Sept 22, 2018 rm 092 JDD

We will ask you
What is a ground fault?
How can a ground fault be detected?
What can interrupt a ground fault?
What do you the human do before you press the RESET button?

If you please, don't start any sentence with the word "So."

A ground fault is more than 5mA of AC current flowing from Hot to Ground through an unwanted conductance.

A ground fault can be detected by a differential transformer. The primary of the differential transformer is hot and neutral flowing in opposite directions, canceling each other out.

If a fault occurs, neutral current will be less than hot because of leakage to ground; thus a current "differential."

A current differential will produce an AC voltage on the secondary windings, thanks to Faraday's Law.

If the differential volts of the secondary is greater than a reference voltage which REPRESENTS exactly 5mA of differential current, then a comparator output will trigger a one-shot pulse of 200msec, connected to a DC current source that sends enough current to a solenoid coil so that the solenoid piston can pull one side of a HOT switch up to a latch, thus disconnecting HOT.

Before pressing the reset button, you the human must remove the unwanted conductance.

The reset button releases the latch and the proximal side of the HOT switch snaps back down to connect with the distal side.

What mechanical property does the proximal side of the switch have so the solenoid doesn't have to turn on "in reverse" for the proximal side to make contact with the distal side of the hot switch?

...it's a torsional spring...other questions may arise... like: What is a comparator: its inputs and output? How does a transformer work?