In a typical residential electrical system, the voltage supplied to a home is 110V AC in North America. The terms "ground" and "neutral" refer to different points in the electrical system.
Before the appliance is plugged in and turned on, the voltage from ground to neutral is close to zero. This is because the neutral wire is bonded to the ground at the main electrical panel, resulting in a common reference point.
During the operation of a large inductive load like a vacuum cleaner, the voltage from ground to neutral can experience slight fluctuations due to the current flowing through the load and the resistance of the electrical wiring. The fluctuations are typically small and may not be noticeable under normal conditions.
After the appliance is turned off and unplugged, the voltage from ground to neutral returns to its normal state, which is close to zero.
It's important to note that the voltage from ground to neutral can vary based on the specific electrical system, wiring conditions, and the presence of any electrical faults or abnormalities. If you suspect any issues with the electrical system or experience significant voltage deviations, it's recommended to consult a qualified electrician to assess and address the problem.