IMRADreport Revised

5/26/2018 IMRADreport Revised

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Date: 13 December 2012

To: Dr. Bruce Maylath

From: Ian Berdanier, Matthew VaughnSubject: Usability report on instructions for designing a low-voltage electrical system

ABSTRACT

Instructions for designing a low-voltage electrical system for an apartment or flat

underwent usability testing by various subjects. This test was to reveal where, if at all, the text

failed to guide the user to complete the task successfully. Subjects were chosen by experienceand familiarity with architectural plans. Data were collected by observation during the live

testing and also questionnaires filled out by each subject. With half of the subjects completing

the instructions and half failing, the test revealed major flaws with the instructions. A few steps

and some figures will be removed or modified as a direct cause from these tests. Minor technicalchanges will be made as well to the instructions.

INTRODUCTION

The task of designing a low-voltage electrical system is not practical or applicable to just

anyone. The instructions drafted by Ian Berdanier and Joan Llobera are intended to guide those

previously familiar with architectural plans in designing an electrical system. To understand the

usefulness and efficiency of the text, we conducted usability testing on their instructions with test

subjects of varying architecture backgrounds. The test encompassed readability, succinctness,

and organization. The test was also used to judge how much previous architectural experience is

needed to complete the task. Upon finding and analyzing the results, many revisions were made

to the original text.METHODS

To successfully test the instructions' usability, we selected four test subjects of varying

proficiency in reading and using architectural plans. The subjectsages ranged from 2938

(three females and one male). The subjectsexperience ranged from no experience to advanced

experience when working with architectural related documents.


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Mr. Berdanier tested three of the four subjects at his apartment, and we both tested the

final subject in the Barry Hall Library in downtown Fargo. The same protocol was used for each

subject no matter the location. First the subject was given a brief explanation of what the test was

about and what would be required of them as the test subject. The subject was then given a pre-

designed layout of a home without the electrical design (Appendix B), which they would

complete using the instructions. All test subjects used the same test plan. Next the subject was

given a copy of the instructions (Appendix A) along with the required material needed to

accomplish the task, which included a dimensioned floor plan for reference (Appendix C). The

testers then sat 1020 feet away from the subject while the subject drafted and worked through

the instructions. The testers took notes of where and when the users required help, while also

taking notes of the overall time and difficulty during the test (Appendix D).

A questionnaire (Appendix E) was given to the test subjects upon completion. The

questions asked were to better illustrate how helpful certain parts of the instructions were, and

which parts were the most important to users. Each question was asked in a scale of 05, where

0 represents a not applicable element and 5 represents an essential element to the text.We

analyzed the data following the completion of all the tests. Recurring problems and those which

impeded a subject who claimed an average or greater subject knowledge in the post-testing

questionnaire were noted as the most serious. Non-recurring problems were examined for

significance based on each subjects expected ability to complete the task, and even when

completion was not expected, whether or not a reasonable solution existed.

RESULTSTwo of the four subjects tested finished the task. Subject 1, who did not finish, was

unfamiliar with architectural plans and could not understand the jargon used in the instructions.


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Subject 2, who rated himself as advanced inarchitectural knowledge, finished the fastest with

a time of 33 minutes. Subject 3 finished the instructions at 70 minutes. The following table

further illustrates the subjectsfinal results with the initial testing. Subject 4 was a special case;

the subject completed every step except 13 and finished at 80 minutes. Step 13 was a common

problem among test subjects, thus making her incompletion of the task debatable.

Subject Age

Level Of

PreviousKnowledge

Completed

instructions?

Time taken to

complete task

#1 37 None No (Step 8 of14)

42 Min. finishstep 8

#2 38 Advanced Yes 33 Min.

#3 29 Very Little Yes 70 Min.

#4 30s AverageNo (Step 13 of

14)80 Min.

