@carlsbad2
Sorry I didn’t really answer your question. As I understand it, the most common cause of a surge inside the home is when a large inductive load (motor) is turned off. The magnetic field has inertia and until it collapses is present and the motor tries to feed that energy back into the system.
This is the best description I've found:
...However, because you have current flowing in an inductor at the time of turn off there will be a transient voltage produced. Much of this voltage will occur across the power switch contacts. There maybe some very short transient rise in voltage on the supply wiring. Could be several thousand volts next to the switch and diminish as you move further from vacuum connection point. ...
https://forums.mikeholt.com/threads/can-a-vacuum-cleaner-cause-a-surge.60537/