Unformatted Attachment Preview
Graded Project
National Electrical
Code
National Electrical Code
INTRODUCTION
This next portion of your program is a project-based assignment designed for you to demonstrate your understanding
of the National Electrical Code and your ability to apply the
requirements and their interpretations to some typical residential building applications and one industrial application.
As you have learned, the National Electrical Code (NEC) is a
reference manual that outlines requirements for the installation of electrical equipment. The NEC is published by the
National Fire Protection Association (NFPA) and is updated
every three years to reflect changes in the industry.
The exact requirements for the installation of electrical
equipment in your area will vary depending on local regulations. You learned in your studies that the application of
the Code is rarely an exact science and that the Authority
Having Jurisdiction (AHJ) is often the final determination of
local code compliance. However, almost all electrical requirements are based on the National Electrical Code. Therefore,
it’s very important to understand the NEC thoroughly and
be able to apply it to your work.
One objective of this project is to help you appreciate that
you don’t to have to memorize the various NEC codes. You’ll
be asked to use the NEC in the way that it was designed,
as a rule book of sorts, that you will apply, step-by-step,
through some interesting and challenging problems. All of
the submissions for this assignment are open-book, so you
can relax and focus on developing your skills in using the
NEC.
Before you begin, this is a good time to simply review the
NEC and to locate the articles that you would expect to apply
to common building projects. Familiarize yourself with the
1
locations of common applications in the codes, as you’ll need
this information to complete this project. In this project,
you’ll also be looking at electrical wiring diagrams. Therefore,
you may also want to review the material on how to read
these diagrams before you begin this project.
Interpreting the floor plan wiring diagram for a typical residence, then carrying out the required wiring, is no simple
matter. To remind you of the details which must often be
addressed in a typical residential project, a wiring diagram
was included with this portion of your program. The standalone drawing shows a complete wiring diagram for one floor
of a typical residence. As you can see, this typical residence
contains many electrical outlets and devices. All of these
devices must be installed to satisfy NEC requirements. You
should note that the stand-alone drawing isn’t a part of the
actual assignments that you’ll complete; it’s simply a good
practice tool to brush-up on your print-reading skills.
In this project, you’ll use your knowledge of the NEC to
answer a variety of questions about electrical circuits.
Because this is an application-type project that involves
real-life scenarios, the project will take some time to complete. Using the NEC can be time consuming when you’re
first learning, so don’t become frustrated if this project takes
a little longer to complete than you expected.
You can submit this project in one of two ways: (1) Print this
project booklet, write your answers to the exercises inside
the printout, and mail the booklet to the school along with
the answer sheet found in the back. (2) Create a Word document of your answers, scan your marked up Figure 7, and
upload your project on the student portal.
Throughout this project, you’ll be required to answer questions.
In fact, there are a total of 40 questions (or combinations of
questions) for you to answer, including two tables to be filled
in, as well as an additional figure to be marked up. Grading
of this project will be as follows:
• Questions 1 through 40 (except Question 11 and
Question 40): 2 points each
• Question 11 (requires completion of Table 1): 5 points
2
National Electrical Code
• Markup of Figure 7: 10 points
• Question 40 (requires completion of Table 2): 5 points
Total Possible Score: 100 points
Now that you understand the basic goals of your project, let’s
get started.
PART 1: LOAD CALCULATION,
SINGLE-FAMILY DWELLING
When an electrician installs the wiring in a new building,
he or she often needs to determine the service amperage. To
accurately determine the service amperage, the electrician
must be able to calculate all of the various loads associated
with general lighting circuits, small-appliance branch circuits, and fixed-appliance circuits that supply ranges,
dryers, and HVAC systems. The NEC has specific guidelines
for performing these calculations.
In this exercise, you’ll use the Standard Method to perform
the load calculations for a one-family residence. As you work
through this exercise, please write out all of your calculations. To receive credit for the questions, you must show
exactly how you arrived at each solution. (Use scrap paper
for preliminary calculations, if you need to.)
