NCCER Module 26111-23 PT 11

Electrical

Module 26111-23

Residential Wiring

Copyright © 2024 by NCCER, Alachua, FL 32615. Published by Pearson. All rights reserved.

1.0.0 Sizing the Residential Electrical Service

Module 26111-23 – Residential Wiring

Objective

1. Explain how to size the electric service for a dwelling.

a. Describe electric service and appliance loads.

b. Summarize how to apply demand factors.

c. Describe how to size the load center.

Module 26111-23 – Residential Wiring

Performance Task

1. Given the size and list of installed major appliances for a residential
dwelling, demonstrate or explain how to:

• Compute lighting, small-appliance, and laundry loads.

• Compute the loads for large appliances.

• Determine the number of branch circuits required.

• Size and select the service-entrance conductors, panelboard, and
protective devices.

Module 26111-23 – Residential Wiring

1.0.0–1.1.0 Residential Electric Service Load

In a residential occupancy, the utility
company provides a 120/240V,
single-phase service entrance.
•

The service and feeder are
three-wire.
•

Each branch is either two- or
three-wire.
•

Each safety switch, the service
equipment, and panelboards
are three-wire with a solid
neutral.

Module 26111-23 – Residential Wiring

1.1.1 Calculating the Residential Electric Service Load

The first step in calculating the service load is to look at the floor plan.

Module 26111-23 – Residential Wiring

1.1.2 Calculating the General Lighting Load

•

The general lighting load includes general-use receptacles of 20A or less,
including bathrooms and garages, outdoor receptacles, and lighting
outlets in the dwelling.

•

To calculate the general load, first find the square footage of the living
area and multiply it by 3VA/ft2.

Module 26111-23 – Residential Wiring

1.1.3 Calculating the Small-Appliance Load

•

Next, calculate the small-
appliance branch circuits.

•

NEC Section 210.11(C)(1)
requires at least two 120V, 20A
small-appliance branch circuits.

Module 26111-23 – Residential Wiring

1.1.4 Calculating the Laundry Circuit Load

•

Next, compute the laundry circuit
load.

•

NEC Section 210.11(C)(2) requires
one dedicated 20A branch circuit for
the exclusive use of the laundry area.

Module 26111-23 – Residential Wiring

1.1.5 Calculating the Lighting Demand Factors

After calculating the subtotal of general lighting loads, use Boxes 8 through
12 and NEC Table 220.45 to calculate the total demand for general lighting
loads.

Module 26111-23 – Residential Wiring

1.1.6 Calculating the Fixed Appliance Load

•

List the fixed appliances and their loads.

•

Then use NEC Section 220.53 to determine the demand factor.

Module 26111-23 – Residential Wiring

1.1.7 Calculating Other Loads

•

List the electric range, electric
dryer, and any other loads.

•

Add 25% of the largest motor.

•

Calculate the total VA demand
by adding the totals from:
–

General Lighting Load
–

Fixed Appliance Load
–

The sections from Other
Loads.

Module 26111-23 – Residential Wiring

1.1.8 Required Service Size

The final step is to calculate the required service size.

Module 26111-23 – Residential Wiring

1.2.0 Applying Demand Factors

•

A demand factor is the maximum amount of volt-ampere load that you
expect at any given time, compared to the total connected load of the
circuit.

•

The maximum demand of a feeder circuit is calculated by multiplying the
connected load by the demand factor.

Module 26111-23 – Residential Wiring

1.2.1 Demand Factors for Electric Ranges

The method for calculating
the demand factors for
electric ranges depends on
whether you are using NEC
Article 220, Part III or Part
IV and the type of dwelling.

NEC® Part

NEC® Code

NEC® Section Name

NEC Article 220, Part
III, Feeder and Service
Load Calculations

NEC
Section
220.55

Electric Cooking
Appliances in
Dwelling Units and
Household Cooking
Appliances Used in
Instructional
Programs

NEC Article 220, Part
IV, Optional Feeder and
Service Load
Calculations

NEC
Section
220.82

Dwelling Unit

NEC Article 220, Part
IV, Optional Feeder and
Service Load
Calculations

NEC
Section
220.83

Existing Dwelling
Unit

Module 26111-23 – Residential Wiring

1.2.2 Calculating Demand Factors for Neutral Conductors

Step 1 Calculate the neutral conductor size for the net general lighting and
small-appliance load and enter it in Box 13 on the worksheet.

Step 2 Calculate the neutral conductor size for the fixed-appliance loads by
totaling the 120V fixed-appliance loads.

