These tenants must have been able to change the CT ratio via that button or "ZAP" the meter by means of an HV surge nearby.
In my years in CT metering I have found the odd CT meter ( electromechanical ) with the wrong multipler, eg. X 30 ( 150 / 5 Amps )while the CT's were at X 80 ( 400 / 5 Amps ). The meters we used at WEPB were mostly --/5 Amp ( blank 5 )meters and the readings needed a multipler attached to it.
These were on multitap CT's 150/250/400/5 Amps.
Can't prove wheather it was an utility error or changed CT tappings at a later stage by persons unknown.
A lot of CT chambers have seals missing in tenancy buildings.
Links left closed at testblocks or blown potential fuses were more common findings at CT checks in the field, or the transposed phase to current circuit.