Building Electrical Specifications:
You’ll be required to determine specific circuit loads, the
minimum service, and related conductor sizes for a singlefamily home with the following electrical specifications:
• Building Size: 3,800 square feet (exclusive of an unfinished basement, not adaptable for future use, an
unfinished attic, and open porches)
• Small Appliance Branch Circuits: 3
• Laundry Branch Circuits: 1
Graded Project
3
• Fastened-in-Place Appliances: Water heater (28 kVA),
Dishwasher (1,200 VA), Food Disposal (1,200 VA), Attic
Fans (2) @ 750 VA (1,500 VA total)
• Clothes Dryer: 5 kW
• Ranges, Ovens, Cooktops: Range 12 kW
• HVAC System: 3.5 Ton AC system 240 V, 17.9 A,
Air handler 3.3 A)
Question 1: Total General Lighting and Receptacle Load
Determine the total general lighting and receptacle load by
calculating the general lighting load, the small-appliance
branch circuit load, and the laundry branch circuit load.
Apply any demand factor as applicable. Show your calculations on the lines provided for Question 1 at the end of
Part 1 of your project.
Question 2: Fixed-in-Place Appliance Load
Determine the total fixed-in-place appliance load. Show your
calculations on the lines provided for Question 2 at the end
of Part 1 of your project.
Question 3: Dryer Load
Determine the line and the neutral load for the dryer circuit
in this residence. Show your calculations on the lines provided for Question 3 at the end of Part 1 of your project.
Question 4: Cooking Equipment Demand Load
Determine the line and the neutral load for the range in this
residence. Show your calculations on the lines provided for
Question 4 at the end of Part 1 of your project.
Question 5: HVAC Load
Determine the total AC load for the HVAC system in this
residence. Show your calculations on the lines provided for
Question 5 at the end of Part 1 of your project.
Question 6: Largest Motor Load
Determine the largest motor load for this residence. Do not
consider the AC unit as a motor load. Show your calculations on the lines provided for Question 6 at the end of
Part 1 of your project.
4
National Electrical Code
Question 7: Total Demand, Service Size and Service
Conductors
Based on your calculations for questions 1–6, determine
the total demand in VA for this residence, the minimum
service size, and the minimum conductor sizes (THW) for
the ungrounded and grounding electrode conductors (assume
the neutral conductor to be the same as the ungrounded
conductor). Show your calculations on the lines provided
for Question 7 at the end of Part 1 of your project.
ANSWERS AND CALCULATIONS
FOR PART 1
Answer to Question 1:
General Lighting and Receptacle Load:
____________________
Small-Appliance Branch Circuit Load:
____________________
Laundry Branch Circuit Load:
____________________________
Total General Lighting and Receptacle Load ________________
Answer to Question 2:
Total Fixed-in-Place-Appliance Load:
______________________
____________________________________________________________
Answer to Question 3:
Dryer Demand Load: Line
__________Neutral
____________
____________________________________________________________
Answer to Question 4:
Cooking Equipment Demand Load: Line ______Neutral ____
____________________________________________________________
Answer to Question 5:
HVAC Demand Load ______________________________________
____________________________________________________________
Graded Project
5
Answer to Question 6:
Largest Motor Demand Load
______________________________
____________________________________________________________
Answer to Question 7:
Total Demand
____________________________________________
Minimum Service Size
____________________________________
Minimum Size Ungrounded Conductor
____________________
Minimum Size Grounding Electrode Conductor ____________
PART 2: RESIDENTIAL ROOM
WIRING
Now that you’ve completed your load calculations and determined service size for a single-family dwelling, you’ll move to
Part 2 of this project, which will examine the wiring requirements for 3 basic residential room types: general living
space (living rooms, dens, family rooms), a kitchen, and a
bathroom.
General Living Space
To begin Part 2 of your project, you’ll examine some general
living space, one of the most basic wiring assignments in a
home. Figure 1 illustrates some wiring that’s found in a typical
living room. Study this diagram carefully and review the NEC
codes that apply to this type of room. Note that several outlets
are shown in Figure 1. These outlets are typically used for
lighting and simple appliances, such as entertainment systems
and personal computers. The placement of the outlets in the
room is important. Once you’ve reviewed the NEC articles
that apply to this room, answer the following questions.