Step 3 Calculate the neutral conductor size for the other loads.

Step 4 Calculate the total neutral demand and enter it in Box 34 on the
worksheet.

Step 5 Calculate the total phase-to-phase amperes and enter it in Box 36 on
the worksheet.

Step 6 Enter the AWG; refer to NEC Section 110.14(C)(1) or NEC Table 310.16.

Module 26111-23 – Residential Wiring

1.3.0 Sizing the Load Center

•

The load center is a panelboard
that distributes the electricity
coming from the source to branch
circuits.

•

Use the calculation worksheet to
determine the number and type of
circuits needed in the load center
for each section.

Module 26111-23 – Residential Wiring

1.3.1 Using Ground Fault Circuit Interrupters

•

A GFCI is a safety device installed
in place of a regular outlet.
–

It protects personnel by de-
energizing a circuit when a
ground fault current exceeds
the values established for a
Class A device.

•

GFCI circuit breakers may also be
used.

Module 26111-23 – Residential Wiring

1.3.2–1.3.3 Surge Protective Devices

•

Arc fault circuit interrupters (AFCIs) are another type of safety device.
–

NEC Section 210.12(B) specifies which branch circuits shall have
AFCI protection.

•

NEC Section 230.67(A) and (B) requires dwelling unit services to be
provided with a surge protective device (SPD) and specifies where it be
located.

Module 26111-23 – Residential Wiring

Trade Terms (1 of 3)

Appliances: Equipment designed to use electricity for a particular purpose.
For example, you use a refrigerator to produce cold and a hair dryer to
produce heat. Appliances are usually self-contained and produced in
standard sizes or types. Most appliances are not for industrial use.

Branch circuit: The portion of a wiring system extending beyond the final
overcurrent device protecting a circuit.

Feeder: Any circuit conductor between the service equipment, the source of
a separately derived system, or other power supply source and the final
branch circuit overcurrent device.

Module 26111-23 – Residential Wiring

Trade Terms (2 of 3)

Grounded conductor: A system or circuit conductor that is intentionally
grounded.

Grounding electrode conductor: A conductor that connects either the
system grounded conductor or the equipment to a grounding electrode or a
point on the grounding electrode system.

Load center: A type of panelboard normally located at the service entrance
of a residential installation. It sometimes contains the main disconnect.

Module 26111-23 – Residential Wiring

Trade Terms (3 of 3)

Service entrance: The point where power is supplied to a building (including
the equipment used for this purpose). The service entrance includes the
service main switch or panelboard, metering devices, overcurrent protective
devices, and conductors/raceways for connecting to the power company’s
conductors.

Service-entrance conductors: The conductors between the point of
termination of the overhead service drop or underground service lateral and
the main disconnecting device in the building.

Switch: A mechanical device used for turning an electrical load on and off.

Module 26111-23 – Residential Wiring

1.0.0 Section Review Question 1

1. A small residence has a floor area of 900 ft2. What is its general lighting
load?

a. 900VA

b. 1,800VA

c. 2,700VA

d. 3,600VA

Module 26111-23 – Residential Wiring

1.0.0 Section Review Question 1 Answer

1. A small residence has a floor area of 900 ft2. What is its general lighting
load?

a. 900VA

b. 1,800VA

c. 2,700VA

d. 3,600VA

Module 26111-23 – Residential Wiring

1.0.0 Section Review Question 2

2. If a dwelling has two kitchen areas, the total small-appliance branch
circuits required would be _____.

a. one at 1,500VA each

b. two at 1,500VA each

c. three at 1,500VA each

d. four at 1,500VA each

Module 26111-23 – Residential Wiring

1.0.0 Section Review Question 2 Answer

2. If a dwelling has two kitchen areas, the total small-appliance branch
circuits required would be _____.

a. one at 1,500VA each

b. two at 1,500VA each

c. three at 1,500VA each

d. four at 1,500VA each

Module 26111-23 – Residential Wiring

1.0.0 Section Review Question 3

3. According to NEC Table 220.54, a household with two dryers has a
demand factor of _____.

a. 100%

b. 85%

c. 75%

d. 65%

Module 26111-23 – Residential Wiring

1.0.0 Section Review Question 3 Answer

3. According to NEC Table 220.54, a household with two dryers has a
demand factor of _____.

a. 100%

b. 85%

c. 75%

d. 65%

Module 26111-23 – Residential Wiring

1.0.0 Section Review Question 4

4. A lighting load of 2,700VA at 120V has an amperage of _____.

a. 20A

b. 22.5A

c. 30A

d. 36.5A

Module 26111-23 – Residential Wiring

1.0.0 Section Review Question 4 Answer

4. A lighting load of 2,700VA at 120V has an amperage of _____.

a. 20A

b. 22.5A

c. 30A

d. 36.5A

Next…

2.0.0
Grounding and Bonding

Read Sections 2.0.0 through 2.3.0. Complete the 2.0.0 Section
Review.

