LV switchgear: functions and selection: Difference between revisions

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== General  ==


==== Methodology and definition  ====
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The three basic functions provided by low voltage switchgear for the related electrical circuit are:
* Electrical protection
* Isolation
* Local or remote switching


==== Overcurrent protection principles  ====
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.
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==== Practical values for a protective scheme  ====


==== Location of protective devices  ====
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==== Conductors in parallel  ====
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== [[Practical method for determining the smallest allowable cross-sectional area of circuit conductors|Practical method for determining the smallest allowable cross-sectional area of circuit conductors]]  ==
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==== General  ====
{{Related-guides-intro}}
{{RelatedGuide
|image=Hp-highlight-selectivity-guide.png
|title=Selectivity, Cascading and Coordination Guide
|text=Get all required information to verify your electrical distribution design's robustness, considering overloads and short circuits.


==== General method for cables  ====
Combine the benefits of selectivity and cascading to maximize power availability of your LV design at optimized cost.


==== Recommended simplified approach for cables  ====
Find Schneider Electric's coordination data for ACBs, MCCBs, MCBs, switches, busbar trunking (busways), motor starters and more.
 
|btn-text=Download the guide (.pdf)
==== Busbar trunking systems  ====
|link=https://www.se.com/ww/en/download/document/LVPED318033EN/
 
}}
== [[Determination of voltage drop|Determination of voltage drop]]  ==
 
==== Maximum voltage drop limit  ====
 
==== Calculation of voltage drop in steady load conditions  ====
 
== [[Short-circuit current|Short-circuit current]]  ==
 
==== Short-circuit current at the secondary terminals of a MV/LV distribution transformer  ====
 
==== 3-phase short-circuit current (Isc) at any point within a LV installation  ====
 
==== Isc at the receiving end of a feeder in terms of the Isc at its sending end  ====
 
==== Short-circuit current supplied by an alternator or an inverter  ====
 
== [[Particular cases of short-circuit current|Particular cases of short-circuit current]]  ==
 
==== Calculation of minimum levels of short-circuit current  ====
 
==== Verification of the withstand capabilities of cables under short-circuit conditions  ====
 
== [[Protective earthing conductor|Protective earthing conductor]]  ==
 
==== Connection and choice  ====
 
==== Conductor sizing  ====
 
==== Protective conductor between MV/LV transformer and the main general distribution board (MGDB) ====
 
==== Equipotential conductor  ====
 
== [[The neutral conductor|The neutral conductor]]  ==
 
==== Sizing the neutral conductor  ====
 
==== Protection of the neutral conductor  ====
 
==== Breaking of the neutral conductor  ====
 
==== Isolation of the neutral conductor  ====
 
== [[Worked example of cable calculation|Worked example of cable calculation ]]<br> ==

Latest revision as of 13:46, 26 January 2024

Banner-chapter H.jpg

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


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