Is It Safe to Use MCBs as Regular On/Off Switches?

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SUMMARY

Using Molded Case Breakers (MCBs) as regular on/off switches is possible, particularly with modern Miniature Circuit Breakers compliant with BS60898 standards. However, this practice is considered poor design due to the clunky operation and potential lifespan reduction from repeated switching. Older MCBs are generally not designed for frequent functional switching, and users must verify compliance with local codes, such as the UL code in the United States, before implementation.

PREREQUISITES
  • Understanding of Molded Case Breakers (MCBs)
  • Familiarity with British Standards (BS60898)
  • Knowledge of local electrical codes (e.g., UL code in the USA)
  • Basic electrical installation design principles
NEXT STEPS
  • Research the specifications and compliance of MCBs under local electrical codes
  • Learn about the differences between modern and older MCB designs
  • Explore best practices for electrical installation design
  • Investigate alternatives to MCBs for functional switching applications
USEFUL FOR

Electrical engineers, electricians, and anyone involved in electrical installation design or maintenance who seeks to understand the practical applications and limitations of MCBs.

M.Kalai vanan
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can MCB be used as normal on/off switch?
 
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M.Kalai vanan said:
can MCB be used as normal on/off switch?

What's an MCB? What is the context of your question?
 
Assuming Molded Case (Circuit) Breaker - then yes, but it is clunky, heavy to switch. In a larger application the MCB can be the main disconnect switch.
 
MCB is common terminology here in England for Miniature Circuit Breaker and modern MCB's that comply to BS60898 can be used as functional switching for say lights but in the capacity of design of the installation this would be regarded as poor design and practice. Older MCB's you will often find are not designed as a functional switching device and the repeated switching will reduce its lifespan dramatically.

As the BS number I have quoted is a British Standard you will need to relate to your own countries coding system for the MCB you are discussing then, I believe America using a UL code then look up whether your particular device is compliant for frequent functional switching.

There's no Yes or No answer here as its down to several factors some of which I've touched on.

This is the best answer I can give with the info supplied.
 

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