NCCER Module 26109-23 PT9

Electrical

Module 26109-23

Conductors and Cables

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

1.0.0 Conductors

Module 26109-23 – Conductors and Cables

Objective

1. Classify conductors by wire size, insulation, and application.

a. Identify wire sizes.

b. Determine conductor ampacities.

c. Identify conductor materials.

d. Identify conductor insulation.

e. Identify fixture wiring.

f.

Identify cable types and applications.

g. Identify instrumentation control wiring.

Module 26109-23 – Conductors and Cables

Performance Tasks

There are no Performance Tasks associated with this section.

Module 26109-23 – Conductors and Cables

1.0.0–1.1.0 Wire Sizes

•

The term conductor has two meanings:
–

The current-carrying portion of a wire or cable
–

A wire or cable made of the current-carrying part and the outer
covering or insulator

•

Conductor size refers to the cross-sectional area of the current-carrying
portion of the wire.
–

Wire sizes are expressed in gauge numbers.
–

The US uses the American Wire Gauge (AWG) system.

Module 26109-23 – Conductors and Cables

1.1.1 AWG System

•

Common AWG sizes range from
40 (smallest) to 4/0 (largest).

•

NEC Chapter 9, Table 8,
Conductor Properties, has
information on wire sizes,
stranding, and the DC resistance.

Module 26109-23 – Conductors and Cables

1.1.2 Stranding

•

Stranded conductors are made from multiple
wires bunched together.
–

Stranded wire is more flexible and easier to
work with.

•

According to NEC Chapter 9, Table 8:
–

Wire sizes No. 18 to No. 2 have 7 strands.
–

Wire sizes No. 1 to No. 4/0 have 19 strands.
–

Wire sizes between 250 kcmil and 500 kcmil
have 37 strands.

Module 26109-23 – Conductors and Cables

1.1.3 Circular Mils

•

A circular mil is a circle that has a
diameter of 1 mil, which is 0.001".

•

It’s much easier to express the cross-
sectional area of a wire in circular mils
(or thousands of circular mils) than in
square inches.

Module 26109-23 – Conductors and Cables

1.2.0 Conductor Ampacities

•

A conductor’s ampacity is affected by:
–

Conductor material and size
–

Insulation
–

Installation location

•

NEC Tables 310.16 through 310.21 list the maximum ampacity of
conductors for given conditions.
–

It is important to select the right type of insulation to be used.

Module 26109-23 – Conductors and Cables

1.3.0–1.3.3 Conductor Materials

•

Copper is the most common conductor material.

•

Material used for wire is determined by:
–

Conductivity: the ease with which an electric current travels through a
conductor
–

Cost: a lower-cost conductor may be a better choice but often
depends upon availability
–

Workability: how easy it is to work with a conductor

Module 26109-23 – Conductors and Cables

1.4.0 Conductor Insulation

Early electrical distribution systems
used the knob-and-tube method to
install wire.

Module 26109-23 – Conductors and Cables

1.4.1 Types of Insulation for 600V to 1,000V Conductors

NEC Table 310.4(1) lists the application and construction data for 600V
insulated conductors.
•

There are many types of 600V insulated conductors, each with a
different letter designation.

Module 26109-23 – Conductors and Cables

1.4.2–1.4.3 Thermoset Insulation

•

There are many types of thermoplastic insulation, including:
–

Polyvinyl chloride (PVC)
–

Polyethylene (PE)
–

Cross-linked polyethylene (XLP)
–

Nylon
–

Teflon®

•

Thermoset insulations include RHH, RHW, XHH, XHHW, and SIS.
–

They maintain their form when heated.

Module 26109-23 – Conductors and Cables

1.4.4–1.4.5 Color Coding

•

Conductor insulation for building
wire is letter coded, which
indicates the type of insulation or
its environmental rating.

•

A color code is also used to help
electricians identify wire.
–

There is no standard color
code.
–

Protect yourself by testing
circuits with a voltmeter.

