Maricopa Community Colleges  ABC225   19956-20046 
Official Course Description: MCCCD Approval: 04/25/95
ABC225 19956-20046 LEC 2 Credit(s) 2 Period(s)
Overcurrent Protection & Conductors
Understanding, defining and using overcurrent protection including: terminology, safety factors, conformance to National Electrical Code, fuses, circuit breakers, short circuits, selection and sizing of overcurrent protection. Proper selection and calculation of conductors including an understanding of National Electrical Code requirements and conductor types and purposes. Prerequisites: (Indentured status with the Arizona Builders Alliance and ABC132) or permission of the apprenticeship coordinator.
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MCCCD Official Course Competencies:
 
ABC225   19956-20046 Overcurrent Protection & Conductors
1. Identify and define specific electrical terminology associated with overcurrent protection. (I)
2. Explain the importance of overcurrent protection as it relates to life safety and to protection of systems and equipment. (I)
3. Explain the function of fuses in overcurrent protection and describe specific types and uses of fuses. (II, III, IV)
4. Calculate "peak and RMS" values for specific current limiting devices and size conductors for specific loads. (IV)
5. Explain the use of single element and dual element fuses in motor overload and short-circuit protection. (V)
6. Describe the operation and specific uses of circuit breakers. (VI)
7. Select and size overcurrent protection for specific applications. (VII)
8. Define terminology related to electrical conductors and select conductors for specific applications. (VIII, IX)
9. Interpret and apply specific National Electrical Code (NEC) regulations governing conductors including: NEC parallel rules, NEC tap rules and NEC tables 310-16 through 310-19. (IX)
10. Describe specific properties of conductors by using NEC tables and identifying conductors through color coding. (X)
11. Calculate voltage drop in "single" and "three phase" applications. (XI)
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MCCCD Official Course Outline:
 
ABC225   19956-20046 Overcurrent Protection & Conductors
    I. Overcurrent Protection
        A. Terms and definitions
          1. Ampere rating
          2. Arcing time
          3. Current limitation
          4. High-speed fuses
          5. Interrupting capacity
          6. Melting time
          7. Overload
          8. Peak let-through current
          9. Resistive load
          10. Short circuit
          11. Voltage rating
          12. Other
        B. Overcurrents
        C. Overloads
        D. Short circuits
          1. Current at fault levels
          2. Current at operating levels
          3. Interrupting rating
      II. Fuseology
          A. Voltage rating
          B. Ampere rating
          C. Interrupting-rating safe operation
          D. Selective coordination
          E. Current limitation
        III. Operating Principles of Fuses
            A. Non-time delay fuses
            B. Dual-element time delay fuses
          IV. United Laboratories (UL) Fuse Classes
              A. Types of fuses
                1. Class "R"
                2. Class "CC"
                3. Class "G"
                4. Class "H"
                5. Class "J"
                6. Class "K"
                7. Class "L"
                8. Class "T"
              B. Branch circuit listed fuses
              C. Medium-voltage fuses
                1. General purpose current-limiting
                2. Back-up current-limiting
                3. Expulsion
              D. Application of medium-voltage fuses
                1. Voltage
                2. Continuous current-carrying capacity
                3. Interrupt rating
              E. Current limiting fuses
              F. Fuses for selective coordination
              G. Fuse time-current curves
              H. Peak let-through charts
            V. Motor Overload and Short-Circuit Protection
                A. Single element fuse
                B. Dual-element fuse
              VI. Circuit Breakers
                  A. Component parts
                  B. Interrupting capacity rating
                VII. Conductor Protection
                    A. National Electrical Code Sections
                    B. Fuse location in circuits - exceptions
                      1. No 1
                      2. No 2
                      3. No 3
                      4. No 4
                      5. No 5
                      6. No 6
                      7. No 7
                      8. No 8
                      9. No 9
                      10. No 10
                      11. No 11
                    C. Lighting/appliance loads
                    D. Feeder circuits with no motor load
                    E. Service equipment
                    F. Transformer secondary conductors
                    G. Motor circuit protection
                      1. Overload protection
                      2. Short-circuit protection
                      3. NEC regulations
                  VIII. Electrical Conductors
                      A. Terms and definitions
                        1. AWG (American Wire Gauge)
                        2. Cable
                        3. Cable, coaxial
                        4. Cable, duplex
                        5. Cable, service drop
                        6. Cable, tray
                        7. Cable, triplexed
                        8. Cable, vertical riser
                        9. Other
                      B. Characteristics
                        1. Method of stranding
                        2. Degree of hardness
                        3. Bare, tinned, or coated
                        4. Size
                      C. Compressed conductors
                    IX. Conductor Applications
                        A. National Electrical Code regulations
                        B. Feeder circuits
                        C. Branch circuits
                        D. Conductor protection
                        E. Locations of fuses in circuits
                      X. Properties of Conductors
                          A. Reading NEC tables
                          B. Identifying conductors
                            1. Color coding
                            2. Changing colors
                        XI. Voltage Drop
                            A. Wire sizes based on resistance
                            B. Circular mil-unit of conductor area
                            C. Conversion of square mils to circular mils
                            D. Resistance of conductors
                            E. Resistance of copper per mil foot
                            F. Equations for conductor area
                            G. Voltage drop equations
                            H. Miscellaneous voltage-drop equations
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