Following the initial testing, the subjects were given a questionnaire to fill out regarding

their experience with the instructions. The results from the questionnaire yielded the most

informative feedback from the whole testing experience. Many subjects found some documents

more useful than others based on experience. For example, subject 2 (who was the most

proficient) rated low importance on the floor plan and glossary, while subject 1 (who was the

least proficient) rated all elements a 4 or higher. The least highly rated element of the text was

the glossary. Only subject 1 rated it above a 2 on the importance scale. Subject 3 noted that she

did not notice that there was a glossary until after the test had ended, proving that not only was

more instruction needed to direct the subject to the glossary, but also that the glossary was not

needed to complete the task.


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0

1

2

3

4

5

1 2 3 4

How helpful was the

floor plan provided

How helpful

was the floor

plan provided

0

1

2

3

4

5

1 2 3 4

How Helpful Wasthe Glossary

How Helpful

Was the

Glossary

0

1

2

3

4

5

1 2 3 4

How helpful was the

Symbol Legend

How helpful

was the

SymbolLengend

0

1

2

3

4

5

1 2 3 4

How helpful were

the illustrations

overall

How helpful

were the

illustrations

overall

0

1

2

3

4

5

1 2 3 4

How helpful werethe instructions

overall

How helpful

were the

instructions

overall


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The instructions were overall rated as good, but there were a few recurring complaints

among the test subjects. Step 13 gave every subject trouble except for subject 1, who only made

it to step 8 before having to stop. Step 13 was a calculation added by Joan Llobera, who is co-

authoring the instructions from Barcelona, Spain. The calculation is not typically used in

American electrical designs due to the differences between American and Spanish electrical

service. Due to this confusion, subjects 2 and 3 either skipped or asked for help with that step,

while subject 4 could not continue. Another problem test subjects struggled with was drawing

the electrical panel in the location intended in the instructions. The electrical panel should be

drawn within the walls, yet in two instances it was drawn outside of the wall, although still in a

correct location. As noted above, the glossary was the lowest rated addition to the text by the

subjects. Subject 1 noted that the glossary was confusing to read and could be referred to at the

beginning. Subject 3 echoed that response, she did not even know there was a glossary until after

finishing the test. Both subjects 1 and 3 felt that figure 3 should be closer to the beginning of the

instructions; information useful for steps on the first page was not noticed until subjects turned to

page 2.

DISCUSSION

The results of the testing revealed a few major flaws and more minor flaws to the text.

Only a few steps will be altered drastically, if not deleted all together. Many of the revisions to

be made from the testresults will be to increase readability of the addition materials (i.e., the

glossary and symbol legend). The major changes to the text will result in the power calculation

in step 13 being removed for American users. It was confusing to every subject who encountered

it and caused one to quit completely. Another major revision will be to delete figure 2 entirely,

and provide the measurements directly in the text; this will be replaced with another illustration


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to provide the additional information needed for steps 1 and 2. For readability revisions, step 1

will be re-worded to better describe the panel location. Specific instructions will be given for a

socket box to be located for the refrigerator and the height requirement for the wall light box (it

will be revised to a 5 ft. minimum). Using the feedback from the questionnaire, a note will be

added on the first page guiding the user to the glossary for all words in bold-face type.Boiler

will be added to the glossary or replaced with a more suitable word. Finally an exhaust-fan

symbol will be added to the symbol legend. These revisions will help guide less-experienced

users through the instructions with greater ease and understanding.


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APPENDIX A: Instructions Tested

Introduction

The purpose of these instructions is to guide you through the process of design and installation of a low-

voltage, home electrical system.

Who should use these instructions

Draftspersons, drafting students, home designers, or others with basic knowledge of construction

drawings. Fundamental drafting skills are assumed. For Computer Aided Design (CAD) system users,

knowledge of common CAD commands is assumed.

List of materials and tools needed

1. Architectural drawing paper or Computer Aided Design (CAD) system2. A dimensioned floor plan of the home, flat, or apartment that your electrical design will derive

from

3. An undimensioned plan that is otherwise identical to the floor plan in (2) to which the electricaldesign elements will be added. If you are using a CAD system, this can be done by adding a new

layer in your digital planor making an existing electrical layer the active layer and turning off

the layer that the dimensions reside on.

