circuit breaker

I would try connecting one side of a N/O contact of the relay to the load side of the breaker. Then the other side of the N/O contact connected to earth via a resistor.

Value of the resistor should be supply voltage divided by required current to trip the breaker (maybe plus ten or fifteen percent).

Coil of the relay to be energised by controller.

Ensure that the relay contacts and relay are of sufficient current rating.

This is by no means something I have tried but if I was asked to come up with what you're after then this is what I would try first. So if you blow your kit up, it ain't my fault.

Al

The out put from sensors or microcontrollers have to be made compatible with the relay system of the breaker . The voltage and power requirement of the relay that operates the breakers need higher voltage and higher power. The output signal from the micro controller will not be compatible. so an intermediate circuit and board that amplifies incoming signal is essential to operate the trip circuit system of the breaker..

You don't say how much current you are proposing to pass through the realy. As stated by others, the relay must be capable of carrying the load the circuit breaker is seeing. This is a rather risky proposal.

My advice would be to use a molded case circuit breaker (E frame) rather than the small Q frame breakers. These molded case breakers are more expensive, but they can be ordered with a shunt that can be wired to your relay to safely trip the breaker on demand.

Take a close look at the shunt-trip coil rating for voltage & current requirements. In order to trip the breaker via the shunt-trip control the I/O output must be rated at a high enough voltage and current to satisfy the electrical demand. Most shunt trip devices require less than 5 amps of current (usually rated in millamps) in order to operate properly. If the legend is not legible on the breaker, contact the manufacturer and they will supply you with the specifications. If need be, the shunt trip coil in most molded-case breakers is fairly easy to replace.

For example: If the shunt trip requires 120VAC at 500mA (.5 amps) then your I/O must be rated at 120VAC at (1.25 x .5 amps) .625 amps or 625mA to allow for the current inrush that will occur when power is initially applied to the circuit. If your I/O is not rated high enough to accomodate the load, use an interposing relay between the I/O and the shunt-trip circuit. The I/O output should be attached/wired to the coil on the interposing relay and the load should be switched by the relay contact(s). Be sure to choose a relay that meets the voltage & current requirements for safely switching/interrupting the load. If you are using DC out of your I/O, make sure that the relay coil is a DC rated unit. Most breaker manufacturers provide wiring diagrams and instructions on how to properly wire their shunt-trip circuits.

Good luck and be careful.

With insufficient information describing the problem, there are many answers. I would carefully read the specification for the circuit breaker and also check for application notes. I personally prefer a UVR or UVT over shunt trip if the consequences of failing to turn of the circuit breaker can be catastrophic.

You want to cut supply, right?

You have a relay that trips under certain conditions, and under these conditions you want to cut the power, right?.... Than why trip the breaker?, simply connect the breaker load side through the normally closed contacts of your relay, and that's it. resetting the system and resetting your relay will resume power. If you have spare contacts on your relay use it as "tripped" indicator, and with another set is you have it, you can make a "reset" button.

Personally, I never liked the idea of intentionally tripping a breaker. a matter of taste...

Wangito

If it is a small breaker for a circuit small enough to fit in the relay contact ratings, I agree with Wangito, just use the relay. But if it is a big breaker, are you sure you need to do it that way? breakers are not really meant to be used as switches, they tend to wear out. If it is something involved in an emergency circuit, then that is the way to do it, but if it is every day, use a contactor.