6
National Electrical Code
Question 8: Which article of the NEC describes the proper
placement of outlets in this type of room?
____________________________________________________________
Question 9: Part 1: According to the NEC, what is the
maximum wall space that’s allowed between two adjacent
outlets? ____________ Part 2: How large must a wall space
be to require an outlet? ____________ Part 3: Should an outlet located at 7-feet up the wall from the floor, used to power
a light fixture, be included in wall space requirement?
____________________________________________________________
Question 10: If the outlets in this room are supplied by a
single 15A or 20A circuit, what is the maximum current that
can be supplied (in amps) to a cord-and plug connected load?
____________________________________________________________
S
FIGURE 1—Refer to
this diagram while
you’re working on
questions related to
the general living
space.
LIVING ROOM
Graded Project
CLOSET
L
7
Question 11: Look at the items listed in Table 1. Indicate
which items are considered to be wall space by the NEC, and
which items aren’t considered to be wall space. (Place an “X”
in the appropriate column next to each item.)
Table 1
Item
Considered to Be
Not Considered to Be
Wall Space
Wall Space
Fireplace
Fixed glass panel
Sliding segment of glass door
Door opening
Bar-type counter
Wall space less than 1 foot wide
Wall space 3 feet wide
Doorway
Fixed cabinet
Question 12: Part 1: In Figure 1, note that a switch is located
close to the door. This switch operates an overhead light fixture. This arrangement is a requirement of the NEC. Which
article of the NEC covers this regulation for a room of this
type? ____________ Part 2: Other than the switch shown in
Figure 1, what alternative way can be used to meet the NEC
requirement? ____________
Question 13: If the branch circuits supplying the receptacles
in the figure are rated at 20 A, what is the minimum ampacity rating of the conductors in the branch circuit?
____________________________________________________________
Question 14: How many branch circuits that supply the
room shown in Figure 1 are required to be GFCI protected
according to the NEC?
____________________________________________________________
8
National Electrical Code
Kitchen
Now, you’ll apply your knowledge of the NEC to a simple
kitchen layout. Figure 2 shows some wiring in a typical
kitchen found in a single-family dwelling. Electrical circuits
in kitchens supply current to small appliances, electric
ranges, dishwashers, and refrigerators; as well as lighting
and general branch-circuit outlets.
The NEC is very specific about the installation of wiring in
kitchen areas. Study the wiring carefully in Figure 2 and
look up the codes that apply to this situation in your NEC
codebook. Then, answer the following questions.
FIGURE 2—Refer to this
diagram when you’re
working on questions
related to the kitchen.
S4
S3
TL
L
ISLAND
REF
S3
KITCHEN
S4
Question 15: What section of the NEC covers the use of
GFCI-protected outlets in a residential kitchen?
____________________________________________________________
Question 16: How many of the outlets shown in Figure 2 are
required to be GFCI protected by the NEC? Identify the location of the outlets you selected on the figure.
____________________________________________________________
Question 17: What is the maximum distance that can separate the two outlets located to the right of the sink in the
figure?
____________________________________________________________
Graded Project
9
Question 18: The outlets along the countertop are to be
used for small appliances. What is the minimum number of
branch circuits that would be needed to supply just these
small-appliance outlets?
____________________________________________________________
Question 19: Part 1: What is the maximum distance (in feet)
that the receptacle intended for the refrigerator can be from
that appliance? ____________ Part 2: Name two common
kitchen appliances that may require receptacle locations to
be closer than required by 210.50 due to restrictions on cord
lengths? ____________
Question 20: What is the minimum circuit protection (in
amps) and wire size needed for each of the required smallappliance circuits?
____________________________________________________________
Question 21: In Figure 2, note that an electrical outlet is
shown on the island in the kitchen area. Is this outlet
required by the NEC, or does it represent an NEC violation?
Briefly explain your answer.
____________________________________________________________
Question 22: Looking again at the island counter in the
kitchen. If the countertop above the outlet was extended 12
inches beyond the base of the cabinet to allow bar-stool seating at the counter, would that change the NEC status of the
outlet? Briefly explain your answer.
