Premium Membership ♕

Save 50% on all Video Courses with Enterprise Membership Plan and study specialized LV/MV/HV technical articles and guides.

Home / Technical Articles / Functions Performed by Electrical Switchgear
Functions Performed by Electrical Switchgear
Functions Performed by Electrical Switchgear (on photo Blokset switchboard withdrawable unit/cassette)

Electrical Switchgear

National and international standards define the method for making electrical distribution circuits as well as the purpose and functions of switchgear. There are three main functions, namely:

  1. Circuit protection takes three main fault types into account:
    1. Overloads,
    2. Short-circuits (Both of which adversely affect the lifetime of cables and loads)
    3. Insulation faults, harmful for persons and equipment.
  2. Isolation is used to separate a circuit or a device from the remainder of the installation to allow 100% safe operation,
  3. Control allows the user to take voluntary action on installation operation:
    1. When such action takes place in normal operating conditions (on load, with no overcurrent) in order to energise or de-energise all or part of the installation, control is said to be “functional”,
    2. When such action is essential (whatever the load condition of the installation) in order to immediately de-energise all or part of the installation, control is said to be of the “emergency stop” kind.

Three main functions of electrical circuits:

  1. Protection,
  2. Isolation,
  3. Control,

The switch is used for:

  1. Control,
  2. Often isolation.

For protection it must be combined with:

  1. Circuit-breaker,
  2. Fuses,
  3. Residual current device (if necessary).

A variety of switchgear perform all or some of these three main functions. The following table situates the role of the main switchgear:

Functions perfomed ProtectionsIsolationControl
FuseYes (3)YesNoNoNo
SwitchNoNoYes? (1)(2)Yes?Yes
Disconnector – fuseYesYesNoYesNo
Switch – fuseYesYesYes? (1)(2)Yes?Yes
ContactorNoNoNo NoYes
Circuit-breakerYesYesYes? (2)Yes?Yes

Yes –  Basic function of the switchgear considered (always performed)
Yes? –  Additional function possible (not always performed)

(1) Possible with a switch with automatic opening.
(2) Possible with addition of a “Residual Current Device (RCD)“.
(3) gG fuse only

Resource // Schneider Electric – Low voltage switches

Premium Membership

Get access to premium HV/MV/LV technical articles, electrical engineering guides, research studies and much more! It helps you to shape up your technical skills in your everyday life as an electrical engineer.
More Information

Edvard Csanyi

Electrical engineer, programmer and founder of EEP. Highly specialized for design of LV/MV switchgears and LV high power busbar trunking (<6300A) in power substations, commercial buildings and industry facilities. Professional in AutoCAD programming.


  1. Achmad Zainuri Rajasa S.P
    Oct 19, 2017

    @Edvard Casanyi : it is very useful site adding a knowledge and experience

    @Gurprme eet Singh : I would like to know more about CNC programming. could you give a reference about that ? Thanks a lot.

  2. ashafa
    Oct 29, 2015

    informative….very helpful

  3. gurpreet singh
    Nov 15, 2014

    My name is Gurpreet Singh from Virdi enterprises , we are the sheet metal parts manufacturer in INDIA .
    We specialize in custom metal fabrication projects for low or high volume, high quality production. Our facility is flexible equipped to handle prototype, short-run and long-run production work at competitive prices and best services.
    We sincerely hope could be your reliable sheet metal parts supplier for your projects , looking forward to hearing from you, thanks.
    Commonly Manufacturing Fields

    · Custom fabricated sheet metal products
    · Metal covers, Db boxes spn & tpn , tubes, and cabinets
    · Metal panels
    · Custom metal shelving and brackets
    · Metal electronics components
    · Vehicle components
    · Lighting components
    · Laser components
    · Plastic components
    · Cnc Plasma cutting components
    · Electrical HT, LT / Drowout Panel Parts
    Our Capabilities

    · CNC Machining
    · Stamping and Punching
    · CNC Laser Cutting
    · CNC/Automatic Lathe
    · Fastener and Fitting Insertion
    · Product Assembly
    · Highly skilled sheet metal fabricators
    · Coated, Plated, Anodized finishing
    Materials Range

    · Steel
    · Stainless steel
    · Aluminum
    · Copper
    · Brass
    · FR ( Fire Resistant )
    · Glass apoxy , bekalite etc.

Leave a Comment

Tell us what you're thinking. We care about your opinion! Please keep in mind that comments are moderated and rel="nofollow" is in use. So, please do not use a spammy keyword or a domain as your name, or it will be deleted. Let's have a professional and meaningful conversation instead. Thanks for dropping by!

42  +    =  fifty one

Learn How to Design Power Systems

Learn to design LV/MV/HV power systems through professional video courses. Lifetime access. Enjoy learning!

Subscribe to Weekly Newsletter

Subscribe to our Weekly Digest newsletter and receive free updates on new technical articles, video courses and guides (PDF).
EEP Academy Courses - A hand crafted cutting-edge electrical engineering knowledge