LV switchgear: functions and selection

The three basic functions provided by low voltage switchgear for the related electrical circuit are:

• Electrical protection
• Isolation
• Local or remote switching

This chapter explains these functions, describes the most common types of low voltage protection and/or control switchgear. With a special focus on circuit-breakers: their characteristics, and how to select circuit-breakers, taking into account selectivity and cascading techniques.

Chapter H - Contents

• The basic functions of LV switchgear
  • LV switchgear functions - Electrical protection
  • LV switchgear functions - Isolation
  • LV switchgear functions - Switchgear control
• The switchgear
  • Elementary switching devices
  • Combined switchgear elements
• Choice of switchgear
  • Switchgear selection
  • Tabulated functional capabilities of LV switchgear
• Circuit-breaker
  • Standards and description of circuit-breakers
  • Fundamental characteristics of a circuit-breaker
  • Other characteristics of a circuit-breaker
  • Selection of a circuit-breaker
  • Coordination between circuit-breakers
  • Selectivity MV/LV in a consumer’s substation
  • Selectivity of Residual Current Devices (RCDs)
• Maintenance of low voltage switchgear

Related technical guides

Selectivity, Cascading and Coordination Guide

Get all required information to verify your electrical distribution design's robustness, considering overloads and short circuits.

Combine the benefits of selectivity and cascading to maximize power availability of your LV design at optimized cost.

Find Schneider Electric's coordination data for ACBs, MCCBs, MCBs, switches, busbar trunking (busways), motor starters and more.

Download the guide (.pdf)