Electrical

Module 26111-23

Residential Wiring

Copyright © 2024 by NCCER, Alachua, FL 32615. Published by Pearson. All rights reserved.

2.0.0 Grounding and Bonding

Module 26111-23 – Residential Wiring

Objective

2. Identify grounding requirements for a residential electrical system.

a. Explain how to size grounding electrodes.

b. Explain how to size the main bonding jumper.

c. Describe how to install the equipment grounding system.

Module 26111-23 – Residential Wiring

Performance Tasks

There are no Performance Tasks associated with this section.

Module 26111-23 – Residential Wiring

2.0.0–2.1.0 Grounding and Bonding

•

Grounding and bonding protect people and equipment.
–

Grounding is connecting an electrical system to the earth.
–

Bonding is connecting the noncurrent-carrying conductive parts of a
system together to create a conductive path.

•

Two classifications of grounding:
–

System grounding
–

Equipment grounding

Module 26111-23 – Residential Wiring

2.1.1 Examining a Residential Grounding System

•

The NEC® allows the grounded
conductor in an electric service to be
smaller than the ungrounded
conductor. It must be sufficient to
carry fault currents back to the source.

•

NEC Section 250.24(A)(1) specifies
how the grounding electrode be
connected in a panelboard.

Module 26111-23 – Residential Wiring

2.1.2 Using Grounding Electrodes

•

NEC Article 250, Part III lists the
requirements for connecting an
electric service to the grounding
electrode system of a building or
structure.

•

Often in residential construction,
the only grounding electrode
available is the metal underground
water piping system.
–

This must be supplemented
with another electrode.

Module 26111-23 – Residential Wiring

2.1.3 Grounding Electrode Installations

•

NEC Section 250.53(A)(1) requirements for rod, pipe, and plate
electrodes include:
–

Buried below the permanent moisture level
–

Free from any nonconductive coatings, such as paint or enamel

•

A rod or pipe electrode may be driven at a 45° angle if rock is encountered
or may be laid in a trench that is at least 30" deep.

•

NEC Section 250.53(A)(2) specifies when a supplemental electrode is
required.

Module 26111-23 – Residential Wiring

2.1.4 Grounding Electrode Conductor (GEC)

NEC Section 250.62 covers the requirements for GECs that connect the
neutral (grounded conductor) at the panelboard neutral bus to the grounding
electrodes.
•

Must be made of copper, aluminum, or copper-clad aluminum.
•

Must be protected against corrosion.
•

May be either solid or stranded and insulated, covered, or bare.
•

It does not have to be identified using the color green or green with
yellow stripes if insulated.

Module 26111-23 – Residential Wiring

2.1.5 Installing GECs

NEC Section 250.64
covers the installation
requirements for GECs.

Module 26111-23 – Residential Wiring

2.1.6 Connecting GECs

NEC Section 250.70 requires
that the GEC must be
connected to electrodes using
exothermic welding, listed
pressure connectors, listed
clamps, listed lugs, or other
listed means.

Module 26111-23 – Residential Wiring

2.1.7 Sizing GECs

•

For sizing grounding electrode conductors, NEC Section 250.66 requires
you to use the area of the largest service-entrance conductor or the
equivalent area for paralleled conductors.

•

Use NEC Table 250.66 to find the minimum size GEC and any bonding
jumpers you need to interconnect grounding electrodes.

Module 26111-23 – Residential Wiring

2.1.8 Air Terminals (Lightning Protection)

•

NEC Section 250.60 covers using air terminal conductors and driven
pipes, rods, or plate electrodes for grounding air terminals.

•

NEC Section 250.106 requires they be bonded to the structure’s wiring
and equipment grounding electrode system.

Module 26111-23 – Residential Wiring

2.2.0 Main Bonding Jumper

•

The main bonding jumper (MBJ) is the conductor that connects the
grounded circuit conductor and the equipment grounding conductor.

•

The MBJ allows any ground fault in the branch circuits and feeders of the
electrical system to travel back to the source of supply at the utility.

Module 26111-23 – Residential Wiring

2.2.1–2.2.2 Methods of Bonding at the Service

•

NEC Section 250.92(A) requires electrical continuity at the service.

