, Solution manual for Illustrated Guide to the
National Electrical Code, 9th Edition Charles R.
Miller
Notes
1- The file is chapter after chapter.
2- We have shown you 10 or five pages.
3- The file contains all Appendix and Excel
sheet if it exists.
4- We have all what you need, we make
update at every time. There are many new
editions waiting you.
5- If you think you purchased the wrong file
You can contact us at every time, we can
replace it with true one.
Our email:
,Solution and Answer Guide: Miller/Sandefur, Illustrated Guide to the NEC®, ©2024, 9780357766712, Unit 1: Introduction to the National Electrical Code®
Solution and Answer Guide
MILLER/S ANDEFUR, ILLUSTRATED GUIDE TO THE NEC®, 21E, ©2024, 9780357766712; UNIT 1:
INTRODUCTION TO THE NATIONAL E LECTRICAL CODE®
TABLE OF CONTENTS
Unit 1 Competency Test ............................................................................................................................. 1
UNIT 1 COMPETENCY TEST
1. The National Fire Protection Association has acted as sponsor of the National Electrical
Code since__________________.
a. NEC® Reference: Page 1
b. Answer: 1911
2. Informative Annex _______________ provides a list of product safety standards used for
product listing where that listing is required by the NEC.
a. NEC® Reference: Informative Annex A
b. Answer: A
3. Which chapters in the NEC apply generally to all installations?
a. NEC® Reference: 90.3
b. Answer: Chapters 1, 2, 3, and 4
4. Every three years, the National Electrical Code is revised, but the Code has only been on a
three-year revision cycle since _______________.
a. NEC® Reference: Page 1
b. Answer: 1975
5. The purpose of the National Electrical Code is the practical safeguarding of ___________
from hazards arising from the use of electricity.
a. NEC® Reference: persons and property
b. Answer: 90.2(A)
6. The original Code document was developed _______________ in as a result of the united
efforts of various insurance, electrical, architectural, and allied interests.
a. NEC® Reference: Page 1
b. Answer: 1897
© 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible 1
website, in whole or in part.
,Solution and Answer Guide: Miller/Sandefur, Illustrated Guide to the NEC®, ©2024, 9780357766712, Unit 1: Introduction to the National Electrical Code®
7. Informative annexes are not part of the requirements of the NEC but are included for
_______________ only.
a. NEC® Reference: 90.3
b. Answer: informational purposes
8. What city was home to the first central-station electric generating plant developed by
Thomas A. Edison?
a. NEC® Reference: Page 2
b. Answer: New York City
9. Chapter _______________ consists of tables that are applicable as referenced.
a. NEC® Reference: 90.3
b. Answer: 9
10. In the NEC, UL is the abbreviation for _______________.
a. NEC® Reference: Annex I, footnote under Table I.3
b. Answer: Underwriters Laboratories
11. Equipment that is listed, labeled, or both, or identified for a use shall be installed and
used in accordance with any _______________ included in the listing, labeling, or
identification.
a. NEC® Reference: 110.3(B)
b. Answer: instructions
© 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible 2
website, in whole or in part.
, Solution and Answer Guide: Miller/Sandefur, Illustrated Guide to the NEC®, ©2024, 9780357766712, Unit 2: Definitions®
Solution and Answer Guide
MILLER/S ANDEFUR, ILLUSTRATED GUIDE TO THE NEC®, 21E, ©2024, 9780357766712;
UNIT 2: DEFINITIONS®
TABLE OF CONTENTS
Unit 2 Competency Test ............................................................................................................................. 1
UNIT 2 COMPETENCY TEST
1. A(n) __________________ branch circuit supplies two or more receptacles or outlets for
lighting and appliances.
a. NEC® Reference: Article 100 (Branch-Circuit, General Purpose)
b. Answer: general purpose
2. __________________ is the largest amount of current capable of being delivered at a
point on the electrical system during a short-circuit condition.
a. NEC® Reference: Article 100 (Fault Current, Available)
b. Answer: Available fault current
3. A(n) __________________ branch circuit consists of two or more ungrounded conductors
having a potential difference between them, and a grounded conductor having equal
potential difference between it and each ungrounded conductor of the circuit and that is
connected to the neutral or grounded conductor of the system.
