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CCC79cedric:
You and many other electricians need to study electrical circuit theory, and how the various components work that you connerct together.
What is a shunt trip breaker, and how does it work?
I have never seen or worked with one, and therefore I don't know. What does the word shunt mean? See https://www.dictionary.com/browse/shunt . In a somewhat more general statement --- a shunt is something in parallel.
An ordinary single pole circuit breaker has one actuator mechanism to trip the breaker. In a Sq-D QO breaker this is a single U shaped bimetal device that is both a thermal and magnetic actuator.
In electrical circuits using the concept of positive logic parallel switches perform the logical function of "inclusive OR". This means that if any one or more inputs are 1, then the output is 1. Whereas a two input "exclusive OR" has a 1 output when only one input is a 1. This is the basis of a binary adder.
Back to the shunt trip breaker. This is a breaker where more than one mechanical thing can trip the breaker. These would be at least the breaker lever, one or more current sensors, and one or more remotely triggered actuators.
Looking on the internet I have seen a QO with a side package with two terminals for the remote turn off control. These would be wired to a voltage source thru a series switch.
Look at the data sheet for your breaker and see if it tells you how the breaker works. Otherwise make measurements on your breaker, and figure out how it works.
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