•

NEC Section 250.92(B) includes methods that should be used to ensure
the electrical continuity of the service equipment, raceways, and
enclosures.

Module 26111-23 – Residential Wiring

2.2.3–2.2.5 Bonding of Other Piping Systems

•

Intersystem bonding termination (IBT) devices are covered in NEC
Section 250.94(A).

•

NEC Section 250.104(A) sets the rules for how to bond a metallic water
piping system.

•

NEC Section 250.104(B) covers how to bond other types of piping
systems.

Module 26111-23 – Residential Wiring

2.3.0 Installing the Equipment Grounding System

•

NEC Article 250, Part VI covers
equipment grounding and equipment
grounding conductors.

•

NEC Section 250.110 lists the
conditions which require the exposed
metal parts of fixed equipment to be
grounded.

•

NEC Section 250.118 covers the
types of conductors that may be
used.

Module 26111-23 – Residential Wiring

Trade Terms (1 of 3)

Bonding bushing: A special conduit bushing equipped with a conductor
terminal to accept a bonding jumper. It has a screw or other sharp device to
bite into the enclosure wall. This lets it bond the conduit to the enclosure
without a jumper when there are no concentric knockouts left in the wall of
the enclosure.

Bonding jumper: A bare or green insulated conductor used to ensure
electrical conductivity between metal parts connected electrically. Bonding
jumpers often go from a bonding bushing to the service-equipment
enclosure. They also provide a path around concentric knockouts in an
enclosure wall and can be used to bond one raceway to another.

Module 26111-23 – Residential Wiring

Trade Terms (2 of 3)

Equipment grounding conductor: A conductive path part of an effective
ground fault current path that connects normally noncurrent-carrying metal
parts of equipment together to the system ground conductor, the grounding
electrode conductor, or both.

Grounding electrode: A conducting object through which there is a direct
connection to earth.

Service drop: The overhead conductors through which electrical service is
supplied. They are located between the last power company pole and the
point of connection to the service facilities at the building.

Module 26111-23 – Residential Wiring

Trade Terms (3 of 3)

Service lateral: The underground conductors through which electrical
service is supplied. They are located between the power company’s
distribution facilities and the first point of connection to the building or area
service facilities.

Ungrounded conductor: A circuit conductor that carries current to the load.

Module 26111-23 – Residential Wiring

2.0.0 Section Review Question 1

1. When used as a grounding electrode, a ground ring must be at least
_____.

a. 5' (1.5 m) long

b. 10' (3 m) long

c. 15' (4.5 m) long

d. 20' (6 m) long

Module 26111-23 – Residential Wiring

2.0.0 Section Review Question 1 Answer

1. When used as a grounding electrode, a ground ring must be at least
_____.

a. 5' (1.5 m) long

b. 10' (3 m) long

c. 15' (4.5 m) long

d. 20' (6 m) long

Module 26111-23 – Residential Wiring

2.0.0 Section Review Question 2

2. When a screw is used as a main bonding jumper, its finish color must be
_____.

a. white

b. green

c. blue

d. black

Module 26111-23 – Residential Wiring

2.0.0 Section Review Question 2 Answer

2. When a screw is used as a main bonding jumper, its finish color must be
_____.

a. white

b. green

c. blue

d. black

Module 26111-23 – Residential Wiring

2.0.0 Section Review Question 3

3. Information on equipment grounding for computers is found in _____.

a.

NEC Section 250.112

b.

NEC Section 250.114

c.

NEC Section 250.116

d.

NEC Section 250.118

Module 26111-23 – Residential Wiring

2.0.0 Section Review Question 3 Answer

3. Information on equipment grounding for computers is found in _____.

a.

NEC Section 250.112

b.

NEC Section 250.114

c.

NEC Section 250.116

d.

NEC Section 250.118

Next…

3.0.0
Installing Service-Entrance Equipment

Read Sections 3.0.0 through 3.2.0. Complete the 3.0.0 Section
Review.

Electrical

Module 26111-23

Residential Wiring

Copyright © 2024 by NCCER, Alachua, FL 32615. Published by Pearson. All rights reserved.

3.0.0 Installing Service-Entrance Equipment

Module 26111-23 – Residential Wiring

Objective

3. Explain how to install service-entrance equipment.

a. Identify the service drop location.

b. Describe how to select the panelboard location.

Module 26111-23 – Residential Wiring

Performance Task

2. Using an unlabeled diagram of a panelboard, label the lettered
components.

Module 26111-23 – Residential Wiring

3.0.0–3.1.0 Locating a Service Drop

•

Electric service is one of the
last parts installed but should
be planned from the very
beginning.