____________________________________________________________
Question 23: Suppose that a built-in dishwasher is to be
installed in this kitchen. Does the NEC allow the dishwasher
to be connected to the existing small-appliance circuits?
____________________________________________________________
Question 24: Can any of the receptacles required for the
countertop space be mounted in the actual countertop? Cite
an NEC section and condition to support your answer.
____________________________________________________________
10
National Electrical Code
Question 25: Does the NEC allow the lighting circuit for a
kitchen to be attached to the small-appliance circuits?
____________________________________________________________
Question 26: What is the maximum height that the outlets
on either side of the sink can be installed above the countertop surface?
____________________________________________________________
Question 27: If the distance between the outlets on either
side of the range in Figure 2 is less than 4 feet, are both outlets required per the NEC? Briefly explain your answer.
____________________________________________________________
Bathroom
You’ve worked through the general living area and the
kitchen, and next you’ll look at the electrical wiring of a
small residential bathroom. Figure 3 shows some wiring
that’s to be installed in a bathroom. Study the wiring shown
in the figure carefully, and review the NEC articles that apply
in these situations. Once you’ve reviewed the appropriate
articles, answer the following questions about this wiring
diagram.
FIGURE 3—Refer to this
diagram while you’re
working on questions
related to the bathroom.
L
SS
Graded Project
11
Question 28: What section of the NEC covers the use of
GFCI-protected outlets in a residential bathroom?
____________________________________________________________
Question 29: How many of the outlets shown are required to
be GFCI protected by the NEC? Circle your selections (if any)
on Figure 3.
____________________________________________________________
Question 30: In what situation would the NEC allow any one
of the outlets in this bathroom to supply power to an outlet
in another room?
____________________________________________________________
Question 31: The receptacle near the basin in figure can be
mounted on the countertop and, if a listed assembly, in the
countertop. In what position may the receptacle not be
mounted?
____________________________________________________________
Question 32: Looking again at the receptacle near the basin.
What is the maximum distance the outlet can be away from
the outside edge of the basin?
____________________________________________________________
Question 33: You’re rewiring the bathroom in Figure 3 as
part of a remodeling project. The customer requests a GFCI
receptacle on the back wall of the bathtub area, 5-feet from
the top edge of the tub. Should you comply with the customer request? Site an NEC section to support your answer.
____________________________________________________________
Question 34: Does the NEC allow the lighting circuit in the
bathroom area to be connected to the same circuit as the
outlet receptacles?
____________________________________________________________
12
National Electrical Code
PART 3: BRANCH CIRCUIT
SIZING
You’ve had a chance to test your skills at load calculations
and service sizing, as you’ve just completed your evaluation
of some basic room wiring. The next important skill you’ll
practice is the proper sizing of the various branch circuits
that feed specialized equipment such as ranges, and water
heaters.
In Part 3 of your project, you’ll determine the proper size of
the branch circuits for three wiring scenarios involving cooking equipment.
As you work through this exercise, please show all of your
calculations on the calculation sheet at the end of Part 3. To
receive credit for the questions, you must show exactly how
you arrived at each solution. (Use scrap paper for preliminary calculations, if you need to, before you transfer your
final calculations to the calculation sheet at the end of
Part 3.)
Example 1: Suppose that you’re working in a home that
has a 15 kW oven that operates on 240 V. The oven is on
a branch circuit by itself, as shown in Figure 4.
FIGURE 4—Diagram for
Example 1
PANEL BOX
15 kW OVEN
Question 35: What is the demand load for this circuit? (Show
all of your calculations on the calculation sheet at the end of
Part 3.)
____________________________________________________________
Graded Project
13
Question 36: What size TW copper conductor should be used
for the branch circuit? (Show all of your calculations on the
calculation sheet at the end of Part 3.)
Example 2: Suppose that you’re working in a kitchen that
contains one 8 kW counter-mounted cooking unit and two
6 kW wall-mounted ovens. All three appliances are served by
the same 240 V branch circuit. This situation is illustrated
in Figure 5.
6 kW OVEN
8 kW COOKTOP
BRANCH CIRCUIT
6 kW OVEN
FIGURE 5—Diagram for Example 2
Question 37: What would be the demand load for this
branch circuit? (Show all of your calculations on the calculation sheet at the end of Part 3.)
