Size of Main CT to Buy

Hello,

I have a split-phase US electrical service that is rated for 300Amps.

The actual current is measured at 18Amps for phase A and 13Amps for phase B.

Should I use current transformers that are rated for the nominal incoming amperage of 300A or what I actually measure during normal use?

Thank you,
Jon

By what you are saying, 200A CTs should work.