I would like to install some additional appliances in a room that already has a couple of heavy equipment machines running in it. These are sensitive machines, so instead of having the main circuit breaker trip when there is an overload, is there a device that I could connect to the outlet and then connect the new appliances to these devices? My goal would be to have power to these specific appliances cut off instead of tripping the breaker.
If you load is a motor, a VFD could be this device where you can set the max current.
I have used it myself on an asynchronous machine which was more than capable of pulling more current under high load than my utility company's service would allow and thus melt the fuses.
It is about what we call discriminative tripping. divised into both:
- current-level discrimination
- time-based discrimination
The type of the circuit breaker defines the tripping. For type B, for instance, the current is 3 to 5 times the rated current for a time between 0.04 to 13 seconds. You can find the curve for each circuit breaker (inverse time curve).