Clamp meters

[MetalMonkey]

Or if you have money burning a hole, one of these:

https://www.testinstrumentsolutions...-line-splitter-with-earth-leakage-measurement

One nice thing about a line splitter is they often give you a turncoil so you can get better resolution on small currents.

Sidenote - TIS rebrand a lot of Brymen gear, usually with a markup.