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Article 400-490 Part02

This quiz consists of 50 carefully selected questions covering NEC Articles 400 through 490, which provide critical guidelines for flexible cords and cables (Article 400), switchgear and control equipment (Article 409), and installations operating above 1000 volts (Article 490). These sections of the National Electrical Code focus on safety, material specifications, and proper installation practices.

The randomly generated questions ensure a thorough assessment of your understanding, reinforcing key principles related to permitted uses of flexible cords, ampacity ratings, industrial control panels, and high-voltage equipment requirements. Some topics may reappear in different contexts to strengthen comprehension and application.

Your feedback is invaluable! If you notice any discrepancies or have suggestions for improvement, please report them. Your insights help maintain the accuracy and effectiveness of this learning tool.

Torque motors are rated differently than standard motors.

1 / 50

How must torque motors be rated for ampacity (430.6(B))?

The protective device must accommodate the high inrush current during motor start.

2 / 50

What is the maximum branch-circuit short-circuit protection for individual motor-compressors (440.22(A))?

Wet locations require specific enclosure protection.

3 / 50

What must be ensured when installing a motor controller in a wet location (430.10(A))?

Liquids can cause motor failure and safety risks.

4 / 50

What protection is required for motors subject to dripping liquids (430.11)?

Clear identification ensures proper use and maintenance.

5 / 50

How must auxiliary devices in motor controllers be marked (430.8(B))?

Outdoor installations require redundancy in grounding.

6 / 50

How must grounding conductors for outdoor air-conditioning equipment be installed (440.9)?

Markings must provide all critical operational data.

7 / 50

What marking is required for controllers used with hermetic refrigerant motor-compressors (440.5)?

Proper connectors ensure safe and durable connections.

8 / 50

What must be provided for the electrical connections of embedded heating elements (426.24)?

Identification ensures visibility and safety throughout the pipeline or vessel.

9 / 50

What is required for identification of electrically heated pipelines and vessels (427.13)?

Sizing must account for continuous operation.

10 / 50

How must branch-circuit conductors for a single motor-compressor be sized (440.32)?

Cord lengths are limited to ensure safety and prevent damage.

11 / 50

What is the allowable cord length for a room air conditioner rated at 120 volts (440.64)?

Disconnecting means ensure safe servicing of heating systems.

12 / 50

What is required for disconnecting means in fixed pipeline or vessel heating systems (427.55(A))?

Manual controllers must ensure accessibility and safety.

13 / 50

What is the requirement for manually operated motor controllers (430.102(A))?

Markings provide essential data for proper application.

14 / 50

What marking is required for motor controllers (430.8)?

Overload protection ensures safety for motor operations.

15 / 50

How must the overload protection for motors on general-purpose branch circuits be configured (430.42)?

Motors require high inrush current at startup.

16 / 50

What is the purpose of time-delay fuses for motor circuits (430.52(C) (1))?

Motor markings provide critical information for installation and operation.

17 / 50

What is required for motor marking (430.7(A))?

The conductor size must account for continuous operation.

18 / 50

What is the ampacity requirement for single motor branch-circuit conductors (430.22)?

NEC defines this type of equipment for specific load calculations.

19 / 50

How is fixed outdoor electric deicing and snow-melting equipment classified (426.4)?

This article addresses motor-driven systems.

20 / 50

What is the scope of Article 440 (440.1)?

NEC specifies reduced starting current for wye-start configurations.

21 / 50

What is the maximum rating for short-circuit protection for wye-start, delta-run motors (430.52)?

Overload protection devices are selected by time rating.

22 / 50

What determines the time rating for overload protection devices (430.32(C))

The largest motor determines the starting point for sizing.

23 / 50

How should conductors for several motors and additional loads be sized (430.24)?

Grounding ensures safety by preventing electrical faults.

24 / 50

What grounding requirement applies to fixed outdoor deicing and snowmelting equipment (426.27)?

Overload protection considers the motor’s service factor.

25 / 50

How must overload devices for continuous-duty motors be rated (430.32)?

Integral thermal protection doesn’t eliminate other requirements.

26 / 50

How must motors with integral thermal protection be installed (430.32(D))?

Capacitor conductors have unique sizing criteria.

27 / 50

How must capacitor conductors for motors be sized (430.83)?

Hazardous locations demand robust construction.

28 / 50

What is required for motor terminal housings in hazardous locations (430.12)?

The NEC specifies precise wire-bending space for safety.

29 / 50

What defines the minimum wire-bending space for motor controller enclosures (430.10(B))?

Emergency stops are critical for motor safety.

30 / 50

What is required for motor emergency stops (430.91)?

Proper grounding is essential for motor control circuits.

31 / 50

How must motor control circuits be grounded (430.72)?

NEC ensures conductors can be safely installed.

32 / 50

How must motor terminal enclosures be sized (430.12(C))?

The watt density ensures effective operation without overheating.

33 / 50

What is the maximum watt density for embedded deicing equipment (426.20(A))?

Serviceability is a key requirement for disconnecting means.

34 / 50

How must disconnecting means for air-conditioning equipment be located (440.14)?

Markings help size circuits and protective devices.

35 / 50

How must equipment supplying multimotor loads be marked (440.4(B))?

All motor windings require proper protection.

36 / 50

How must part-winding motors be protected (430.4)?

Tap conductors must be protected and sized appropriately.

37 / 50

What ampacity must motor feeder tap conductors have when limited to 10 feet in length (430.28(1))?

Article 430 has a broad scope for motor-related systems.

38 / 50

What does NEC Article 430 primarily cover (430.1)?

Grounding conductor sizing is tied to the overcurrent protection.

39 / 50

What is the required size of the equipment grounding conductor for motor circuits (430.122)?

These devices prevent specific electrical hazards in portable units.

40 / 50

What is the requirement for protection devices in cord-connected room air conditioners (440.65)?

Hazardous locations require specific markings for reconditioned equipment.

41 / 50

What must reconditioned motors used in hazardous locations be identified as (430.2)?

NEC specifies protective methods for nonheating leads.

42 / 50

How must nonheating leads for resistance elements be protected where they emerge from heating units (427.18(B))?

The largest motor determines the starting point for feeder sizing.

43 / 50

What is the required ampacity for motor feeder conductors supplying several motors (430.25)?

Protection must account for the combined load of multiple motors.

44 / 50

How must motor branch circuits for two or more motors be protected (430.53)?

High temperatures require measures to prevent accidental contact.

45 / 50

How must external surfaces of heating equipment be protected if operating above 60°C (140°F) (427.12)?

Locked-rotor codes relate to starting current.

46 / 50

What is the purpose of locked rotor indicating code letters on motor nameplates (430.7(B))?

Suitability for the environment ensures durability and safety.

47 / 50

What is required for equipment installed in damp or wet locations (426.10)?

Grounding ensures the motor’s safe operation.

48 / 50

What type of grounding must be provided for motor terminal housings (430.12(E))?

This article focuses on heating systems for industrial applications.

49 / 50

What type of equipment is covered under NEC Article 427 (427.1)?

Nameplates provide essential operational and safety information.

50 / 50

What must the nameplate of a hermetic refrigerant motor-compressor include (440.4(A))?

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