a. NEC® Reference: multiwire
b. Answer: Article 100 (Branch-Circuit, Multiwire)
4. An intermittent operation in which load conditions are regularly recurrent is the definition
of __________________.
a. NEC® Reference: Article 100 (Duty, Periodic)
b. Answer: periodic duty
5. The __________________ is the connection between the grounded-circuit conductor and
the equipment grounding conductor at the service.
a. NEC® Reference: Article 100 (Bonding Jumper, Main)
b. Answer: main bonding jumper
© 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible 1
website, in whole or in part.
, Solution and Answer Guide: Miller/Sandefur, Illustrated Guide to the NEC®, ©2024, 9780357766712, Unit 2: Definitions®
6. A(n) __________________ is used to connect the system grounded conductor or the
equipment to a grounding electrode or to a point on the grounding electrode system.
a. NEC® Reference: Article 100 (Grounding Electrode Conductor)
b. Answer: grounding electrode conductor
7. Rainproof, raintight, or watertight equipment can fulfill the requirements for
__________________ where varying weather conditions other than wetness, such as
snow, ice, dust, or temperature extremes, are not a factor.
a. NEC® Reference: Article 100 (Weatherproof: Informational Note)
b. Answer: weatherproof
8. A(n) __________________ is an intentionally constructed, low-impedance electrically
conductive path designed and intended to carry current during ground-fault events from
the point of a ground fault on a wiring system to the electrical supply source and that
facilitates the operation of the overcurrent protective device or ground-fault detectors.
a. NEC® Reference: Article 100 (Ground Fault Current Path, Effective)
b. Answer: effective ground-fault current path
9. A(n) __________________ is a manual, nonautomatic, or automatic operated device used
in conjunction with a transfer switch to provide a means of directly connecting load
conductors to a power source and of disconnecting the transfer switch.
a. NEC® Reference: Article 100 (Transfer Switch, Bypass Isolation)
b. Answer: bypass isolation transfer switch
10. A surface, flush, or freestanding assemblage with a raceway, fittings, or other enclosure
provided with one or more receptacles, for the purpose of supplying power to utilization
equipment is called a(n).
a. NEC® Reference: Article 100 (Multioutlet Assembly)
b. Answer: multioutlet assembly
11. A raceway encased in 4 in. (102 mm) of concrete on the ground floor (in direct contact with
the earth) shall be considered a(n) __________________ location.
a. NEC® Reference: Article 100 (Location, Wet)
b. Answer: wet
12. A(n) __________________ may consist of one or more sensing elements integral with the
motor-compressor and an external control device.
a. NEC® Reference: Article 100 (Thermal Protector: Informational Note)
b. Answer: thermal protector
© 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible 2
website, in whole or in part.
, Solution and Answer Guide: Miller/Sandefur, Illustrated Guide to the NEC®, ©2024, 9780357766712, Unit 2: Definitions®
13. An enclosure designed for either surface or flush mounting and provided with a frame,
mat, or trim in which a swinging door or doors are or can be hung is called a(n)
__________________.
a. NEC® Reference: Article 100 (Cabinet)
b. Answer: cabinet
14. A(n) __________________ is a shaftway, hatchway, well hole, or other vertical opening of
space in which an elevator or dumbwaiter is designed to operate.
a. NEC® Reference: Article 100 (Hoistway)
b. Answer: hoistway
15. A multiwire branch circuit can supply:
I. 20/240 volts to only one piece of utilization equipment
II. 120/240 volts where all ungrounded conductors are opened simultaneously
a) I only b) II only c) both I and II d) neither I nor II
a. NEC® Reference: 210.4(C) Exceptions No. 1 and 2
b. Answer: c) both I and II
16. An overcurrent protective device with a circuit opening fusible part that is heated and
severed by the passage of overcurrent through it is the definition of a(n)
__________________.
a. NEC® Reference: Article 100 (Fuse)
b. Answer: fuse
17. __________________ is a string of outdoor lights suspended between two points.
a. NEC® Reference: Article 100 (Festoon Lighting)
b. Answer: Festoon lighting
18. Name two items that must be present when defining an area as a bathroom.
a. NEC® Reference: Article 100 (Bathroom)
b. Answer: One item named must be a sink; the other item can be a toilet, a urinal, a
tub, a shower, a bidet, or similar plumbing fixture.