•

You must know where to
locate the service drop,
electric meter, and load
center before roughing in the
electrical wiring.

Module 26111-23 – Residential Wiring

3.1.1 Vertical Clearances of Service Drops

NEC Section 230.24(B) specifies the
distances by which service drop
conductors must clear the ground
according to different conditions.

Module 26111-23 – Residential Wiring

3.1.2 Service Drop and Overhead Service Conductor
Clearances for Building Openings

NEC Section 230.9 states the
clearances required for service drop
conductors near building openings.

Module 26111-23 – Residential Wiring

3.2.0 Locating the Panelboard

•

The main service disconnect or
panelboard is usually located:
–

At the service entrance of a
residence
–

On an outside wall in an
unfinished basement or utility
room

•

An outdoor emergency disconnect
is also required on all one- and
two-family dwelling unit services.

Module 26111-23 – Residential Wiring

Trade Terms

Roughing in: The first stage of an electrical installation when you install the
raceway, cable, wires, boxes, and other equipment. You must complete the
roughing-in electrical work before you begin any finishing work.

Service-entrance equipment: Equipment that provides overcurrent
protection to the feeder and service conductors. It provides a means of
disconnecting the feeders from energized service conductors, and a means
of measuring the energy used.

Service point: The point of connection between the facilities of the serving
utility and the premises wiring.

Module 26111-23 – Residential Wiring

3.0.0 Section Review Question 1

1. According to NEC Section 230.24(B), if 120/240V service conductors
pass over residential property and driveways or commercial property that
is not subject to truck traffic where the voltage does not exceed 300V to
ground, the conductors must be at least _____.

a. 12' (3.7 m) above the ground

b. 15' (4.5 m) above the ground

c. 18' (5.5 m) above the ground

d. 20' (6 m) above the ground

Module 26111-23 – Residential Wiring

3.0.0 Section Review Question 1 Answer

1. According to NEC Section 230.24(B), if 120/240V service conductors
pass over residential property and driveways or commercial property that
is not subject to truck traffic where the voltage does not exceed 300V to
ground, the conductors must be at least _____.

a. 12' (3.7 m) above the ground

b. 15' (4.5 m) above the ground

c. 18' (5.5 m) above the ground

d. 20' (6 m) above the ground

Module 26111-23 – Residential Wiring

3.0.0 Section Review Question 2

2. According to NEC Section 230.70(A)(1), if you locate a means for
disconnecting service inside a building it must be _____.

a. as far as possible from the entrance of the service conductors

b. nearest the point of entrance of the service conductors

c. under the slab

d. in the utility room

Module 26111-23 – Residential Wiring

3.0.0 Section Review Question 2 Answer

2. According to NEC Section 230.70(A)(1), if you locate a means for
disconnecting service inside a building it must be _____.

a. as far as possible from the entrance of the service conductors

b. nearest the point of entrance of the service conductors

c. under the slab

d. in the utility room

Next…

4.0.0
Residential Wiring Methods

Read Sections 4.0.0 through 4.2.0. Complete the 4.0.0 Section
Review.

Electrical

Module 26111-23

Residential Wiring

Copyright © 2024 by NCCER, Alachua, FL 32615. Published by Pearson. All rights reserved.

4.0.0 Residential Wiring Methods

Module 26111-23 – Residential Wiring

Objective

4. Identify wiring methods for various types of residences.

a. Explain how to select and install cable systems.

b. Explain how to select and install raceways.

Module 26111-23 – Residential Wiring

Performance Tasks

There are no Performance Tasks associated with this section.

Module 26111-23 – Residential Wiring

4.0.0–4.1.0 Residential Wiring Methods

•

Open wiring systems are used when it will not affect the appearance of
the residence, such as in unfinished basements, attics, and garages.

•

Wiring systems are concealed in finished areas of the residence.

•

Two basic wiring methods:
–

Sheathed cables of two or more conductors
–

Raceway (conduit) systems

Module 26111-23 – Residential Wiring

4.1.1 Using Nonmetallic-Sheathed Cable

•

NEC Article 334 covers
requirements, installation, and
construction specifications for
nonmetallic-sheathed cable.

•

Type NMC is basically the same
as Type NM, except it has a
corrosion-resistant outer
nonmetallic sheath.

Module 26111-23 – Residential Wiring

4.1.2 Using Metal-Clad (MC) Cable

•

Metal-clad cable has one or
more insulated conductors in a
metallic sheath.

