Electrical final exam 4B
How far below the finished surface should snow-melting and anti-icing systems be installed?
1 1/2" to 2"
Heating cable for snow-melting is typically installed in a serpentine pattern with loops spaced at _____.
1' on center
The power rating of a voltage regulator should be based on the maximum power output capability of the tester multiplied by a factor of about _____.
1.3
For floating structures that are installed to rise and fall in response to the water level on a natural or manmade body of water, the MINIMUM distance of the electrical datum plane above the deck level of the structure is _____.
12"
The abrasive recommended for cleaning cable during a splice is _____.
120-grit abrasive cloth
If a crew of masons is needed to lay 1,000 concrete blocks, and the estimator determined that two masons could complete the job in one eight-hour day, what is the estimated productivity rate for block laying?
125 blocks per hour
For outdoor electric de-icing installations, branch circuits and overcurrent devices supplying the equipment MUST be sized at no less than _____.
125% of the total heater load
NEC Article 427 requires that overcurrent devices supplying electrical heat-tracing cables be sized at no less than _____.
125% of the total heater load
Wall-mounted underwater luminaires must be installed so that the top of the lens is below the water level AT LEAST _____.
18"
The recommended minimum polarization index for an AC motor is _____.
2
When installing snow-melting or anti-icing heating cable, allow an additional _____.
3' for making power connections
NEMA's usual service conditions include a frequency variation of NOT more than _____.
5% of the nameplate frequency
Any fixed or stationary electric sign that is installed within a fountain MUST be at least _____.
5' from the outside edge of the fountain
If lighting units and other appliances are also supplied, the rating of cord- and plug- connected room air conditioners must NOT exceed what percentage of the branch circuit
50%`
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'
Proof tests are made at _____.
60% of the original factory voltage
As long as qualified personnel service the equipment under engineering supervision, a marina may have a MAXIMUM system voltage of _____.
600V
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
Acceptance testing calls for a MAXIMUM value of _____.
80% of the factory test voltage
How are future service connections handled when installing heat-tracing cables 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 termination class is the only one that provides a seal against the external environment?
Class 1
The type of termination that only provides some form of electric stress control for the cable insulation shield terminus is a _____.
Class 3 termination
Which of the following is TRUE regarding luminaires installed in fountains?
Fountain luminaires installed with the lens facing upward must be guarded or listed for use without a guard.
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
Which of the following applications is MOST likely to require the use of a domestic hot-water temperature maintenance system?
High-rise office building
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 (MC) cable
When refrigeration compressors are driven by conventional (nonhermetic) motors, the motors and controls are subject to the requirements in _____.
NEC Article 430
The requirements for pools, spas, and hot tubs can be found in _____.
NEC Article 680
Which of the following factors affects the frequency and thoroughness of motor maintenance and testing?
Nature of service
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
Which of the following is TRUE with regard to heating cable?
Non-heating cable leads exiting the floor must be protected by installing them in conduit.
The thermostat terminal that is connected to the reversing valve control in a heat pump is _____.
O
The form used by employers to report work-related injuries and illnesses is the _____.
OSHA Form 300
Materials typically used for cable jackets include neoprene, lead, and _____.
PVC
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 qualifies as an assembly occupancy?
The auditorium of a civic center
What is the crew leader's responsibility with regard to cost control?
The crew leader must ensure that crew members are aware of project costs and how to control them.
Which of the following is TRUE when designing a pipe heat-tracing system?
The first step is to identify the application.
Which of the following occurs as soon as a heating thermostat is closed?
The inducer fan starts.
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.
On a roof de-icing system, secure cables to each other using _____.
UV-resistant cable ties
An example of a non-monetary award recognizing hard work is _____.
a company jacket
In an air-to-air heat pump, defrost is accomplished by _____.
a) placing the unit in the cooling mode
Endplay adjustment is generally done on large motors with _____.
adjustable bearings
On-site changes in the original design that are made during construction are documented in the _____.
as-built drawings
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
In a cooling system, the heat exchanger where the heat absorbed by the refrigerant is transferred to the cooler outdoor air is known as a(n) _____.
condenser
Which of the following is the BEST instrument for testing for a grounded coil?
continuity tester
The component labeled 2 in the figure (FIGURE 2) provided 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
Absorption current consists of polarization current and _____.
electron drift
The component labeled 7 in the figure provided is a(n) _____.
end seal
NEC Section 555.33(A)(2) 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
Insulation must protect against tracking damage and _____.
flashover damage
To finish a splice and ensure complete protection, it should be covered with _____.
four layers of vinyl electrical tape
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
If excessive vibration is detected in the driven equipment during motor startup, it may be the result of a(n) _____.
imbalanced load
If a lockout relay becomes defective, it should be replaced with an exact duplicate, sometimes called a(n) _____.
impedance relay
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 on 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
A Lovejoy® coupling can be used to reduce _____.
motor to load vibration
The MOST widely used fossil fuel is _____.
natural gas
The type of schedule that shows dependent and critical path activities is the _____.
network schedule
A freezestat is a _____.
normally closed 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
Insured costs for occupational injuries or deaths include _____.
pensions for dependents
When installing heating cable, fasten the cable to the pipes using fiberglass tape, aluminum tape, or _____.
plastic cable ties
The component labeled 1 in the figure provided 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
A limit switch that senses flame outside of the heat exchanger is known as a _____.
rollout switch
The frequency of motor lubrication depends on the type of bearing, motor application, and _____.
service environment
The best 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' (1.8 m) of the operator can also be opened from the operator's console using a _____.
shunt trip
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 using _____.
splices identified in the manufacturer's instructions
When a motor is powered down, unusual bearing noise may be detected by using a(n) _____.
stethoscope
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
A motor's rotating speed can be determined using a(n) _____.
tachometer
The component labeled 6 in the figure (FIGURE 2) provided is a(n) _____.
tee kit
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
Electric heat tracing of pipe is done for freeze protection and _____.
to provide temperature maintenance of process fluids
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
Productivity is defined as the _____.
total amount of material an individual or crew places in a given time
Continuity monitoring is used to _____.
verify that voltage is present at the end termination of a heat-tracing cable run
Systems using power-line carrier technology transmit information through the use of _____.
wiring
The first time a motor is started, it should be allowed to run _____.
without load for 1 hour
