Hello,
most non low-power electric devices have a ground pin to protect if a shortcut or something happens (Correct me if I got that wrong, already)
But how does it work? As far as I know you always need a completed circuit for electricity to flow. So how is an electric circuit closed if electricity flows to the ground?
In: Physics
The complete circuit for mains electricity in your house is from the transformer on the pole, down the hot wire, through your device, up the neutral wire, and back to the transformer
So how is ground able to complete this circuit?
Because we tied neutral to ground!
In your breaker panel all the neutral wires end up tied to all the ground wires which are all tied to a long metal rod in the dirt outside. This ensures that neutral is at roughly 0 volts relative to ground and hot is at 120VAC or 230VAC (depending on your country) and not 120VAC + 5000 VDC because the transformer is just floating at some high DC voltage.
Because we tied them together back at the panel, a valid path for current in the event of a fault case is also transformer->hot wire->short to device case -> ground wire -> breaker panel -> neutral return -> transformer
We leave ground on its own pin so that it isn’t carrying current and is always at 0V not 1-5V above depending on the current in the neutral wire.
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