Question 38: What is the minimum-size TW copper conductor that should be used for this branch circuit? (Show all of
your calculations on the calculation sheet at the end of
Part 3.)
Example 3: Suppose that you’re working in a building that
contains commercial kitchen equipment. The kitchen contains three 3 kW ovens, a 20 kW water heater, and a 3 kW
deep fryer, as shown in Figure 6.
14
National Electrical Code
DEEP FRYER
3 kW
WATER HEATER
20 kW
OVEN
3 kW
OVEN
3 kW
OVEN
3 kW
FIGURE 6—Diagram for Example 3
Question 39: What would be the demand load for all of these
items? (Show all of your calculations on the calculation sheet
at the end of Part 3.)
ANSWERS AND CALCULATIONS
FOR PART 3
Show all work for Part 3 here.
Answer to Question 35: ____________________________________
Show all calculations to determine the demand load for
Question 35:
____________________________________________________________
____________________________________________________________
Answer to Question 36: ____________________________________
Show all calculations to determine the wire size for
Question 36:
____________________________________________________________
____________________________________________________________
Graded Project
15
Answer to Question 37: ____________________________________
Show all calculations to determine the demand load for
Question 37:
____________________________________________________________
____________________________________________________________
Answer to Question 38: ____________________________________
Show all calculations to determine the wire size for
Question 38:
____________________________________________________________
____________________________________________________________
Answer to Question 39: ____________________________________
Show all calculations to determine the demand load for
Question 39:
____________________________________________________________
____________________________________________________________
PART 4: DETERMINING
RECEPTACLE LOCATIONS
In this exercise, you’ll evaluate the floor plan for general living
space in a typical home and determine the proper locations
for the electrical outlets in the room. The NEC covers not
only the electrical wiring of devices, but also (in many cases)
the proper location for each device.
Look at the living room shown in Figure 7. Imagine that you
want to install in this room the minimum number of outlets
required by the NEC. To complete the exercise, you’ll need to
determine the minimum number of outlets needed for this
room, and indicate the correct location where they should be
installed in the room. You’ll mark the location of the outlets
directly on Figure 7 in your project booklet.
16
National Electrical Code
To receive full credit for this exercise, you’ll need to do the
following four things:
1. Indicate the location of each outlet in the figure by using
the appropriate symbol
2. Indicate the distance that the outlet should be placed
along the adjoining wall
3. Show how the branch circuit(s) would be connected
4. Indicate the proper spacing between outlets to meet NEC
code requirements
5 ft
3 ft
3 ft
GLASS SLIDER
5 ft
GLASS FIXED
4 ft
8 ft
FIREPLACE
7 ft
DOORWAY
5 ft
4 ft
4 ft
16 ft
FIGURE 7—Mark this diagram with receptacle locations and symbols.
Graded Project
17
Keep in mind that there are several different ways that this
job can be done correctly. However, remember that you’re
trying to install the minimum number of outlets. Therefore,
you may have to try several different patterns to determine
which configuration uses the minimum number of outlets.
(Try sketching your ideas on scrap paper first; then, mark
your final answers directly on Figure 7.)
PART 5: NEC CODE VIOLATIONS
Part 5 of your NEC project will be similar to previous exercises in that you’ll be asked to evaluate simple electrical
wiring diagrams. However, these diagrams will contain NEC
violations. It will be your job to locate and identify the code
violations.
For example, suppose that you’re looking at a kitchen wiring
diagram and notice that GFCI outlets weren’t placed near the
sink. Well, the NEC requires that any outlet near water must
be fitted with a GFCI outlet for protection from electrical
shock. For the exercise, you would recognize that this installation violates the NEC; you would then describe the violation
and reference the article or section of the NEC that supports
your answer.
The best approach to completing this exercise is to look over
the illustrations in the project very carefully, paying attention
to each and every detail. Then, use your knowledge of the
NEC to check each circuit shown. Checking each circuit in
an organized manner is the fastest and easiest way to complete the project.
