Measuring AC Current at High Voltages (up to 600VAC)
For safety reasons, AC current measurement typically performed using either a current transformer (CT), or a Rogowski Coil, or a Hall Effect sensor.  For various reasons&mdash;not the least of which are equipment safety and personnel safety, current measurement in an AC power distribution line is typically not performed by inserting a series resistance into a current carrying path and measuring the voltage drop across the resistance.

And in addition other's comments to your question, be certain to provide sufficient galvanic isolation between the high voltage system and any low voltage system that uses the sampled output from the high voltage system. Galvanic isolation is typically implemented via photonics (e.g., opto-coupler), or electromagnetic induction (transformer), or electrostatic field (capacitance), or an isolation amplifier component (example, example), or some combination thereof.  (NB: A CT, a Rogowski Coil, and a Hall Effect sensor provide at least some level of galvanic isolation. Additional isolation might still be necessary, however.)

The measurement system must also be designed to operate safely for the specific measurement category wherein it will be used.

:: WARNING ::

Failure to provide (a) adequate galvanic isolation and (b) adequate "measurement category" design can result in destroyed equipment and can kill people when a circuit fault occurs. So this is very important.

See also:


https://content.fluke.com/promotions/promo-dmm/0518-dmm-campaign/dmm/fluke_dmm-chfr/files/safetyguidelines.pdf
https://www.ni.com/en-us/innovations/white-papers/13/understanding-and-trusting-isolation-specifications.html