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Home / Technical Articles / Setting circuit breaker tripping with MS Excel spreadsheet

The protective unit of circuit breaker MUST fulfill:

  • Instantaneous trip setting Im < Iscmin for a circuit-breaker
  • Fusion current Ia < Iscmin for a fuse

The protective unit (or device) must satisfy the two conditions:

  • Its fault-current breaking rating must be greater than Isc, the 3-phase short-circuit current at its point of installation.
  • Elimination of the minimum short-circuit current possible in the circuit, in a time tc compatible with the thermal constraints of the circuit conductors, where:
    Time tc formula
How to set CB tripping? Try this tool!
Screenshot from MS Excel Spreadsheet - Setting tripping unit of circuit breaker

EEP has published tool which was designed by mr. Jignesh Parmar. The tool is in form of MS Excel Spreadsheet and covers calculations of tripping setting of circuit breaker.

Spreadsheet is free for download.

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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.

One Comment

  1. Nick Jhones
    Jul 12, 2018

    Circuit breaker formula has been given using it I have setting circuit breaker tripping with ms excel spreadsheet. for that protective unit of circuit breaker must be filled up.

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