4. Table or list of electrical symbols for reference or a symbol library containing electrical symbolblocks if you are using a CAD system

5. If you are not using a CAD system, you will need the following items:a. drafting pen or pencil

b. architects scalec. straight-edged. drafting triangle

Optional Items

1. calculator2. lettering guide


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To designing your home electrical system, follow these steps.

1) Locate the Electrical Panel:With your drafting pen/pencil, draw the electrical panel symbol

(Figure 1)with in a exterior wall-space near the main entrance. (A wall section that defines a

utility room or closet space is the best location.) If using CAD, select and place the electrical

panel symbol using the object snap and tracking tools.

2) Locate the socket boxes:Use the

architects scale and a drafting

pencil to mark the horizontal

points for the socket boxes. Draw

socket boxes on the electrical plan

with your drafting pen/pencil

using the appropriate symbol

(Figure 1). If using CAD, select

and place the socket symbol block

using the object-snap and tracking

tools. Use the following guide for

the minimum socket quantities.

a. Bedrooms3

b. Living Room 5

c. Kitchen6 (2 minimum

above the counter)

d. Bathrooms2(next to

the sink at the minimum distance from the bathtub as shown in Figure 2.

Figure 2

Symbol Quant it y De script ion

Elect rical Panel

Socket Box

Switch Box

Ceiling Light Box

Wall Light Box

Symbol Legend

Figure 1


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3) Locate the switch boxes: Use a drafting pencil to mark the horizontal points for the switch

boxes. Draw the switch boxes on the electrical plan with your drafting pen/pencil using the

appropriate symbol (Figure 1)on the latch-side of doors. If using CAD, select and place the

switch symbol block using the object-snap and tracking tools. Use the following guide for the

minimum switch quantities.

a. Bedrooms2 (one next to the door, and one on the opposite wall to control power to the

sockets)

b. Living Room 1

c. Kitchen1

d. Bathroom1

4) Locate the light boxes: Use the architects scale and a drafting pen/pencil to mark the horizontal

points for the light boxes. Draw the light boxes on the electrical plan with your drafting

pen/pencil using the appropriate symbol (Figure 1). If using CAD, select and place the

appropriate light symbol blocks using the object-snap and tracking tools.

5) Connect the switch boxes to the light boxes: Using a hidden line-type, draw arcuated lines

between each switch box and the light box it will energize, similar to the example in (Figure 3).

Figure 3


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6) Connect the bedroom switch box to the socket power circuit: Using a hidden line-type, draw

an arcuated line between the switch box and the nearest socket box.

7) Locate the socket boxes for high-power appliances:At a minimum, two circuits will be

dedicated to appliances. Using a drafting pen/pencil, (or if using CAD, select and place the socket

symbol block using the object-snap and tracking tools) draw socket boxes on the electrical plan

for the following appliances:

a. Oven (label as C3)

b. Washing machine, dishwasher, and electric boiler (label as C4)

8) Label your Electrical Plan: Using your straight edge and drafting pencil, draw a light line below

the drawing. Above the line, write Electrical Plan. Below the line, write the drawing scale used

(for SI 1:100 is common; for U.S. Imperial, = 10 is common).

Congratulations! You are finished drawing your Electrical Plan.

9) Draw an elevation view: Using the architects scale and drafting triangle, at an appropriate scale,

(U.S. Imperial suggest = 1 0; SI suggest 1:50) draw any portion of an interior wall that

shows the following elements.

a. socket box (0.2 m or 16 in. above the floor to the center of the box)

b. switch box (90 cm or 4 ft. above the floor to the top of the box)

c. wall light box (1 m or 5 ft. above the floor to the center of the box)

d. floor-plane

10)Add dimensions to the elevation view: Write the dimensions perpendicular to the floor-plane

and centered between the floor-plane and each socket/switch/wall light box. Draw lines from each

side of every dimension extending to the floor plane and to the box. Terminate each dimension

line at the floor plane with an arrow-head.

