[ELI5] What does it mean to be “grounded” against electricity, and why does it keep you safe?
In: 66
You as a person being grounded (at the same potential as the neutral wire coming into your house) is bad. If you touch one of the hot wires coming and are grounded, current will flow from the hot wire, through you, to the ground because the neutral wire is at ground potential.
A safety ground (or chassis ground) is important for devices with a conductive outer chassis (most appliances for example). Let’s say your metal toaster has a frayed hot-wire inside it. This wire touches the metal chassis of the toaster. It is now at the same potential as the hot wire. When no one is touching it it’s a open circuit, no current flow. But you come in to the kitchen and touch it while your feet are on the floor, you have created a full circuit and current will flow. Ouch
Now a number of factors come into play that determine how much current will flow. If you are on the 2nd floor of your house wearing rubber boots and your hand is dry, you might only feel a tingle because your insulated from ground potential. If you just got out of the shower and are barefoot on the basement floor, you might have a worse day.
This is where a safety ground comes into play. The safety ground is wired up to a grounding rod buried into the ground, usually where your electrical meter is. This is wired to the chassis of your metal toaster, so that when the hot wire in the toaster touches the chassis, it creates the circuit instead of you. Also this will act like a short circuit and immediately trip your circuit breaker.
Latest Answers