Understanding Electrical Faults and Fault Currents - e-learning on ACE: Electrical.

Electrical faults can pose significant risks, making it essential to understand how different types of fault currents behave and how they are managed in circuit design. Our Protection for Safety Pathway includes four modules that guide you through key concepts, from identifying faults to ensuring circuits disconnect safely.

Below is the recommended viewing order for these modules:

1. Faults and Currents – Types of Current

This module introduces the different types of electrical faults and explains key fault currents, including short-circuit currents and earth fault currents. It also explores common terminology and provides an overview of protective devices designed to mitigate these faults.

2. Faults and Currents – Time and Currents

Here, we examine the relationship between fault currents and disconnection times, highlighting the importance of Earth Fault Loop Impedance (Zs) in circuit design. The module explains how Zs influences the operation of overcurrent protective devices to ensure timely circuit disconnection during a fault.

3. Faults and Currents – Earth Fault Loop Impedance (Ze)

This module explains Ze, the external Earth Fault Loop Impedance of an installation, and its significance in fault protection. It covers how different electrical supply systems affect Ze and its role in ensuring compliance with safety standards.

4. Faults and Currents – Earth Fault Loop Impedance (R1+R2)

Building on the previous module, this session focuses on R1 and R2—the resistances of the line conductor and circuit protective conductor (CPC). It explores their impact on Zs calculations, permissible cable lengths, and the maximum Zs values for circuit breakers. The module also considers how voltage drop affects circuit performance and includes a discussion on Zdb for larger installations with multiple distribution boards.

By following these modules in order, you will gain a solid foundation in fault currents, circuit protection, and the basic principles of safe electrical design.