ELECTRICAL: NEC LEVEL 4, ENTIRE SECOND SEMESTER |
QUESTIONS AND ANSWERS | 2026 UPDATE | WITH
COMPLETE SOLUTION
Which of the following principles states that heat is created in one place and
carried to another by means of air or water? Answer - Heat-transfer principle
To increase furnace efficiency, the startup of the furnace blower is delayed
using a _____. Answer - time delay relay
A freezestat is a _____. Answer - normally closed bimetal switch
A device that uses dissimilar metals to control electron flow is known as a(n)
_____. Answer - thermocouple
The purpose of the defrost cycle in a heat pump is to _____. Answer - prevent
ice buildup on the outdoor coil
In an air-to-air heat pump, defrost is accomplished by _____. Answer - placing
the unit in the cooling mode
Which of the following is an example of an external analog device? Answer -
Thermistors
,Which of the following occurs as soon as a heating thermostat is closed?
Answer - The inducer fan starts.
Which of these devices can retain a high-voltage charge after power has been
removed? Answer - Capacitors used in motor circuits
NEC Article 440, Part V covers _____. Answer - requirements for motor
compressor controllers
When refrigeration compressors are driven by conventional (nonhermetic)
motors, the motors and controls are subject to the requirements in _____.
Answer - NEC Article 430
The tubing that carries heat-laden refrigerant gas from the evaporator to the
compressor is known as the _____. Answer - suction line
Connecting a 120V heating cable to a 240V circuit will _____. Answer - melt
the cable
A conventional thermostat should not be thrown into the regular trash because
it _____. Answer - may contain mercury
Thermostats with bimetal sensing elements typically use a combination of
copper or brass and _____. Answer - Invar®
Automatic changeover thermostats have a minimum interlock setting, also
known as the _____. Answer - deadband
Multi-stage thermostats provide energy savings by cycling on stages of heating
or cooling based on _____. Answer - demand
, The thermostat terminal that connects to the reversing valve control in a heat
pump is _____. Answer - O
If a mercury thermostat seems out of adjustment, the first thing to do is _____.
Answer - check for accurate leveling
If a lockout relay becomes defective, it should be replaced with an exact
duplicate, sometimes called a(n) _____. Answer - impedance relay
Electric heat tracing of pipe is done for freeze protection and _____. Answer -
for temperature maintenance of the process fluids
Which of the following is not a factor in determining the appropriate type of
heating cable for a pipe heat-tracing application? Answer - Type of process
fluid
When installing heating cable, fasten the cable to the pipes using fiberglass
tape or _____. Answer - plastic cable ties
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?
Answer - The presence of electric heating equipment must be identified using
permanent caution signs or markings at the specified intervals.
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? Answer - 125%
QUESTIONS AND ANSWERS | 2026 UPDATE | WITH
COMPLETE SOLUTION
Which of the following principles states that heat is created in one place and
carried to another by means of air or water? Answer - Heat-transfer principle
To increase furnace efficiency, the startup of the furnace blower is delayed
using a _____. Answer - time delay relay
A freezestat is a _____. Answer - normally closed bimetal switch
A device that uses dissimilar metals to control electron flow is known as a(n)
_____. Answer - thermocouple
The purpose of the defrost cycle in a heat pump is to _____. Answer - prevent
ice buildup on the outdoor coil
In an air-to-air heat pump, defrost is accomplished by _____. Answer - placing
the unit in the cooling mode
Which of the following is an example of an external analog device? Answer -
Thermistors
,Which of the following occurs as soon as a heating thermostat is closed?
Answer - The inducer fan starts.
Which of these devices can retain a high-voltage charge after power has been
removed? Answer - Capacitors used in motor circuits
NEC Article 440, Part V covers _____. Answer - requirements for motor
compressor controllers
When refrigeration compressors are driven by conventional (nonhermetic)
motors, the motors and controls are subject to the requirements in _____.
Answer - NEC Article 430
The tubing that carries heat-laden refrigerant gas from the evaporator to the
compressor is known as the _____. Answer - suction line
Connecting a 120V heating cable to a 240V circuit will _____. Answer - melt
the cable
A conventional thermostat should not be thrown into the regular trash because
it _____. Answer - may contain mercury
Thermostats with bimetal sensing elements typically use a combination of
copper or brass and _____. Answer - Invar®
Automatic changeover thermostats have a minimum interlock setting, also
known as the _____. Answer - deadband
Multi-stage thermostats provide energy savings by cycling on stages of heating
or cooling based on _____. Answer - demand
, The thermostat terminal that connects to the reversing valve control in a heat
pump is _____. Answer - O
If a mercury thermostat seems out of adjustment, the first thing to do is _____.
Answer - check for accurate leveling
If a lockout relay becomes defective, it should be replaced with an exact
duplicate, sometimes called a(n) _____. Answer - impedance relay
Electric heat tracing of pipe is done for freeze protection and _____. Answer -
for temperature maintenance of the process fluids
Which of the following is not a factor in determining the appropriate type of
heating cable for a pipe heat-tracing application? Answer - Type of process
fluid
When installing heating cable, fasten the cable to the pipes using fiberglass
tape or _____. Answer - plastic cable ties
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?
Answer - The presence of electric heating equipment must be identified using
permanent caution signs or markings at the specified intervals.
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? Answer - 125%