19. A continuous load is where the __________________ current is expected to continue for
three hours or more.
a) 80% b) average c) maximum d) 125%
a. NEC® Reference: Article 100 (Continuous Load)
b. Answer: c) maximum
20. Solidly grounded is defined as connected to ground without inserting any
__________________ or impedance device.
a. NEC® Reference: Article 100 (Grounded, Solidly)
b. Answer: resistor
© 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible 3
website, in whole or in part.
, Solution and Answer Guide: Miller/Sandefur, Illustrated Guide to the NEC®, ©2024, 9780357766712, Unit 2: Definitions®
21. A(n) __________________ is a point on the wiring system at which current is taken to
supply utilization equipment.
a. NEC® Reference: Article 100 (Outlet)
b. Answer: outlet
22. A(n) __________________ is defined as the circuit conductors between the final
overcurrent device protecting the circuit and the outlet(s).
a. NEC® Reference: Article 100 (Branch-Circuit)
b. Answer: branch-circuit
23. __________________ enclosures are constructed or protected so that exposure to a
beating rain will not result in the entrance of water under specified test conditions.
a. NEC® Reference: Article 100 (Raintight)
b. Answer: Raintight
24. Continuous duty is an operation at a substantially constant load for __________________.
a) 1 hour or more b) 1½ hours or more
c) 3 hours or more d) an indefinitely long time
a. NEC® Reference: Article 100 (Duty, Continuous)
b. Answer: d) an indefinitely long time
25. Ampacity is defined as the maximum current, in amperes, that a conductor can carry
continuously under the conditions of use without exceeding __________________.
a. NEC® Reference: Article 100 (Ampacity)
b. Answer: its temperature rating
26. When a disconnecting means must be located within sight from a motor, the disconnect
must be visible and not more than __________________ ft from the motor.
a. NEC® Reference: Article 100 (In Sight From [Within Sight From, Within Sight])
b. Answer: 50
27. A building containing three dwelling units is called a(n) __________________.
a. NEC® Reference: Article 100 (Dwelling, Multifamily)
b. Answer: multifamily dwelling
28. Ground is defined as __________________.
a. NEC® Reference: Article 100 (Ground)
b. Answer: the earth
© 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible 4
website, in whole or in part.
, Solution and Answer Guide: Miller/Sandefur, Illustrated Guide to the NEC®, ©2024, 9780357766712, Unit 2: Definitions®
29. At the neutral point of the system, the __________________ of the nominal voltages from
all other phases within the system that utilize the neutral, with respect to the neutral point,
is zero potential.
a. NEC® Reference: Article 100 (Neutral Point: Informational Note)
b. Answer: vectorial sum
30. Four panelboards are in an electrical room behind locked doors. Only authorized personnel
have keys to this electrical room. In accordance with 240.24, overcurrent devices shall be
readily accessible. Since a key must be used to gain entry into the electrical room, are the
overcurrent devices in these panelboards considered readily accessible?
a. NEC® Reference: Article 100 (Accessible, Readily)
b. Answer: yes
31. A(n) __________________ is defined as an electrical power supply output, other than a
service, having no direct connection(s) to circuit conductors of any other electrical source
other than those established by grounding and bonding connections.
a. NEC® Reference: Article 100 (Separately Derived System)
b. Answer: separately derived system
32. A feeder is defined as all circuit conductors between the service equipment, the source of a
separately derived system, or other power supply source and the final __________________
overcurrent device.
a. NEC® Reference: Article 100 (Feeder)
b. Answer: branch-circuit
33. A(n) __________________ is defined as utilization equipment, generally other than
industrial, that is fastened in place, stationary, or portable; is normally built in a
standardized size or type; and is installed or connected as a unit to perform one or more
functions such as clothes washing, air-conditioning, food mixing, deep frying, and so forth.
a. NEC® Reference: Article 100 (Appliance)
b. Answer: appliance
34. A motor branch circuit includes the circuit conductors as well as the equipment between
the motor branch-circuit short-circuit and ground-fault protective device and a(n)
__________________ motor.
a. NEC® Reference: Article 100 (Branch Circuit, Motor)
b. Answer: individual
© 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible 5
website, in whole or in part.
