On Elspec G5 devices through 1.2.2.19, a person with physical access to the device can reset the Admin password by inserting a USB drive (containing a publicly documented reset string) into a USB port.
https://www.cisa.gov/news-events/ics-advisories/icsa-25-345-08
https://www.elspec-ltd.com/support/security-advisories/
https://www.elspec-ltd.com/metering-protection/g5-multi-functional-digital-fault-recorder/