Deck 23: Special-Purpose Outletselectric Heating, Air Conditioning

Question 1

For ease of identification, NEC 424.35 requires that leads on heating cables be color-coded. Match the voltages below with the required colors.
a.red
b.blue
c.orange
d.yellow
e.brown
120 volts

Answer 1

d

Question 2

Explain the reason that baseboard heating manufacturers do not permit their baseboard heaters to be installed below wall receptacle outlets.

Answer 2

A possible fire and shock hazard could result if the insulation were to melt on an appliance cord hanging down and touching the hot baseboard unit.

Question 3

When Class 2 control wiring is used with central heating and air-conditioning equipment, what is the Code section that prohibits running Class 2 wiring in the same raceway as power conductors?

Answer 3

NEC 725.136(A)

Question 4

The total load of an air conditioner shall not exceed ____ percent of the rating of a branch circuit that also supplies lighting.

A) 50
B) 75
C) 80
D) 125

Question 5

When making a calculation for sizing a service or feeder, you must include 125 percent of the rating of the total connected fixed space heating load.

Question 6

The total load of an air conditioner shall not exceed ____ percent of the rating of a separate branch circuit.

A) 50
B) 75
C) 80
D) 125

Question 7

Explain how NEC 422.11 affects selection of branch circuit conductors for appliances, including electric furnaces.

Question 8

The article that covers cord-and-plug connected air conditioners is ____.

A) Article 210
B) Article 422
C) Article 430
D) Article 440

Question 9

The disconnect for motor-driven appliances having a motor of greater than ____ must be within sight of the appliance.

A) 1/8 hp
B) 1/4 hp
C) 1/2 hp
D) 3/4 hp

Question 10

Explain what the NEC requires for a white wire used as an ungrounded (hot) conductor.

Question 11

The disconnecting means and branch circuit conductors for an electric furnace shall be sized not less than ____ percent of the total nameplate load shown on the furnace.

A) 125
B) 150
C) 225
D) none of these

Question 12

NEC 422.12 on central heating equipment requires that ____.

A) electric furnace overcurrent protection be provided by fuses only
B) central heating equipment be provided by a separate branch circuit
C) electric furnaces be grounded according to the requirements of Article 250
D) a disconnecting means be provided for central heating equipment

Question 13

The NEC permits flexible cords to be used to supply appliances where ____.

A) the appliance is designed to permit ready removal for maintenance and repair
B) the appliance weighs less than 100 pounds
C) the appliance is identified for flexible cord connection
D) both a and c

Question 14

Although two-wire cables, such as Type NM and Type AC, contain one black and one white insulated conductor, they are frequently used in residential wiring to supply 240-volt loads. Explain how this can be permitted.

Question 15

Baseboard heating units can be controlled by ____.

A) line-voltage thermostats
B) low-voltage thermostats
C) on-off switches
D) both a and b

Question 16

The air-conditioner load shall not exceed ____________________ percent of the branch-circuit ampacity if other loads are also served.

Question 17

A receptacle is not required for one and two-family homes if the HVAC equipment is a(n) ____________________. These require minimal servicing.

Question 18

Where a flexible cord is used to supply a room air conditioner, the length of the flexible cord shall not exceed ____ for 120-volt units.

A) 6 ft (1.8 m)
B) 8.0 ft (2.4 m)
C) 10 ft (3.0 m)
D) 12 ft (3.6 m)

Question 19

The maximum current and voltage rating permitted by Code for a cord-and-plug connected air-conditioner is ______________________________ at 250 volts.

Question 20

List at least three advantages of electric heating as compared to other types of residential heating systems.

Question 21

For ease of identification, NEC 424.35 requires that leads on heating cables be color-coded. Match the voltages below with the required colors.
a.red
b.blue
c.orange
d.yellow
e.brown
208 volts

Question 22

For ease of identification, NEC 424.35 requires that leads on heating cables be color-coded. Match the voltages below with the required colors.
a.red
b.blue
c.orange
d.yellow
e.brown
480 volts

Question 23

Match the following abbreviations used for current values associated with HVAC (heating, ventilating, and air-conditioning) equipment with their meanings.
a.Minimum requirement to determine the conductor size and switch rating
b.Value used to select branch circuit conductors and disconnect
c.Maximum current a motor compressor can draw before damage occurs
MOP

Question 24

Match the following abbreviations used for current values associated with HVAC (heating, ventilating, and air-conditioning) equipment with their meanings.
a.Minimum requirement to determine the conductor size and switch rating
b.Value used to select branch circuit conductors and disconnect
c.Maximum current a motor compressor can draw before damage occurs
BCSC

Question 25

For ease of identification, NEC 424.35 requires that leads on heating cables be color-coded. Match the voltages below with the required colors.
a.red
b.blue
c.orange
d.yellow
e.brown
240 volts

Question 26

Match the following abbreviations used for current values associated with HVAC (heating, ventilating, and air-conditioning) equipment with their meanings.
a.Minimum requirement to determine the conductor size and switch rating
b.Value used to select branch circuit conductors and disconnect
c.Maximum current a motor compressor can draw before damage occurs
MCA

Question 27

For ease of identification, NEC 424.35 requires that leads on heating cables be color-coded. Match the voltages below with the required colors.
a.red
b.blue
c.orange
d.yellow
e.brown
277 volts