, Solution and Answer Guide: Miller/Sandefur, Illustrated Guide to the NEC®, ©2024, 9780357766712, Unit 3: Boxes and Enclosures®
Solution and Answer Guide
MILLER/S ANDEFUR, ILLUSTRATED GUIDE TO THE NEC®, 21E, ©2024, 9780357766712; UNIT 3:
INTRODUCTION TO THE NATIONAL E LECTRICAL CODE®
TABLE OF CONTENTS
Unit 3 Competency Test ............................................................................................................................. 1
UNIT 3 COMPETENCY TEST
1. In pull boxes or junction boxes having any dimension over __________________ in., all
conductors shall be cabled or racked up in an approved manner.
a) 6 b) 12 c) 36 d) 72
a. NEC® Reference: 314.28(B)
b. Answer: d) 72; 6 (ft) x 12 (in.) = 72 in.
2. Boxes and conduit bodies in buildings shall be installed so the contained wiring and devices are
__________________.
a. NEC® Reference: 314.29(A)
b. Answer: accessible
3. What are the minimum dimensions for “X” and “Y” in the drawing below if the conductors
within the 3-in. conduit are pulled straight through the 3-in. conduit on the opposite wall and
the conductors in the 2-in. conduit are pulled through the 2-in. conduit on the adjacent wall?
All conductors are 4 AWG and larger.
a. NEC® Reference: 314.28(A)
b. Answer: “X” = 24 in., and “Y” = 12 in. The “X” dimension contains both straight and
angle pulls. Use the larger of the two. “X” (straight pull) = 3 x 8 = 24. “X” (angle pull)
3 x 6 + 2 = 20. The “Y” dimension has an angle pull only. “Y” = 2 x 6 = 12.
© 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible 1
website, in whole or in part.
National Electrical Code, 9th Edition Charles R.
Miller
Notes
1- The file is chapter after chapter.
2- We have shown you 10 or five pages.
3- The file contains all Appendix and Excel
sheet if it exists.
4- We have all what you need, we make
update at every time. There are many new
editions waiting you.
5- If you think you purchased the wrong file
You can contact us at every time, we can
replace it with true one.
Our email:
,Solution and Answer Guide: Miller/Sandefur, Illustrated Guide to the NEC®, ©2024, 9780357766712, Unit 1: Introduction to the National Electrical Code®
Solution and Answer Guide
MILLER/S ANDEFUR, ILLUSTRATED GUIDE TO THE NEC®, 21E, ©2024, 9780357766712; UNIT 1:
INTRODUCTION TO THE NATIONAL E LECTRICAL CODE®
TABLE OF CONTENTS
Unit 1 Competency Test ............................................................................................................................. 1
UNIT 1 COMPETENCY TEST
1. The National Fire Protection Association has acted as sponsor of the National Electrical
Code since__________________.
a. NEC® Reference: Page 1
b. Answer: 1911
2. Informative Annex _______________ provides a list of product safety standards used for
product listing where that listing is required by the NEC.
a. NEC® Reference: Informative Annex A
b. Answer: A
3. Which chapters in the NEC apply generally to all installations?
a. NEC® Reference: 90.3
b. Answer: Chapters 1, 2, 3, and 4
4. Every three years, the National Electrical Code is revised, but the Code has only been on a
three-year revision cycle since _______________.
a. NEC® Reference: Page 1
b. Answer: 1975
5. The purpose of the National Electrical Code is the practical safeguarding of ___________
from hazards arising from the use of electricity.
a. NEC® Reference: persons and property
b. Answer: 90.2(A)
6. The original Code document was developed _______________ in as a result of the united
efforts of various insurance, electrical, architectural, and allied interests.
a. NEC® Reference: Page 1
b. Answer: 1897
© 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible 1
website, in whole or in part.
