I am looking at monitoring a 3 phase, 600vac system. To be able to do this I have to monitor the voltage reference. The units however are for 230vac and 120vac. Any suggestions on how to monitor the voltage?
You would need to source a transformer that steps down 600VAC to 12VAC or less. They are available. See this and this.
A field attached output cord with 5.5mm barrel plug is used to connect to IoTaWatt. A higher secondary voltage up to say 48V could be used with external resistors.
You would also need to check that your CTs are rated for 600V. Most UL are. The AcuCTs are.