Now, you’re ready to begin this part of your project. Carefully
study the wiring diagrams shown in Figures 8 through 12.
At least one NEC violation is shown in each diagram. Identify
each violation, and then describe the violation in Table 2.
You’ll also need to indicate which article of the NEC is
involved in the violation.
18
National Electrical Code
To be sure that you understand how this exercise works, one
example has been completed for you in the table. Figure 8
shows a typical residential bathroom. As you can see in the
figure, the outlet receptacle next to the basin isn’t GFCI protected. This is a violation of the NEC. (Article 210.8(A) (1)
indicates that all electrical outlets in bathroom areas must
have GFCI protection.) So, you would describe the problem
as shown in the first line of Table 2.
Question 40: Review the figures, note all NEC violations
in each one, and determine which NEC article has been violated. Use this information to complete the remainder of
Table 2.
____________________________________________________________
FIGURE 8—Note any NEC
violations in Table 2.
S S
L
Table 2
Figure Number
Description of the NEC Violation
NEC Article Violated
8
Outlet not GFCI protected
Article 210.8(A)(1)
9
10
11
12
Graded Project
19
FIGURE 9—Note any
NEC violations in Table 2.
CLOSET
8 ft
8 ft
6 ft
BEDROOM #3
6 ft
8 ft
8 ft
14/2
15 A
120 V
FIGURE 10—Note any
NEC violations in Table 2.
12/2
20 A
120 V
GFCI
BATH #1
S
L
L
BATH #2
S
GFCI
20
National Electrical Code
FIGURE 11—Note
any NEC violations
in Table 2.
12 ft
12/2
20 A
120 V
22 ft
12 ft
BEDROOM #1
8 ft
6 ft
6 ft
S
12/2
20 A
120 V
14/2
15 A
120 V
GFCI
3 ft
4 ft
GFCI
4 ft
GFCI
GFCI
FIGURE 12—Note
any NEC violations
in Table 2.
6 ft
KITCHEN
L
L
6 ft
S
3 ft
Graded Project
S
3 ft
21
SUBMITTING YOUR WORK
Mail-In
To mail-in your project, once you’ve completed all parts of
this project and answered all of the questions, fill out your
name and student number on the Answer Sheet on the following page. Then, using the address provided on the Answer
Sheet, mail the entire lesson booklet to the school.
Be sure to keep a copy of your completed assignment!
Online
You can also submit your graded project online:
1. On your computer, save a revised and corrected version
of your project. Be sure to include your student number
and exam number on your saved documents.
2. Go to http://www.pennfoster.edu and log in.
3. Go to your student portal.
4. Click on Take Exam next to the lesson you’re working
on.
5. Enter your email address in the box provided. (Note:
This information is required for online submission.)
6. Attach your file as follows:
a. Click on the Browse box.
b. Locate the file you wish to attach.
c. Double-click on the file.
d. Click on Upload File.
e. Repeat these steps for all documents.
7. Click on Submit Files.
22
National Electrical Code
ANSWER SHEET
FOR YOUR INSTRUCTOR’S USE
GRADE
GRADED BY
EXAMINATION NUMBER
STUDENT NUMBER:
PLEASE PRINT
NAME
00683100
National Electrical Code
Graded Project
________________________________________________________________
ADDRESS ________________________________________________________________
CITY
________________________________________________________________
STATE/PROVINCE
ZIP/POSTAL CODE
Check if this is a new address
—
PHONE
CUT ALONG THIS LINE
Graded Project
National Electrical Code
Answer Sheet
Grading Criteria
Your answers will be graded on the following criteria.
Questions 1–40 (80 pts.)
_______
Question 11 (5 pts.)
_______
Figure 7 (10 pts.)
_______
Question 40 (5 pts.)
_______
Total Score
_______
When you’ve completed the exercises in this project booklet, fill out the top of this Answer Sheet. Then mail the
entire booklet (including this Answer Sheet) to
Penn Foster
Student Service Center
925 Oak Street
Scranton, PA 18515
Attention: Education Department, Electrician Project
Comments ____________________________________________________________________
____________________________________________________________________________
____________________________________________________________________________
____________________________________________________________________________
Graded Project
23