I think the easiest way for you to significantly improve the circuit from a safety perspective is to modify the layout in such a way that the high voltage part of the circuit is on one end of it and the low voltage part on the other.
A (very safe) alternative to using the hall sensor the way it is wired up right now: consider wrapping the current carrying wire around a ferrite core and putting a number of turns around the other side of the core to pick up the current (a very basic transformer). That way there is absolutely no need to go 'near' to the low voltage part of the circuit with the high voltage portion of the wiring.
That's called a current sensing transformer.
You could also place the hall sensor if you really want to use that in the gap of a slotted toroid around which the primary wire is wound a number of turns.
Adding a fuse is a basic precaution, you should size it based on the wire thickness that you are using.
You are doing pretty good but beware of knowing 'just enough to be dangerous'.
Alternatively once you've finished prototyping the circuit you could hand off the process of packaging it in a way that complies with the various standards to an electrical engineering firm, from a liability perspective that might be a good idea anyway.
A (very safe) alternative to using the hall sensor the way it is wired up right now: consider wrapping the current carrying wire around a ferrite core and putting a number of turns around the other side of the core to pick up the current (a very basic transformer). That way there is absolutely no need to go 'near' to the low voltage part of the circuit with the high voltage portion of the wiring.
That's called a current sensing transformer.
You could also place the hall sensor if you really want to use that in the gap of a slotted toroid around which the primary wire is wound a number of turns.
Adding a fuse is a basic precaution, you should size it based on the wire thickness that you are using.
You are doing pretty good but beware of knowing 'just enough to be dangerous'.
Alternatively once you've finished prototyping the circuit you could hand off the process of packaging it in a way that complies with the various standards to an electrical engineering firm, from a liability perspective that might be a good idea anyway.
hth