Daily LessonDaily Lesson

Electrical ConductorsElectrical Conductors

Prepared by:Prepared by:

Brian AlexanderBrian AlexanderThis lesson is from Virginia Tech and has not been edited by This lesson is from Virginia Tech and has not been edited by

the Georgia Curriculum Office.the Georgia Curriculum Office.

Electrical ConductorsElectrical Conductors

Performance Objectives:Performance Objectives:Student will be able to (SWBAT):Student will be able to (SWBAT):1. Describe the basic types of electrical 1. Describe the basic types of electrical

conductors.conductors.2. Explain how electrical conductors are 2. Explain how electrical conductors are

classified.classified.3. Explain the purpose of wire insulation.3. Explain the purpose of wire insulation.4. Describe electrical cables. 4. Describe electrical cables.

Electrical ConductorsElectrical Conductors

Enabling Objectives: Enabling Objectives:

SWBATSWBAT

1. Identify the different types of 1. Identify the different types of conductors.conductors.

2. Describe the pros and cons of different 2. Describe the pros and cons of different electrical conductors.electrical conductors.

3. Explain how electrical conductors are 3. Explain how electrical conductors are sized.sized.

Electrical ConductorsElectrical Conductors

Enabling Objectives: (Continued)Enabling Objectives: (Continued)

4. Describe color coding used in electrical 4. Describe color coding used in electrical wiring.wiring.

5. Describe the types of insulators used to 5. Describe the types of insulators used to cover electrical conductors.cover electrical conductors.

6. Identify the types of electrical cable 6. Identify the types of electrical cable used in Agriculture and residential used in Agriculture and residential applications.applications.

Electrical ConductorElectrical Conductor

Critical Thinking:Critical Thinking: What is an Electrical What is an Electrical

Conductor?Conductor? Anything that Anything that

transmits electricity.transmits electricity.

Warning Warning

Interest Approach:Interest Approach: Electricity is always Electricity is always

looking for a looking for a conductor! conductor!

Common Electrical ConductorsCommon Electrical Conductors

Silver-- BestSilver-- Best Copper -- 2ndCopper -- 2nd Gold-- 3rdGold-- 3rd Aluminum-- 4thAluminum-- 4th Tungsten-- PoorTungsten-- Poor

SilverSilver

Precious metal Precious metal High costHigh cost Not practical for wire Not practical for wire Corrosive problems Corrosive problems

(such as silver (such as silver tarnishes)tarnishes) The Silver Nugget which was

reputedly the largest silver nugget ever mined came out in three pieces from the Smuggler or the Molly Gibson mines—ironically after silver prices had crashed in 1893.

CopperCopper

Used in many wiring Used in many wiring applicationsapplications

Reasonable costReasonable cost FlexibleFlexible Easy to make into Easy to make into

wirewire Good corrosion Good corrosion

resistance resistance

GoldGold

Precious MetalPrecious Metal Very expensiveVery expensive Does not corrodeDoes not corrode Seldom used as a Seldom used as a

wirewire Used to plate (coat) Used to plate (coat)

connectors in connectors in electronic deviceselectronic devices

AluminumAluminum

Abundant metalAbundant metal Reasonable costReasonable cost FlexibleFlexible Light weightLight weight Corrosion Corrosion

problems / reacts problems / reacts with other metalswith other metals

Aluminum Aluminum (continued)(continued)

Used in large wire sizes - power lines Used in large wire sizes - power lines and service entrance cableand service entrance cable

Electrical wire # 4 and larger is usually Electrical wire # 4 and larger is usually aluminum and stranded.aluminum and stranded.

Pound for pound aluminum is a better Pound for pound aluminum is a better conductor than copper.conductor than copper.

TungstenTungsten

Rare metalRare metal Used to make light-Used to make light-

bulb filamentsbulb filaments High melting pointHigh melting point Poor conductorPoor conductor Electrodes for TIG Electrodes for TIG

Welding Welding

Electrical Wire SizeElectrical Wire Size

the larger the wire, the more electricity it the larger the wire, the more electricity it can carrycan carry

wire size is expressed by numbers from wire size is expressed by numbers from the American Wire Gauge system the American Wire Gauge system (AWG) (AWG)

the larger the wire size, the smaller the the larger the wire size, the smaller the AWG numberAWG number

Wire Size Chart Wire Size Chart

Wire SizingWire Sizing

Sizing conductors according to loadSizing conductors according to load Need to know the desired voltage dropNeed to know the desired voltage drop Need to know the load in amps on the Need to know the load in amps on the

circuitcircuit Need to know the length of circuit in feetNeed to know the length of circuit in feet Need to know the Need to know the VoltageVoltage of the circuit of the circuit Use the wire sizing tables to determine Use the wire sizing tables to determine

what size conductor to use.what size conductor to use.

Wire Identification (examples)Wire Identification (examples)

12/3 G or 12-3 w/G12/3 G or 12-3 w/G 12 is the gauge of the conductor wire12 is the gauge of the conductor wire 3 is the number of conductors3 is the number of conductors G or w/G means there is a safety G or w/G means there is a safety

ground wire alsoground wire also

Color Code for WiresColor Code for Wires

Individual wires are color coded to Individual wires are color coded to identify their function.identify their function.

Wire Color Code Chart Wire Color Code Chart

Wire InsulationWire Insulation

Prevents electricity from jumping from Prevents electricity from jumping from one conductor to another (prevents one conductor to another (prevents short circuits)short circuits)

Most wires are insulated with plastic Most wires are insulated with plastic vinylvinyl

Individual wires have color coded Individual wires have color coded insulationinsulation

Types of InsulationTypes of Insulation

RR Rubber InsulationRubber Insulation RHRH Heat Resistant RubberHeat Resistant Rubber RW RW Moisture Resistant RubberMoisture Resistant Rubber RuRu Latex RubberLatex Rubber RuARuA Latex Rubber with AsbestosLatex Rubber with Asbestos

sub.sub.

Electrical CablesElectrical Cables

A group of two or more wires enclosed A group of two or more wires enclosed in a metal, rubber, or plastic sheath is in a metal, rubber, or plastic sheath is called a cable.called a cable.

The sheath protects the wire from The sheath protects the wire from damage.damage.

Metal conduit also protects wires, but is Metal conduit also protects wires, but is not considered a cable.not considered a cable.

Common Types of CablesCommon Types of Cables

Electrical ConductorsElectrical Conductors

SummarySummary Many materials have the ability to Many materials have the ability to

conduct electricity.conduct electricity. Wire size is important for proper and Wire size is important for proper and

safe electrical conduction.safe electrical conduction. The color code on wires is used to The color code on wires is used to

identify the wire’s purpose.identify the wire’s purpose.

Electrical ConductorsElectrical Conductors

The insulation on a wire prevents The insulation on a wire prevents electricity from jumping from one electricity from jumping from one conductor to another.conductor to another.

Electrical cables are use extensively in Electrical cables are use extensively in agricultural, industrial, business and agricultural, industrial, business and residential applications.residential applications.