11)Draw a section view: Choose an appropriate scale.Using the architects scale and drafting

triangle to draw a section view of the wall through the Electrical Panel. (For SI, 1:50 is common;

for U.S. Imperial, = 1-0 is common) This view should show the following elements and

conditions:


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a. interior face of the electrical panel flush with the finished wall surface.

b. floor-plane

12)Add dimensions to the section view: Write the dimensions perpendicular to the floor plane and

centered between the floor plane and the electrical panel. Draw lines from each side of the

dimension extending to the floor plane and to the electrical panel. Terminate both lines with an

arrow-head.

13)Calculate the power requirement: List in a column the power requirements of each device and

appliance. Then calculate the sum of all these. This is the total power requirement.

This sum will determine your electrical service requirement as one of the following:

Basic Electric or Low-power (5.75 kW or less) High-power (9.2 kW or greater)

Provide this information in a note next to the electrical panel. Add a note with Circuit Data for a

heading. Under the heading write the following information:

C1Lighting Circuit C2Power-point Circuit C3Oven C4Appliances C5 - Bathroom (protected)

14) Label your drawings with the titles Electrical Elevation, andElectrical Section the same as you

did in step 8. Write the scale that you used for each drawing under its title.

Congratulations! You are finished designing your home electrical system.


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Glossary of terms

arcuated: having a random curve

digital plan: a plan [drawing] produced using Computer Aided Design (CAD) software

hidden-line: a broken or dashed line

low-voltage: the voltage used in a home. (i.e. 220-230 volts in Europe, 120 volts in the U.S.)

point: a two-dimensional position in the drawing

symbol block: the contents of a CAD symbol library


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APPENDIX B: Floor Plan to be filled out by subject


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APPENDIX C: Floor Plan (reference for subjects use)


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APPENDIX D: Observers Notes

Subject #1: Age 37, female, 42 Minutes through Step 8

-Doesnt understand the meaning of the text for placement of the electrical panel

-Needs figure 3 information on first page of instructions

-needs a note referring user to glossary for bold words and make sure all glossary words are in

bold face type

Subject #2: Age 38, male, 33 minutes to finish

-In figure 3, the 2 lines from switches to the light/exhaust fan is confusing since there is no EF

in the symbol legend

-Step 13no information to calculate power requirements

-Electrical panel within the wall space was not understood

Subject #3: Age 29, female, 70 minutes to finish

-Refrigerator circuit needs to be addressed specifically

-Boiler needs to be defined in the glossary

-Wall light box height of 5 ft. needs to be minimum

-Step 13: same as subject #2

Subject #4: Age Not Given, female, 80 minutes to reach step 13

-Added too much detail

-Step 13 caused her to stop

-Needed labeling for the elevation and section after completing them


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APPENDIX E: Questionnaire

Instructions Usability Surveyof

Designing a Low-Voltage Electrical System

Important: This is an evaluation of the instructions, not of your personal ability.

What is your level of knowledge of the subject?

None Very little Average Advanced Expert

Were you able to complete the task? Yes No

If not, how far did you get before stopping?Step: 1 2 3 4 5 6

7

8 9 10 11 12 13 14

What steps were confusing and why?

How helpful was the floor plan

provided?

How helpful was the Glossary?

How helpful was the Symbol Legend?

How helpful were the illustrations

overall?

How helpful were the instructions overall?

EssentialVery

HelpfulHelpful

Not

Helpful

Not

needed

Not

Applicable

5 4 3 2 1 0

5 4 3 2 1 0

5 4 3 2 1 0

5 4 3 2 1 0

5 4 3 2 1 0


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I s there anything that you would change about the order or l ayout of either the instructions or the il lustrati ons?

Was there any missing or i ncorrect in formation? Please Explain .

I s there anythi ng else that coul d be added or removed to impr ove the instructions?

Please provide any additi onal comments or suggestions.


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APPENDIX F: Completed Floor Plans


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IMRADreport Revised

Documents

instructions appendix

instructions usability

test plan

test wasabout

test appendix d

throughthe instructions

test encompassed readability

subject wasgiven