•

The metallic covering offers
greater mechanical protection
than Type NM cable.

Module 26111-23 – Residential Wiring

4.1.3 Using Underground Feeder Cable

NEC Article 340 covers underground feeder (Type UF) cable.
•

It can be buried directly in the earth.
•

If above ground and in the sun, the outer covering must be sunlight-
resistant.
•

It must be protected from damage where it emerges from the ground.

Module 26111-23 – Residential Wiring

4.1.4 Using Service-Entrance Cable

NEC Articles 230 and 338 specify how
you must install service-entrance (Type
SE) and underground service-entrance
(Type USE) cable for electrical services.

Module 26111-23 – Residential Wiring

4.2.0 Raceways

•

A raceway holds and protects wires, cables, or busbars.

•

Types of raceways include:
–

Rigid metal conduit
–

Intermediate metal conduit
–

Rigid nonmetallic conduit
–

Flexible metallic conduit
–

Electrical metallic tubing
–

Auxiliary gutters

•

Raceways are also bonded together to provide a continuous equipment
grounding system.

Module 26111-23 – Residential Wiring

Trade Terms

Metal-clad (Type MC) cable: A factory assembly of one or more insulated
circuit conductors with or without optical fiber members enclosed in an
armor of interlocking metal tape or a smooth or corrugated metallic sheath.

Nonmetallic-sheathed (Type NM and NMC) cable: A factory assembly of
two or more insulated conductors enclosed within an overall nonmetallic
jacket. Type NM contains insulated conductors enclosed within an overall
nonmetallic jacket. Type NMC contains insulated conductors enclosed within
an overall corrosion-resistant, nonmetallic jacket.

Romex®: General Cable’s trade name for Type NM cable; however, it is often
used generically to refer to any nonmetallic-sheathed cable.

Module 26111-23 – Residential Wiring

4.0.0 Section Review Question 1

1. In three-wire Type NM cable, the color code of the conductors is _____.

a. black, white, and red, with a bare or green grounding conductor

b. black, black, and white, with a bare or green grounding conductor

c. black, blue, and white, with a bare or green grounding conductor

d. black, black, and black, with a bare or green grounding conductor

Module 26111-23 – Residential Wiring

4.0.0 Section Review Question 1 Answer

1. In three-wire Type NM cable, the color code of the conductors is _____.

a. black, white, and red, with a bare or green grounding conductor

b. black, black, and white, with a bare or green grounding conductor

c. black, blue, and white, with a bare or green grounding conductor

d. black, black, and black, with a bare or green grounding conductor

Module 26111-23 – Residential Wiring

4.0.0 Section Review Question 2

2. Which of the following areas of a residence would most likely use
conductors run in conduit?

a. Bedrooms

b. Bathrooms

c. Kitchens

d. Unfinished basements

Module 26111-23 – Residential Wiring

4.0.0 Section Review Question 2 Answer

2. Which of the following areas of a residence would most likely use
conductors run in conduit?

a. Bedrooms

b. Bathrooms

c. Kitchens

d. Unfinished basements

Next…

5.0.0
Laying Out Branch Circuits and Sizing Outlet Boxes

Read Sections 5.0.0 through 5.3.2. Complete the 5.0.0 Section
Review.

Electrical

Module 26111-23

Residential Wiring

Copyright © 2024 by NCCER, Alachua, FL 32615. Published by Pearson. All rights reserved.

5.0.0 Laying Out Branch Circuits and Sizing Outlet
Boxes

Module 26111-23 – Residential Wiring

Objective

5. Explain how to lay out branch circuits and size outlet boxes.

a. Describe how to complete a branch circuit layout for power.

b. Describe how to complete a branch circuit layout for lighting.

c. Describe how to install outlet boxes.

Module 26111-23 – Residential Wiring

Performance Task

3. Select the proper type and size of outlet box needed for a given set of
wiring conditions

Module 26111-23 – Residential Wiring

5.0.0–5.1.0 Branch Circuit Layout for Power

•

An outlet is the point at
which electrical equipment,
appliance, and devices are
connected to the wiring
system.

•

Classifications of outlets:
–

Lighting
–

Receptacle
–

Motor
–

Appliance

Module 26111-23 – Residential Wiring

5.1.1 Branch Circuits and Feeders

•

Branch circuits run from the panelboard to the outlets.

•

The size of the branch circuit conductors depends on the load
requirements.

Module 26111-23 – Residential Wiring

5.1.2 Locating Receptacles

•

NEC Section 210.52 states
that no point along the floor
line of any wall space can be
more than 6' from an outlet.

