programmable circuit breaker

Good idea.

It's a kilowatt of MeanWell switcher. Should be OK.

I am working on a solid state circuit breaker. So instead of your relay, I have two IGBTs back to back for ac operation.

You can do more than just measure the current. I have added an inductor on the output, so in case of a short and umlimited power on the primary side, the current rises defined before saturation.

You can detect the voltage over the switch/inductor, if too high you have a short. That will probably be much faster than the hall sensor

The inductor will limited the dI/dt, so the IGBTs are turned off before SOA is reached. Kick back pulse must be diverted off course, when/if the load decides not to be a short any more at the peak of the current ramp.

About the relay, you can detect the armature position by measuring the coil inductance. So to have the relay act faster, operate the relay at the knife edge where the armature is just pulled in. Then when current is decayed, the armature is moved instantly