,Solution and Answer Guide: Miller/Sandefur, Illustrated Guide to the NEC®, ©2024, 9780357766712, Unit 1: Introduction to the National Electrical Code®
7. Informative annexes are not part of the requirements of the NEC but are included for
_______________ only.
a. NEC® Reference: 90.3
b. Answer: informational purposes
8. What city was home to the first central-station electric generating plant developed by
Thomas A. Edison?
a. NEC® Reference: Page 2
b. Answer: New York City
9. Chapter _______________ consists of tables that are applicable as referenced.
a. NEC® Reference: 90.3
b. Answer: 9
10. In the NEC, UL is the abbreviation for _______________.
a. NEC® Reference: Annex I, footnote under Table I.3
b. Answer: Underwriters Laboratories
11. Equipment that is listed, labeled, or both, or identified for a use shall be installed and
used in accordance with any _______________ included in the listing, labeling, or
identification.
a. NEC® Reference: 110.3(B)
b. Answer: instructions
© 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible 2
website, in whole or in part.
, Solution and Answer Guide: Miller/Sandefur, Illustrated Guide to the NEC®, ©2024, 9780357766712, Unit 2: Definitions®
Solution and Answer Guide
MILLER/S ANDEFUR, ILLUSTRATED GUIDE TO THE NEC®, 21E, ©2024, 9780357766712;
UNIT 2: DEFINITIONS®
TABLE OF CONTENTS
Unit 2 Competency Test ............................................................................................................................. 1
UNIT 2 COMPETENCY TEST
1. A(n) __________________ branch circuit supplies two or more receptacles or outlets for
lighting and appliances.
a. NEC® Reference: Article 100 (Branch-Circuit, General Purpose)
b. Answer: general purpose
2. __________________ is the largest amount of current capable of being delivered at a
point on the electrical system during a short-circuit condition.
a. NEC® Reference: Article 100 (Fault Current, Available)
b. Answer: Available fault current
3. A(n) __________________ branch circuit consists of two or more ungrounded conductors
having a potential difference between them, and a grounded conductor having equal
potential difference between it and each ungrounded conductor of the circuit and that is
connected to the neutral or grounded conductor of the system.
a. NEC® Reference: multiwire
b. Answer: Article 100 (Branch-Circuit, Multiwire)
4. An intermittent operation in which load conditions are regularly recurrent is the definition
of __________________.
a. NEC® Reference: Article 100 (Duty, Periodic)
b. Answer: periodic duty
5. The __________________ is the connection between the grounded-circuit conductor and
the equipment grounding conductor at the service.
a. NEC® Reference: Article 100 (Bonding Jumper, Main)
b. Answer: main bonding jumper
© 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible 1
website, in whole or in part.
, Solution and Answer Guide: Miller/Sandefur, Illustrated Guide to the NEC®, ©2024, 9780357766712, Unit 2: Definitions®
6. A(n) __________________ is used to connect the system grounded conductor or the
equipment to a grounding electrode or to a point on the grounding electrode system.
a. NEC® Reference: Article 100 (Grounding Electrode Conductor)
b. Answer: grounding electrode conductor
7. Rainproof, raintight, or watertight equipment can fulfill the requirements for
__________________ where varying weather conditions other than wetness, such as
snow, ice, dust, or temperature extremes, are not a factor.
a. NEC® Reference: Article 100 (Weatherproof: Informational Note)
b. Answer: weatherproof
8. A(n) __________________ is an intentionally constructed, low-impedance electrically
conductive path designed and intended to carry current during ground-fault events from
the point of a ground fault on a wiring system to the electrical supply source and that
facilitates the operation of the overcurrent protective device or ground-fault detectors.
a. NEC® Reference: Article 100 (Ground Fault Current Path, Effective)
b. Answer: effective ground-fault current path
9. A(n) __________________ is a manual, nonautomatic, or automatic operated device used
in conjunction with a transfer switch to provide a means of directly connecting load
conductors to a power source and of disconnecting the transfer switch.