•

GFCI protection is required
for all receptacles on kitchen
countertops or located within
a bathroom, garage, or on the
exterior.

Module 26111-23 – Residential Wiring

5.1.3 Using Split-Wired Duplex Receptacles

•

Split-wired duplex wall receptacles
allow one outlet to be controlled by
a wall switch and the other wired
as a standard outlet.

•

Or split-wired duplex receptacles
can have one outlet used to supply
240V for an appliance and the
other outlet to supply 120V for an
appliance.

Module 26111-23 – Residential Wiring

5.1.4 Identifying Multiwire Branch Circuits

NEC Section 210.4(B) requires the use of a two-pole breaker when two
circuits are connected to one duplex receptacle so that all ungrounded
conductors of the circuit are disconnected simultaneously.

Module 26111-23 – Residential Wiring

5.1.5 Installing 240V Circuits

Electric ranges, clothes dryers, and
water heaters operate at 240VAC.
•

Each must be fed by a
separate circuit and connected
to a two-pole circuit breaker.

Module 26111-23 – Residential Wiring

5.1.6 Laying Out Electric Heating Circuits

Electric baseboard heaters are
generally located on outside walls
near the areas of greatest heat loss.

Module 26111-23 – Residential Wiring

5.2.0 Branch Circuit Layout for Lighting

Make sure the circuits used to
feed residential lighting conform to
NEC® standards and local and
state ordinances.

Module 26111-23 – Residential Wiring

5.3.0 Sizing and Mounting Outlet Boxes

•

NEC Table 314.16(A) specifies
the maximum number of
conductors of the same size
permitted in standard outlet
boxes.

•

Fittings or devices, such as
fixture studs, cable clamps,
switches, or receptacles, reduce
the number of conductors that
are allowed.

Module 26111-23 – Residential Wiring

5.3.1 Mounting Outlet Boxes

•

Outlet boxes may be mounted
in a variety of ways.

•

Outlet boxes are mounted by
nailing them to wall studs.

•

NEC Section 314.20 specifies
the amount of space permitted
from the edge of the outlet box
to the finished wall.

Module 26111-23 – Residential Wiring

5.3.2 Ceiling-Suspended (Paddle) Fan Boxes

Ceiling-suspended fan outlet boxes are not permitted to be used as the sole
support for a ceiling-suspended fan unless the box is listed as such.
•

Boxes shall be marked with the maximum weight to be supported.
•

These boxes shall be rigidly supported by a structural member of the
building.

Module 26111-23 – Residential Wiring

Trade Term

Switch leg: A circuit routed to a switch box for controlling electric lights.

Module 26111-23 – Residential Wiring

5.0.0 Section Review Question 1

1. A branch circuit that supplies a storage-type water heater with a capacity
of 120 gallons (450 liters) or less and a nameplate rating of 20A must be
rated at a minimum of _____.

a. 18A

b. 20A

c. 22A

d. 25A

Module 26111-23 – Residential Wiring

5.0.0 Section Review Question 1 Answer

1. A branch circuit that supplies a storage-type water heater with a capacity
of 120 gallons (450 liters) or less and a nameplate rating of 20A must be
rated at a minimum of _____.

a. 18A

b. 20A

c. 22A

d. 25A

Module 26111-23 – Residential Wiring

5.0.0 Section Review Question 2

2. A branch circuit for lighting has a capacity of 1,800VA. It should be loaded
to no more than _____.

a. 1,440VA

b. 1,800VA

c. 2,250VA

d. 2,700VA

Module 26111-23 – Residential Wiring

5.0.0 Section Review Question 2 Answer

2. A branch circuit for lighting has a capacity of 1,800VA. It should be loaded
to no more than _____.

a. 1,440VA

b. 1,800VA

c. 2,250VA

d. 2,700VA

Module 26111-23 – Residential Wiring

5.0.0 Section Review Question 3

3. A metallic outlet box for two No. 12 AWG conductors with a ground wire,
cable clamp, a switch, and a looped conductor over 12" (300 mm) would
count as _____.

a. two conductors

b. four conductors

c. five conductors

d. eight conductors

Module 26111-23 – Residential Wiring

5.0.0 Section Review Question 3 Answer

3. A metallic outlet box for two No. 12 AWG conductors with a ground wire,
cable clamp, a switch, and a looped conductor over 12" (300 mm) would
count as _____.

a. two conductors

b. four conductors

c. five conductors

d. eight conductors

Next…

6.0.0
Wiring Devices

Read Sections 6.0.0 through 6.3.0. Complete the 6.0.0 Section
Review.

