Maricopa Community Colleges  ABA203   19974-20032 
Official Course Description: MCCCD Approval: 03/25/97
ABA203 19974-20032 LEC 1 Credit(s) 1 Period(s)
Load Calculations - Branch Circuits
Load calculations for single-phase and three-phase branch circuits. Sizing branch circuit overcurrent protection devices. Derating factors and calculating ampacity for single-phase and three-phase loads. Use of National Electrical Code (NEC) to calculate residential loads. Selecting branch circuit conductors and overcurrent protection devices for electric heat, air conditioning equipment, motors and welders. Prerequisites: (Indentured status with the Arizona Builders Alliance) or permission of the apprenticeship coordinator.
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MCCCD Official Course Competencies:
 
ABA203   19974-20032 Load Calculations - Branch Circuits
1. Define trade terms associated with electrical load calculations. (I)
2. Calculate loads for single-phase and three-phase branch circuits. (II)
3. Size branch circuit overcurrent protection devices for non- continuous and continuous duty circuits. (III)
4. Explain how to apply derating factors to the sizing of branch circuits. (IV)
5. Calculate ampacity for single-phase and three-phase loads, and use load calculations to determine branch circuit conductor sizes. (V)
6. Use NEC Tables to calculate residential equipment loads. (VI)
7. Select branch circuit conductors and overcurrent protection devices for electric heat, air conditioning equipment, motors and welders. (VII)
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MCCCD Official Course Outline:
 
ABA203   19974-20032 Load Calculations - Branch Circuits
    I. Terminology
        A. Ampacity
        B. Branch circuit
        C. Continuous load
        D. Demand factor
        E. Multi-wire branch circuit
        F. Nominal voltage
        G. Overcurrent
        H. Receptacle
        I. Utilization equipment
        J. Voltage to ground
        K. Other
      II. Load Calculations - Single and Three-Phase Circuits
          A. Maximum load
          B. Non-continuous load
          C. Continuous load
          D. Circuit capacity
        III. Sizing Overcurrent Protection Devices
            A. Non-continuous load
            B. Continuous load
          IV. Derating Factors - NEC
              A. Continuous duty load
              B. Conductors per raceway
              C. High ambient temperature
              D. Excessive voltage drop
            V. Ampacity
                A. Single-phase circuits
                B. Three-phase circuits
                C. Conductor requirements - NEC
              VI. Residential Loads - NEC
                  A. Small appliances
                    1. NEC 210-52(b)
                    2. NEC 220-4(b)
                    3. NEC 220-16(a)
                  B. Laundry circuit
                    1. NEC 210-52(f)
                    2. NEC 220-4(c)
                    3. NEC 220-16(b)
                  C. Dryers - NEC 220-18
                  D. Cooking appliances - NEC 220-19
                  E. Water heaters - NEC 422-14(b)
                VII. Conductors and Circuit Breakers
                    A. Electric heating loads - NEC 424
                    B. Air conditioning loads
                      1. NEC 440-32
                      2. NEC 440-22(a)
                      3. NEC 310-16
                    C. Motor loads
                      1. NEC 430-148 single phase
                      2. NEC 430-150 three phase
                    D. Welders - NEC 630
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