a. NEC® Reference: Article 100 (Transfer Switch, Bypass Isolation)
b. Answer: bypass isolation transfer switch
10. A surface, flush, or freestanding assemblage with a raceway, fittings, or other enclosure
provided with one or more receptacles, for the purpose of supplying power to utilization
equipment is called a(n).
a. NEC® Reference: Article 100 (Multioutlet Assembly)
b. Answer: multioutlet assembly
11. A raceway encased in 4 in. (102 mm) of concrete on the ground floor (in direct contact with
the earth) shall be considered a(n) __________________ location.
a. NEC® Reference: Article 100 (Location, Wet)
b. Answer: wet
12. A(n) __________________ may consist of one or more sensing elements integral with the
motor-compressor and an external control device.
a. NEC® Reference: Article 100 (Thermal Protector: Informational Note)
b. Answer: thermal protector
© 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible 2
website, in whole or in part.
, Solution and Answer Guide: Miller/Sandefur, Illustrated Guide to the NEC®, ©2024, 9780357766712, Unit 2: Definitions®
13. An enclosure designed for either surface or flush mounting and provided with a frame,
mat, or trim in which a swinging door or doors are or can be hung is called a(n)
__________________.
a. NEC® Reference: Article 100 (Cabinet)
b. Answer: cabinet
14. A(n) __________________ is a shaftway, hatchway, well hole, or other vertical opening of
space in which an elevator or dumbwaiter is designed to operate.
a. NEC® Reference: Article 100 (Hoistway)
b. Answer: hoistway
15. A multiwire branch circuit can supply:
I. 20/240 volts to only one piece of utilization equipment
II. 120/240 volts where all ungrounded conductors are opened simultaneously
a) I only b) II only c) both I and II d) neither I nor II
a. NEC® Reference: 210.4(C) Exceptions No. 1 and 2
b. Answer: c) both I and II
16. An overcurrent protective device with a circuit opening fusible part that is heated and
severed by the passage of overcurrent through it is the definition of a(n)
__________________.
a. NEC® Reference: Article 100 (Fuse)
b. Answer: fuse
17. __________________ is a string of outdoor lights suspended between two points.
a. NEC® Reference: Article 100 (Festoon Lighting)
b. Answer: Festoon lighting
18. Name two items that must be present when defining an area as a bathroom.
a. NEC® Reference: Article 100 (Bathroom)
b. Answer: One item named must be a sink; the other item can be a toilet, a urinal, a
tub, a shower, a bidet, or similar plumbing fixture.
19. A continuous load is where the __________________ current is expected to continue for
three hours or more.
a) 80% b) average c) maximum d) 125%
a. NEC® Reference: Article 100 (Continuous Load)
b. Answer: c) maximum
20. Solidly grounded is defined as connected to ground without inserting any
__________________ or impedance device.
a. NEC® Reference: Article 100 (Grounded, Solidly)
b. Answer: resistor
© 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible 3
website, in whole or in part.
, Solution and Answer Guide: Miller/Sandefur, Illustrated Guide to the NEC®, ©2024, 9780357766712, Unit 2: Definitions®
21. A(n) __________________ is a point on the wiring system at which current is taken to
supply utilization equipment.
a. NEC® Reference: Article 100 (Outlet)
b. Answer: outlet
22. A(n) __________________ is defined as the circuit conductors between the final
overcurrent device protecting the circuit and the outlet(s).
a. NEC® Reference: Article 100 (Branch-Circuit)
b. Answer: branch-circuit
23. __________________ enclosures are constructed or protected so that exposure to a
beating rain will not result in the entrance of water under specified test conditions.
a. NEC® Reference: Article 100 (Raintight)
b. Answer: Raintight
24. Continuous duty is an operation at a substantially constant load for __________________.
a) 1 hour or more b) 1½ hours or more
c) 3 hours or more d) an indefinitely long time
a. NEC® Reference: Article 100 (Duty, Continuous)
b. Answer: d) an indefinitely long time
25. Ampacity is defined as the maximum current, in amperes, that a conductor can carry
continuously under the conditions of use without exceeding __________________.
a. NEC® Reference: Article 100 (Ampacity)
b. Answer: its temperature rating
26. When a disconnecting means must be located within sight from a motor, the disconnect
must be visible and not more than __________________ ft from the motor.
a. NEC® Reference: Article 100 (In Sight From [Within Sight From, Within Sight])
b. Answer: 50
27. A building containing three dwelling units is called a(n) __________________.
a. NEC® Reference: Article 100 (Dwelling, Multifamily)
b. Answer: multifamily dwelling
28. Ground is defined as __________________.
a. NEC® Reference: Article 100 (Ground)
b. Answer: the earth
© 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible 4
website, in whole or in part.
