Nec graded project

National Electrical Code

INTRODUCTION This next portion of your program is a project-based assign- ment 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 resi- dential building applications and one industrial application. As you have learned, the National Electrical Code (NEC) is a reference manual that outlines requirements for the instal- lation 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 equip- ment 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 submis- sions for this assignment are open-book, so you can relax and focus on developing your skills in using the NEC.

National Electrical Code2

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 loca- tions 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 dia- grams before you begin this project.

Interpreting the floor plan wiring diagram for a typical res- idence, 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 stand- alone 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 learn- ing, 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.

300685300 3

Throughout this project, you’ll be required to answer questions. In fact, there are a total of 40 questions (or combi- nations 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

• 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 perform- ing 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.)

National Electrical Code4

Building Electrical Specifications:

You’ll be required to determine specific circuit loads, the min- imum service, and related conductor sizes for a single-family home with the following electrical specifications:

• Building Size: 3,800 square feet (exclusive of an unfin- ished basement, not adaptable for future use, an unfinished attic, and open porches)

• Small Appliance Branch Circuits: 3

• Laundry Branch Circuits: 1

• 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 calcula- tions 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.

500685300 5

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.

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 ser- vice 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: ________________________ _____________________________________________________________

National Electrical Code6

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 ________________________________________

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 deter- mined service size for a single-family dwelling, you’ll move to Part 2 of this project, which will examine the wiring require- ments 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 typ- ical 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

700685300 7

for lighting and simple appliances, such as entertainment sys- tems 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.

Question 8: Which article of the NEC describes the proper placement of outlets in this type of room?