Protection against electric shocks and electrical fires

In this chapter, you will discover:

• the dangers related to electric shock, and the protection measures defined by the IEC 60364 standard (basic protection, fault protection and additional protection). And how to implement these protection measures with TN, TT and IT earthing systems
• the different electrical fire risks and causes, and the technical solutions to mitigate these risks

Chapter F - Contents

• Protection against electric shock
• Types of protection against electric shock
• Additional protection: High sensitivity RCDs
• Implementation of the TT system
  • TT system - Principle
  • TT system - Practical aspects
• Implementation of the TN system
  • TN system - Principle
  • TN system - Preliminary conditions
  • TN system - Earth-fault current calculation
  • TN system - High fault current-loop impedance
• Implementation of the IT system
  • IT system - Principle
  • IT system - Fault protection
  • IT system - Implementation of protections
  • IT system - Practical aspects
• Residual Current Devices (RCDs)
  • Description of RCDs
  • Form factors of RCDs
  • Types of RCDs
  • Sensitivity of RCDs to disturbances
  • Coordination of residual current protective devices
  • RCDs selection in presence of DC earth leakage currents
• Other protective measures against electric shocks
  • Extra Low Voltage (ELV)
  • The electrical separation of circuits
  • Class II equipment
  • Out-of-arm’s reach or interposition of obstacles
• Protection against electrical fire risks
  • Protection against fire due to earth faults
  • Protection against arc faults in cables and connections (AFDD)
  • Protection against electrical fire risks - synthesis