Question 1

Class 2 circuits are ____________________ and are considered safe from fire hazard and from electric shock hazard

Accepted Answer

"power-limited"
"power limited"
power limited
power-limited

Question 2

In the diagram below, label the type of circuit represented by each part of the installation, choosing from among the following. You may or may not require all the types listed.  Power supply wiring
Class 1 wiring
Class 2 wiring
Class 3 wiring
Communications wiring

Accepted Answer

A = Class 2 wiring
B = Power supply wiring
C = Class 1 wiring

Question 3

How does the Code define a remote-control circuit?

Accepted Answer

A remote-control circuit is any circuit that controls another circuit through a relay or equivalent device.

Question 4

Residential thermostats should be located where they will not be influenced by ____.

Accepted Answer

Residential thermostats should not be influenced by drafts, radiated heat, or direct sunlight in order to accurately control the temperature of the room. Therefore, it is best to avoid all of the above factors and locate the thermostat in a neutral, central location.

Question 5

Do not throw selenium thermostats into the trash because the selenium is considered hazardous waste material.

Accepted Answer

Selenium thermostats are not considered hazardous waste material; it's mercury thermostats that are considered hazardous due to the mercury content, not selenium. Selenium is used in some electronic components for its semiconductor properties, but the concern over hazardous waste typically involves mercury in thermostats.

Question 6

Disconnect switches for furnaces installed in basements are required to be ____.

Accepted Answer

Disconnect switches for furnaces must be installed within sight of the appliance to ensure safety and compliance with electrical codes.

Question 7

Which of the following is NOT a typical Class 2 wiring application in homes?

Accepted Answer

Low-voltage lighting typically involves Class 2 wiring, making it a typical application in homes. Therefore, D is the answer as it is NOT a typical application. A, B, and C are all typical applications for Class 2 wiring in homes.

Question 8

Explain the purpose of interrupted duty ignition on a gas furnace.

Accepted Answer

The answer of Explain the purpose of interrupted duty ignition...

Question 9

Low-voltage wiring used for door bell and thermostat wiring in a residence is generally Class 2 wiring, which has a thermoplastic insulation with a voltage rating of not less than ____________________ volts.

Accepted Answer

The answer of Low-voltage wiring used for door bell and...

Question 10

NEC 422.12 requires that central heating equipment of any type (electric resistance, gas, oil, heat pump) must ____.

Accepted Answer

NEC 422.12 requires that central heating equipment must be supplied by an individual branch circuit to ensure safety and proper operation.

Question 11

Because they have internal overload protection, listed Class 2 transformers are permitted to be supplied by branch circuits having overcurrent protection not exceeding ____ amperes.

Accepted Answer

Listed Class 2 transformers are permitted to be supplied by branch circuits having overcurrent protection not exceeding 20 amperes.

Question 12

Thermostats are usually mounted approximately ____ in. above the finished floor.

Accepted Answer

The answer of Thermostats are usually mounted approximately ____ in....

Question 13

Most residential heating systems are packaged units in which many items are preassembled, prewired parts of the furnace or boiler. They are included in an integrated printed circuit board module, which is the "____" of the system.

Accepted Answer

The integrated printed circuit board module is the brain of the system, controlling and coordinating all the functions of the furnace or boiler. The other choices (core, guts, heart) do not accurately describe the function of the circuit board.

Question 14

Class 2 wiring ____ permitted in the same raceway, cable, compartment, outlet box, or fitting with light and power conductors, even if the Class 2 conductors have the same 600-volt insulation as the power conductors.

Accepted Answer

Class 2 wiring is not permitted in the same raceway, cable, compartment, outlet box or fitting with light and power conductors, even if the Class 2 conductors have the same 600-volt insulation as the power conductors. This is to prevent any potential electrical hazards and to ensure proper functioning of both types of wiring.

Question 15

Oil-fired heating systems move hot air from the furnace through hot air ducts that in turn connect to hot air registers strategically located throughout the home.

Accepted Answer

The answer of Oil-fired heating systems move hot air from...

Question 16

____ circuits offer alternative wiring methods regarding voltage, power limitations, wire size, derating factors, overcurrent protection, physical protection, insulation, and materials that differentiate these types of circuits from conventional wiring methods.

Accepted Answer

Class 1, Class 2, and Class 3 circuits offer a wide range of options for wiring methods that differ from conventional wiring methods. These options include variations in voltage, power limitations, wire size, derating factors, overcurrent protection, physical protection, insulation, and materials used.

Question 17

Hot water systems are very adaptable to zone control by using a combination of one or more circulating pumps and/or valves for the different zones. Hot water heating systems are referred to as ____________________ systems.

Accepted Answer

The answer of Hot water systems are very adaptable to...

Question 18

A remote-control circuit is any electrical circuit that ____________________ through a relay or equivalent device.

Accepted Answer

The answer of A remote-control circuit is any electrical circuit...

Question 19

Class 2 power source voltage limitations, current limitations, and overcurrent protection requirements are found in ____.

Accepted Answer

The answer of Class 2 power source voltage limitations, current...

Question 20

Manufacturers of heating and cooling equipment provide separate openings for bringing in the Class 2 wiring and separate openings for bringing in the power supply.

Accepted Answer

This is true because the Class 2 wiring is low voltage wiring, often used for control systems, while the power supply is high voltage wiring. It is important to keep these two types of wiring separate for safety reasons.

Quiz 24: Gas and Oil Central Heating Systems