Is there such an animal that would trip a circuit breaker when there is a loss of input power? Similarly with the relay system which energized to close the main contact to apply main/grid power to the service panel, but when there is a loss of grid power = loss power to the relay which disengage the main contacts which isolate the grid to the service panel. I am wondering as to is there such a compact plug and play device to do just that. Many thanks in advance and hope to hear your great insights...
A magnetic starter switch or magnetic contactor can do what you want. Most are designed for fairly heavy loads (8A and up), and they are not consumer-style plug-in devices but rather bulky boxes intended for permanently wiring. There are circuit breakers with this feature that you can mount in a panel (hopefully you have a panel type that one of these can fit). The on/off buttons are provided on the breaker itself and/or via a separate switch connected with its own wiring and mounted near the load (usually a machine of some sort).
The Fuji SC-03 is one example of such a circuit breaker: https://www.fujielectric.com/products/mc/mc_ms_tr_sc_neos.html
In answer to your original question, Yes there are breakers and devices that trip out breakers when the is a loss of prime power. Usually they are found in larger industrial sites where large motors create voltages at loss of power or there are parallel and redundant systems. They are not compact and they usually cost more than a Homeowner DIY is willing to pay.
Example see @John Zwinck go ahead and price his Fuji SC-03 and an Enclosure it would go in. I was thinking more along the line of Bassler's relay protection or a Smart Breaker depending on use.
What would be the residential need for such a device?
Smart switches have various behaviors on power cycle. I am pretty sure that some will allow setting a status on "power restored", though it may take some digging to figure that out - fortunately manuals are generally available online before buying. But if you go that route, you have to be careful about what you are connecting. Limitations may include:
- Total power (actually, every switch has that limit, but it is generally far below the 15A or 20A capacity of a circuit breaker)
- LED/CFL/Incandescent compatibility
- Motor compatibility
- Neutral vs. ground vs. leakage current for getting power, which may affect compatibility with various devices