, Solution and Answer Guide: Miller/Sandefur, Illustrated Guide to the NEC®, ©2024, 9780357766712, Unit 2: Definitions®
29. At the neutral point of the system, the __________________ of the nominal voltages from
all other phases within the system that utilize the neutral, with respect to the neutral point,
is zero potential.
a. NEC® Reference: Article 100 (Neutral Point: Informational Note)
b. Answer: vectorial sum
30. Four panelboards are in an electrical room behind locked doors. Only authorized personnel
have keys to this electrical room. In accordance with 240.24, overcurrent devices shall be
readily accessible. Since a key must be used to gain entry into the electrical room, are the
overcurrent devices in these panelboards considered readily accessible?
a. NEC® Reference: Article 100 (Accessible, Readily)
b. Answer: yes
31. A(n) __________________ is defined as an electrical power supply output, other than a
service, having no direct connection(s) to circuit conductors of any other electrical source
other than those established by grounding and bonding connections.
a. NEC® Reference: Article 100 (Separately Derived System)
b. Answer: separately derived system
32. A feeder is defined as all circuit conductors between the service equipment, the source of a
separately derived system, or other power supply source and the final __________________
overcurrent device.
a. NEC® Reference: Article 100 (Feeder)
b. Answer: branch-circuit
33. A(n) __________________ is defined as utilization equipment, generally other than
industrial, that is fastened in place, stationary, or portable; is normally built in a
standardized size or type; and is installed or connected as a unit to perform one or more
functions such as clothes washing, air-conditioning, food mixing, deep frying, and so forth.
a. NEC® Reference: Article 100 (Appliance)
b. Answer: appliance
34. A motor branch circuit includes the circuit conductors as well as the equipment between
the motor branch-circuit short-circuit and ground-fault protective device and a(n)
__________________ motor.
a. NEC® Reference: Article 100 (Branch Circuit, Motor)
b. Answer: individual
© 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible 5
website, in whole or in part.
, Solution and Answer Guide: Miller/Sandefur, Illustrated Guide to the NEC®, ©2024, 9780357766712, Unit 3: Boxes and Enclosures®
Solution and Answer Guide
MILLER/S ANDEFUR, ILLUSTRATED GUIDE TO THE NEC®, 21E, ©2024, 9780357766712; UNIT 3:
INTRODUCTION TO THE NATIONAL E LECTRICAL CODE®
TABLE OF CONTENTS
Unit 3 Competency Test ............................................................................................................................. 1
UNIT 3 COMPETENCY TEST
1. In pull boxes or junction boxes having any dimension over __________________ in., all
conductors shall be cabled or racked up in an approved manner.
a) 6 b) 12 c) 36 d) 72
a. NEC® Reference: 314.28(B)
b. Answer: d) 72; 6 (ft) x 12 (in.) = 72 in.
2. Boxes and conduit bodies in buildings shall be installed so the contained wiring and devices are
__________________.
a. NEC® Reference: 314.29(A)
b. Answer: accessible
3. What are the minimum dimensions for “X” and “Y” in the drawing below if the conductors
within the 3-in. conduit are pulled straight through the 3-in. conduit on the opposite wall and
the conductors in the 2-in. conduit are pulled through the 2-in. conduit on the adjacent wall?
All conductors are 4 AWG and larger.
a. NEC® Reference: 314.28(A)
b. Answer: “X” = 24 in., and “Y” = 12 in. The “X” dimension contains both straight and
angle pulls. Use the larger of the two. “X” (straight pull) = 3 x 8 = 24. “X” (angle pull)
3 x 6 + 2 = 20. The “Y” dimension has an angle pull only. “Y” = 2 x 6 = 12.
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