During yesterday’s inspection I turned on the oven while I was looking at the electrical panel panel. I measured the amperage on the two sides of the 240 V breaker; one side measured .3 A and the other side measured 4.8 A.
The circuit had no grounded conductor/neutral installed, only a grounding conductor. Wouldn’t the difference in amperage indicate this appliance has 110 V components and a grounded conductor/neutral needs to be present?
It’s possible the oven reached the temperature setpoint and turned off between your two readings. Robert is correct as usual old range/oven wiring had no grounded conductor just three wires. No surges!