1. Daily Lesson Electrical Conductors Prepared by: Brian Alexander This lesson is from Virginia Tech and has not been edited by the Georgia Curriculum Office.

2. Electrical Conductors Performance Objectives: Student will be able to (SWBAT): 1. Describe the basic types of electrical conductors. 2. Explain how electrical conductors are classified. 3. Explain the purpose of wire insulation. 4. Describe electrical cables.

3. Electrical Conductors Enabling Objectives: SWBAT 1. Identify the different types of conductors. 2. Describe the pros and cons of different electrical conductors. 3. Explain how electrical conductors are sized.

4. Electrical Conductors Enabling Objectives: (Continued) 4. Describe color coding used in electrical wiring. 5. Describe the types of insulators used to cover electrical conductors. 6. Identify the types of electrical cable used in Agriculture and residential applications.

5. Electrical Conductor • Critical Thinking: • What is an Electrical Conductor? • Anything that transmits electricity.

6. Warning • Interest Approach: • Electricity is always looking for a conductor!

7. Common Electrical Conductors • Silver-- Best • Copper -- 2nd • Gold-- 3rd • Aluminum-- 4th • Tungsten-- Poor

8. Silver • Precious metal • High cost • Not practical for wire • Corrosive problems (such as silver 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.

9. Copper • Used in many wiring applications • Reasonable cost • Flexible • Easy to make into wire • Good corrosion resistance

10. Gold • Precious Metal • Very expensive • Does not corrode • Seldom used as a wire • Used to plate (coat) connectors in electronic devices

11. Aluminum • Abundant metal • Reasonable cost • Flexible • Light weight • Corrosion problems / reacts with other metals

12. Aluminum (continued) • Used in large wire sizes - power lines and service entrance cable • Electrical wire # 4 and larger is usually aluminum and stranded. • Pound for pound aluminum is a better conductor than copper.

13. Tungsten • Rare metal • Used to make light-bulb filaments • High melting point • Poor conductor • Electrodes for TIG Welding

14. Electrical Wire Size • the larger the wire, the more electricity it can carry • wire size is expressed by numbers from the American Wire Gauge system (AWG) • the larger the wire size, the smaller the AWG number

15. Wire Size Chart

16. Wire Sizing • Sizing conductors according to load • Need to know the desired voltage drop • Need to know the load in amps on the circuit • Need to know the length of circuit in feet • Need to know the Voltage of the circuit • Use the wire sizing tables to determine what size conductor to use.

17. Wire Identification (examples) • 12/3 G or 12-3 w/G • 12 is the gauge of the conductor wire • 3 is the number of conductors • G or w/G means there is a safety ground wire also

18. Color Code for Wires • Individual wires are color coded to identify their function.

19. Wire Color Code Chart

20. Wire Insulation • Prevents electricity from jumping from one conductor to another (prevents short circuits) • Most wires are insulated with plastic vinyl • Individual wires have color coded insulation

21. Types of Insulation • R Rubber Insulation • RH Heat Resistant Rubber • RW Moisture Resistant Rubber • Ru Latex Rubber • RuA Latex Rubber with Asbestos sub.

22. Electrical Cables • A group of two or more wires enclosed in a metal, rubber, or plastic sheath is called a cable. • The sheath protects the wire from damage. • Metal conduit also protects wires, but is not considered a cable.

23. Common Types of Cables

24. Electrical Conductors Summary • Many materials have the ability to conduct electricity. • Wire size is important for proper and safe electrical conduction. • The color code on wires is used to identify the wire’s purpose.

25. Electrical Conductors • The insulation on a wire prevents electricity from jumping from one conductor to another. • Electrical cables are use extensively in agricultural, industrial, business and residential applications.