction line
The component labeled 6 in the figure above is a(n) _____.
tee kit
Which of the following qualifies as an assembly occupancy?
the auditorium of a civic center
Footlights in a stage that are designed to disappear into a storage recess when not in use must be designed so that _____.
the power supply is automatically disconnected when the lights are retracted
When delegating, the crew leader should make sure the crew member understands what to do and _____.
their level of responsibility
A device that uses dissimilar metals to control electron flow is known as a(n) _____.
thermocouple
Individual freestanding partitions or groups of them secured together can be powered using a single flexible cord, provided that there are no more than _____.
thirteen 125V, 15A receptacles
To increase furnace efficiency, the startup of the furnace blower is delayed using a _____.
time delay relay
Prohibitions on the abuse of drugs apply _____.
to any inappropriate use of drugs or other substances that cause impairment
In temporary installations, single insulated feeder and branch circuit conductors may be used to supply power for temporary testing, emergencies, experiments, and developmental work where accessible _____.
to qualified persons only
Insulation must protect from flashover damage and _____.
tracking damage
To transmit information, systems using power-line carrier technology make use of _____.
wiring
