a/c main or circut monitoring up to 300 amps .. non-invasive / clamp on.

https://www.milesight.com/iot/product/lorawan-sensor/ct10x
 
Self-Powered Operation
Superior Accuracy with Up to 3.3kHz Frequency
Real-time Accumulated Ampere Hour Calculation
Non-invasive Installation
Irregular Current Status Alert
External Wire Temperature Sensor
Detachable and Cable-Free Design
LoRaWAN® Wireless Technolog