One way to make non-grounded receptacles safer, without rewiring.

[@richardl6751]

At 3:20 You are correct. It compares incoming current throught the hot lead to the outgoing current through the neutral lead. If the difference it greater the 0.006 amp (6 milliamps) it will trip.

[@borderpropertyinspections2634]

Thanks for that, I wish I knew more but I only have the basics.

[@StorytellerSueW]

Can't hear a thing.

[@borderpropertyinspections2634]

Sound seems good to me.