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trip unit (circuit breaker)

A trip unit is the part of a circuit breaker that opens the circuit in the event of a thermal overload, short circuit or ground fault.  An open circuit will not conduct electricity because either air, or some other insulator has stopped or broken the flow of current in the loop.

There are two types of trip units, electromechanical (also called thermal magnetic) and electronic.   An electromechanical trip unit has moving parts; it combines a current-sensitive electromechanical device with a thermal-sensitive device and the two devices work together to determine when to  mechanically open the circuit. An electronic trip unit is programmable device which measures and times current flowing through the circuit breaker and initiates a trip signal when appropriate.

This was last updated in June 2011

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If too much load is placed on the breaker then it might start tripping intermittently. By then it's a bit too late and you'll probably have to change the circuit breaker. If that's the case you can get one at http://www.allelectricneedsinc.com and look up technical datasheets if needed.
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