Module 26109-23 – Conductors and Cables

1.4.6 Wire Ratings

•

Wire ratings include the temperature rating.
–

It bases the allowed ampacity on the ambient temperature plus the
heat produced by the conductor.

•

If the ambient temperature is over 86°F (30°C), the conductor’s maximum
load-current rating must be reduced proportionally.

Module 26109-23 – Conductors and Cables

1.5.0 Fixture Wiring

•

Fixture wire is used for interior
wiring of fixtures and for wiring
fixtures to a power source.

•

The type of fixture wire selected
depends on the fixture’s operating
temperature so it will have the
correct insulation.

Module 26109-23 – Conductors and Cables

1.6.0 Cable Types and Applications

•

Cables are two or more insulated
wires covered by an outer jacket or
sheath and may contain a grounding
wire.

•

Cables are classified by:
–

Type of covering it has
–

Where it can be used
–

Exposure to sunlight
–

Rough use

Module 26109-23 – Conductors and Cables

1.6.1 Nonmetallic-Sheathed Cable

•

Nonmetallic-sheathed cable is
used for branch circuits and
feeders.
–

Two or more insulated
conductors and one bare
conductor enclosed in a
nonmetallic sheath

•

NEC Article 334 specifies the
many requirements for Type NM
and NMC cables.

Module 26109-23 – Conductors and Cables

1.6.2 Underground Feeder and Branch Circuit Cable

NEC Article 340 specifies where and
when to use underground feeder and
branch circuit (Type UF) cable.

Module 26109-23 – Conductors and Cables

1.6.3 Medium-Voltage Cable

NEC Article 315 covers the use of
medium-voltage (Type MV) cable.
•

Suitable for voltages from
2,001V to 35,000V
•

Wet or dry locations
•

May be buried directly

Module 26109-23 – Conductors and Cables

1.6.4 Metal-Clad Cable

•

NEC Article 330 covers metal-clad
(Type MC) cable.
–

Can be used in a wide variety of
applications.

•

It may or may not have an outer jacket.

•

There are three types of MC cable:
–

Smooth metallic sheath
–

Corrugated metallic sheath
–

Interlocking metal tape armor

•

NEC Article 330.10 specifies the usage
of MC cable.

Module 26109-23 – Conductors and Cables

1.6.5 High-Voltage Shielded Cable

Shielding is added to high-voltage cables for protection.

Module 26109-23 – Conductors and Cables

1.6.6 Channel Wire Assemblies

•

Channel wire assemblies include:
–

The cable
–

Cable supports
–

Splicers
–

Circuit taps
–

Fixture hangers
–

Fittings

•

Flat cable assemblies (Type FC) are
suitable for branch circuits that supply
small appliances or small power loads.

Module 26109-23 – Conductors and Cables

1.6.7 Flat Conductor Cable

•

NEC Article 324 covers the use of flat conductor cable (Type FCC).

•

Type FCC cable has three to five flat conductors, placed edge to edge,
and enclosed in an assembly.

•

Type FCC is meant to be run under carpets.

Module 26109-23 – Conductors and Cables

1.6.8 Power and Control Tray Cable

NEC Article 336 specifies guidelines
for using power and control tray
cable (Type TC).
•

Can be used in cable trays and
raceways
•

May be buried directly
•

Can be good for use in
sunlight

Module 26109-23 – Conductors and Cables

1.6.9 SE and USE Cable

NEC Article 338 covers the use of:
•

Service-entrance cable (Type
SE)
•

Underground service-entrance
cable (Type USE)

Module 26109-23 – Conductors and Cables

1.7.0 Instrumentation Control Wiring

•

Instrumentation control wiring
usually has two or more insulated
conductor wires protected by an
outer jacket.
–

There may also be a shield and
a drain wire.

•

NEC Articles 722, 724, and 725
provide information on the
application of instrumentation
control wiring.

Module 26109-23 – Conductors and Cables

1.7.1–1.7.3 Jackets

•

Shields are used to protect
electrical signals in the conductors.
–

Usually made of aluminum foil
bonded to a plastic film

•

A shield drain wire allows for the
connection of all the instruments to
a common grounding point.

