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Over-Current Protection

SKET 138

Over-Current Protection

SKET 138

Course Description

Prerequisite: SKET 120 with a minimum grade of "C". This course covers the requirements for adequate protection of wiring and equipment. Disconnects and circuit breakers are explained and calculations are made to determine sizing requirements. Fuse types and characteristics are discussed and calculations are made to determine appropriate fuse sizing to protect wiring. Short circuit interrupt rating is introduced and appropriate fuse types are selected for various applications. (30-0)

Outcomes and Objectives

Explain the theory of operation of over-current protection.

Objectives:

  • Describe the basic operation of a disconnect switch.
  • Explain the basic operation of a circuit breaker.
  • Describe the basic operation of a fuse.
  • Identify the primary components in disconnect switches, circuit breakers, and fuses.
  • Explain short circuit interrupt rating for interrupting devices.
  • Explain the basic operation and requirements for breaker boxes in residential applications.
  • Identify the primary components of an electrical breaker box.
  • Explain the use, operation, and proper wiring procedure for Ground Fault Circuit Interrupters (GFCI).

Apply the knowledge of over-current protection to perform calculations.

Objectives:

  • Perform calculations to determine the proper sizing of a disconnect switch for a given load.
  • Perform calculations to determine the proper sizing of a circuit breaker for a given load.
  • Perform calculations to determine the proper sizing of a fuse for a given load.
  • Perform calculations based on short circuit interrupt rating and select an appropriate device for a given application.
  • Differentiate between different fuse types and select an appropriate device for a given application.
  • Develop circuit diagrams for interrupting devices used in industrial applications.
  • Develop circuit diagrams for interrupting devices used in residential applications.

Apply knowledge of over-current protection to NEC and NFPA requirements.

Objectives:

  • State and comprehend safety precautions when working on electrical equipment.
  • Identify and explain requirements for industrial over-current protection based on applicable standards.
  • Identify and explain requirements for residential over-current protection based on applicable standards.
  • Develop troubleshooting techniques.