Lesson 4 NEC Chapter 4: Using the Electricity

How many parts exist in Article 410?

16

The maximum distance between two pieces of electrical equipment that are considered to be in sight of each other is ? . a. 50' b. 75' c. 100' d. none of the above

50', 100

The ampacity of 18 AWG fixture wire is ? . a. 2 A b. 4 A c. 6 A d. 12 A

6 A, 402.5

Industrial control-panel enclosures shall not be used as junction boxes, auxiliary gutters, or raceways for conductors feeding through or tapping off to other switches or overcurrent devices or other equipment, unless the conductors fill less than 50% of the cross-sectional area of the wiring space. a. True b. False

F, 409.104(A)

Under no condition is the attachment plug cap for a 240-volt room air conditioner in a residential occupancy permitted to be used as the disconnecting means for the room air conditioner. a. True b. False

F, 440.63

Each autotransformer 1,000 volts, nominal, or less shall be protected by an individual overcurrent device installed with each ungrounded input conductor and installed in series with the winding common to both the primary and secondary (shunt winding) of an autotransformer. a. True b. False

F, 450.4(A)

Insulated conductors used within a switchboard or switchgear shall be listed, flame retardant, and voltage rated. a. True b. False

T, 408.19

A panelboard containing a 4-wire, delta-connected system shall be permanently field marked to identify the voltage to ground on the high leg. a. True b. False

T, 408.3(F)(1)

In a residential occupancy, two fixed electric space-heating units are permitted to be supplied by a 30-ampere branch circuit. a. True b. False

T, 424.4(A)

When pipelines are electrically heated, the pipelines must be identified by caution signs or markings. a. True b. False

T, 427.13

A luminaire measuring 12 inches in diameter and weighing six pounds is supported by a screwshell of a lampholder. a. Acceptable b. Violation

acceptable, 410.30(A)

Type SJ flexible cord is recognized ? . a. as a hard usage cord b. as an extra-hard usage cord c. as not a hard usage cord d. for use in dry locations only

as a hard usage cord, 400.4

High-voltage is defined as a potential difference of more than ? , nominal. a. 600 V b. 1,000 V c. 2,000 V d. 4,160 V

b. 1,000 V, 490.2

Low-voltage lighting systems shall not be supplied by a branch circuit rated greater than ? . a. 15 A b. 20 A c. 25 A d. 30 A

b. 20 A, 411.7

The voltage of a storage battery having 12 lead-acid type cells connected in series will be ? . a. 12 V b. 24 V c. 48 V d. 144 V

b. 24 V

The full-load current of a 25-horsepower, 480-volt, 3-phase, squirrel-cage induction motor is ? . a. 27 A b. 34 A c. 68 A d. 74.8 A

b. 34 A, Table 430.250

Which of the following locations would not require a 15-ampere, 125-volt nonlocking-type receptacle to be listed tamper resistant? a. Classroom of a preschool b. Conference room of a business office c. Common area of a hotel d. Dining rooms of a dwelling unit

b. Conference room of a business office, 406.12

A cord-and-plug-connected kitchen waste disposer is installed below the kitchen sink, with the receptacle accessible. A four-foot length of Type SJ cord not subject to physical damage is used. a. Acceptable b. Violation

b. Violation, 422.16(B)(1)(1)

Which of the following conditions must be met before two or more 120-volt, one-horsepower or less motors are permitted to be installed on the same 20-ampere branch circuit? a. The full-load current rating of each motor does not exceed 6 A. b. The rating of the branch-circuit short-circuit and ground-fault protective device marked on any of the controllers is not exceeded. c. Both a. and b. d. Neither a. nor b.

both a and b 430.53(A)

An embedded deicing unit of the resistance type shall not exceed ? of heated area. a. 50 watts/ft^2 b. 100 watts/ft^2 c. 120 watts/ft^2 d. 200 watts/ft^2

c. 120 watts/ft^2, 426.20(A)

When a capacitor that operates at 1,000 volts or less is removed from an energized circuit, the charge on the capacitor shall be drained to ? or less within ? .

c. 50 V / 1 minute 460.6(A)

A panelboard is designed to be placed in a ? .

cabinet, 100

The means of emergency shutdown used for a generator's prime mover shall comply with which of the following provisions? a. Be lockable closed in accordance with NEC 110.25 b. Be equipped with provisions to disable all prime mover start control circuits to render the prime mover incapable of starting c. Initiate a shutdown mechanism that requires a mechanical reset d. Both b. and c.

d. Both b. and c., 445.18(B)

Fixed, industrial-process heating equipment and motors shall be considered ? . a. enclosed b. watertight c. continuous duty d. continuous loads

d. continuous loads, 425.4(B)

A single-throw knife switch shall not be installed in a manner that will ? . a. have the switch in a horizontal position b. require a locking device c. require hand operation d. tend to close the switch with gravity

d. tend to close the switch with gravity 404.6(A)

What type(s) of phase converters are covered by the NEC? a. Reversible b. Rotary c. Static d. Both a. and b. e. Both b. and c.

e. Both b. and c., 455.2

? duty is defined as intermittent operation in which the load conditions are regularly recurrent. a. Continuous b. Intermittent c. Periodic d. Varying

periodic, 100

An overhead projector is mounted below a suspended ceiling of a classroom. The power supply cord serving the projector is run through a hole in the suspended ceiling and is plugged into a receptacle outlet above the ceiling. a. Acceptable b. Violation

violation, 400.12(2)

Three-way switches are installed with the grounded conductor being switched in order to control a lighting fixture from two locations. a. Acceptable b. Violation

violation, 404.2(A)

A 100-ampere resistor bank is connected to a controller with conductor insulation rated 75°C. The resistors are not used in conjunction with the starting current of a motor. a. Acceptable b. Violation

violation, 470.4