•

PE and PVC jackets are the most
common.

Module 26109-23 – Conductors and Cables

Trade Terms

Ampacity: The maximum current in amperes a conductor can carry
continuously under the conditions of use without exceeding its temperature
rating.

Fish tape: A hand device used to pull a wire through a conduit run.

Module 26109-23 – Conductors and Cables

1.0.0 Section Review Question 1

1. According to NEC Chapter 9, Table 8, No. 3/0 AWG wiring has _____.

a. 3 strands

b. 7 strands

c. 19 strands

d. 37 strands

Module 26109-23 – Conductors and Cables

1.0.0 Section Review Question 1 Answer

1. According to NEC Chapter 9, Table 8, No. 3/0 AWG wiring has _____.

a. 3 strands

b. 7 strands

c. 19 strands

d. 37 strands

Module 26109-23 – Conductors and Cables

1.0.0 Section Review Question 2

2. Using NEC Table 310.16, the ampacity of a No. 6 AWG Type UF copper
cable is _____.

a. 40A

b. 55A

c. 65A

d. 75A

Module 26109-23 – Conductors and Cables

1.0.0 Section Review Question 2 Answer

2. Using NEC Table 310.16, the ampacity of a No. 6 AWG Type UF copper
cable is _____.

a. 40A

b. 55A

c. 65A

d. 75A

Module 26109-23 – Conductors and Cables

1.0.0 Section Review Question 3

3. If a conductor has a low resistance, it _____.

a. will conduct poorly

b. cannot be used in service-entrance cable

c. has a high conductivity

d. is suitable only for use in low-temperature applications

Module 26109-23 – Conductors and Cables

1.0.0 Section Review Question 3 Answer

3. If a conductor has a low resistance, it _____.

a. will conduct poorly

b. cannot be used in service-entrance cable

c. has a high conductivity

d. is suitable only for use in low-temperature applications

Module 26109-23 – Conductors and Cables

1.0.0 Section Review Question 4

4. Telephone wiring in a plenum space is likely to use _____.

a. Teflon® insulation

b. PVC insulation

c. PE insulation

d. XLP insulation

Module 26109-23 – Conductors and Cables

1.0.0 Section Review Question 4 Answer

4. Telephone wiring in a plenum space is likely to use _____.

a. Teflon® insulation

b. PVC insulation

c. PE insulation

d. XLP insulation

Module 26109-23 – Conductors and Cables

1.0.0 Section Review Question 5

5. Using NEC Table 402.5, the allowable ampacity of No. 14 AWG fixture
wire is _____.

a. 6A

b. 8A

c. 17A

d. 23A

Module 26109-23 – Conductors and Cables

1.0.0 Section Review Question 5 Answer

5. Using NEC Table 402.5, the allowable ampacity of No. 14 AWG fixture
wire is _____.

a. 6A

b. 8A

c. 17A

d. 23A

Module 26109-23 – Conductors and Cables

1.0.0 Section Review Question 6

6. What is the temperature rating of service-entrance cable when the cable is
not marked?

a. 77°F (25°C)

b. 104°F (40°C)

c. 131°F (55°C)

d. 167°F (75°C)

Module 26109-23 – Conductors and Cables

1.0.0 Section Review Question 6 Answer

6. What is the temperature rating of service-entrance cable when the cable is
not marked?

a. 77°F (25°C)

b. 104°F (40°C)

c. 131°F (55°C)

d. 167°F (75°C)

Module 26109-23 – Conductors and Cables

1.0.0 Section Review Question 7

7. Which of the following is the most common type of jacket?

a. PE

b. Rubber

c. Fiberglass

d. Silicone

Module 26109-23 – Conductors and Cables

1.0.0 Section Review Question 7 Answer

7. Which of the following is the most common type of jacket?

a. PE

b. Rubber

c. Fiberglass

d. Silicone

Next…

2.0.0
Installing Conductors in Conduit Systems

Read Sections 2.0.0 through 2.2.2. Complete the 2.0.0 Section
Review.