Electrical

Module 26111-23

Residential Wiring

Copyright © 2024 by NCCER, Alachua, FL 32615. Published by Pearson. All rights reserved.

6.0.0 Wiring Devices

Module 26111-23 – Residential Wiring

Objective

6. Explain how to select and install various wiring devices.

a. Describe how to select and install receptacles.

b. Describe how to select and install switches.

c. Describe how to install devices near residential swimming pools, spas,
and hot tubs.

Module 26111-23 – Residential Wiring

Performance Tasks

There are no Performance Tasks associated with this section.

Module 26111-23 – Residential Wiring

6.0.0–6.1.0 Working with Receptacles

•

The regulations for receptacles are
in NEC Article 406.

•

The terminals of receptacles are
color coded.

•

Receptacles must be imprinted with
several symbols indicating its rating
and that it meets safety
requirements.

Module 26111-23 – Residential Wiring

6.2.0 Lighting Control

•

NEC Article 404 covers
information pertaining to
switches.

•

The single-pole quiet switch is
the most common switch for
use in lighting applications.

Module 26111-23 – Residential Wiring

6.2.1 Three-Way Switches

•

Three-way switches control one or
more lamps from two different
locations.

•

They may be connected in several
different ways.

Module 26111-23 – Residential Wiring

6.2.2 Four-Way Switches

To control lighting from three or more
locations, you’ll need:
•

One or more four-way
switches
•

Two three-way switches

Module 26111-23 – Residential Wiring

6.2.3–6.2.4 Exploring Relays for Remote-Control Lighting

•

An electric relay is a device that uses an electric current to cause the
opening or closing of one or more pairs of contacts.

•

A popular use of electric relays is to provide remote-control lighting in
residential systems.

Module 26111-23 – Residential Wiring

6.2.5 Dimmers

•

Dimmers allow you to control the
brightness of a light.

•

Dimmers must be matched to the
wattage and type of application.

Module 26111-23 – Residential Wiring

6.2.6 Switch Locations

NEC Article 210 lists
requirements for light and
switch placement in a home.

Module 26111-23 – Residential Wiring

6.2.7 Low-Voltage Electrical Systems

•

Low-voltage systems can be used to
control lighting circuits.
–

Allows you to control lighting from
several different locations.

•

Low-voltage systems are preferred for
extensive or complex lighting control.

•

NEC Articles 724 and 725 cover the
installation of low-voltage system
wiring.

Module 26111-23 – Residential Wiring

6.3.0 Residential Swimming Pools, Spas, and Hot Tubs

NEC Article 680 provides rules
for electrical equipment and
wiring in or adjacent to locations
such as:
•

Swimming pools
•

Spas
•

Hot tubs
•

Fountains

Module 26111-23 – Residential Wiring

Trade Terms

There are no Trade Terms associated with this section.

Module 26111-23 – Residential Wiring

6.0.0 Section Review Question 1

1. The brass screw on a receptacle connects to the _____.

a. equipment grounding conductor

b. neutral conductor

c. grounded conductor

d. ungrounded conductor

Module 26111-23 – Residential Wiring

6.0.0 Section Review Question 1 Answer

1. The brass screw on a receptacle connects to the _____.

a. equipment grounding conductor

b. neutral conductor

c. grounded conductor

d. ungrounded conductor

Module 26111-23 – Residential Wiring

6.0.0 Section Review Question 2

2. The correct operation of a four-way switch requires _____.

a. one three-way switch

b. two three-way switches

c. three three-way switches

d. four three-way switches

Module 26111-23 – Residential Wiring

6.0.0 Section Review Question 2 Answer

2. The correct operation of a four-way switch requires _____.

a. one three-way switch

b. two three-way switches

c. three three-way switches

d. four three-way switches

Module 26111-23 – Residential Wiring

6.0.0 Section Review Question 3

3. The minimum distance between a receptacle and the inside wall of the hot
tub is _____.

a. 6' (1.8 m)

b. 10' (3 m)

c. 12' (3.7 m)

d. 15' (4.5 m)

Module 26111-23 – Residential Wiring

6.0.0 Section Review Question 3 Answer

3. The minimum distance between a receptacle and the inside wall of the hot
tub is _____.

a. 6' (1.8 m)

b. 10' (3 m)

c. 12' (3.7 m)

d. 15' (4.5 m)

Next…

Review for Module Testing

Complete the Review Questions at the end of the module and prepare
for the Module Test.