Electrical

Module 26109-23

Conductors and Cables

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

2.0.0 Installing Conductors in Conduit Systems

Module 26109-23 – Conductors and Cables

Objective

2. Explain how to install conductors in a conduit system.

a. Describe how to install conductors using fish tape.

b. Describe how to install conductors using pulling equipment.

Module 26109-23 – Conductors and Cables

Performance Task

1. Install conductors in a raceway system.

Module 26109-23 – Conductors and Cables

2.0.0–2.1.0 Fish Tape

•

Conductors are installed in
conduit by pulling them through.

•

Fish tape is fed through the
conduit.

•

Once it reaches the other end,
conductors are attached to the
hook.

•

The fish tape is reeled back
through, pulling the conductors
with it.

Module 26109-23 – Conductors and Cables

2.1.1 Power Conduit Fishing Systems

•

String lines are installed using a
power system.

•

String lines are attached to a mouse
(a foam plug).

•

Vacuum suction will push or pull the
plug through the conduit.

•

Once it reaches the other end,
conductors are attached to the string
and pulled back through the conduit.

Module 26109-23 – Conductors and Cables

2.1.2–2.1.3 Pull Lines

•

Often, more than one conductor is
fed through the conduit during a
wire pull.

•

Reel carts help keep wires from
tangling.

Module 26109-23 – Conductors and Cables

2.1.4 Safety Precautions

Some important safety precautions to follow while pulling cable:
•

Never use fish tape near live circuits.
•

Use mechanical lifts to move larger spools of cable.
•

Avoid pinch points in the capstans and sheaves.
•

Select a rope with a pulling load rating greater than needed.
•

Use only low-stretch rope.
•

Do not stand in a direct line with the pulling rope.
•

Keep the pulled rope out of the way.
•

Wrap up the pulling rope when done.

Module 26109-23 – Conductors and Cables

2.2.0–2.2.1 Conductor Lubrication

•

A manually operated puller is good
for smaller pulling jobs.

•

An electrical or hydraulic power
puller is used for longer runs or
those with several bends or large
conductors.

•

For long runs with several bends,
the conduit and wires are lubricated.

Module 26109-23 – Conductors and Cables

2.2.2 Conductor Termination

NEC Section 300.14 specifies the length of the free conductor at each
junction or outlet box.
•

Enough slack is needed for future splices.

Module 26109-23 – Conductors and Cables

Trade Terms

Capstans: The turning drums of the cable puller on which the rope is
wrapped and pulled.

Mouse: A cylinder of foam rubber that fits inside the conduit and is then
propelled by compressed air or vacuumed through the conduit run, pulling a
line or tape.

Wire grip: A device used to link pulling rope to cable during a pull.

Module 26109-23 – Conductors and Cables

2.0.0 Section Review Question 1

1. Which of the following is true when pulling conductors?

a. Pull lines are typically made of natural cotton.

b. Rodders can only be used in very short runs.

c. In multiconductor installations, always pull conductors one at a time.

d. If a pull is expected to be difficult, a pull line should be used rather
than a fish tape.

Module 26109-23 – Conductors and Cables

2.0.0 Section Review Question 1 Answer

1. Which of the following is true when pulling conductors?

a. Pull lines are typically made of natural cotton.

b. Rodders can only be used in very short runs.

c. In multiconductor installations, always pull conductors one at a time.

d. If a pull is expected to be difficult, a pull line should be used rather
than a fish tape.

Module 26109-23 – Conductors and Cables

2.0.0 Section Review Question 2

2. Large conductors are likely to require the use of _____.

a. electrically driven power pullers

b. hand pulling for additional precision

c. two or more power pullers

d. multiple stops during the pulling operation

Module 26109-23 – Conductors and Cables

2.0.0 Section Review Question 2 Answer

2. Large conductors are likely to require the use of _____.

a. electrically driven power pullers

b. hand pulling for additional precision

c. two or more power pullers

d. multiple stops during the pulling operation

Next…

Review for Module Testing

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