How does a 3 pin plug work?

Answer 1

Standard US 120V plugs have a pin for hot, neutral, and ground. Hot is the main feed for the electricity. Neutral is the return wire for the electricity. Neutral is the wider blade on a polarized plug. Neutral is a safety wire. It is designed to be at the same potential as earth and should have no energy flowing through it under normal circumstances. It is designed to ground conductive components the user may touch. In the event of a short energy flows through the ground wire blowing the breaker, instead of through the user electrocuting them. This is why double insulated devices with no conductive parts for the user to touch have no ground pin. This is also why you should never bypass the ground pin. It is there for your safety.

Answer 2

A short answer:

The third pin in the plug is the Earth pin. It is connected to the Earth via a low-resistance path, and an Earth wire is never connected to either of the two current-carrying wires.

All equipment with external metal surfaces has the earth wire connected to the case, so that all equipment cases are connected together and to the earth, making shocks much less likely.

When a short circuit happens in a faulty device, excess current may flow through the Earth wire to trip a ciruit-breaker or open a fuse, thereby removing the load from the supply and rendering it safe.

Answer 3

It is so there is no confusion about how it must be inserted and what type of outlet is required. Many plugs use different shapes and sizes to determine the amount of power available or the amount of power required.

For instance, a 30Amp US plug is very different from a 15Amp US plug because you cannot allow consumers to plug a 30A device into a 15A outlet. Similarly, you cannot plug a 15A device into a 30A outlet because they're different, and they are different so that a 30A circuit breaker is not expected to protect a user of a 15A device, when something goes wrong.

A "larger" prong on a plug is often used for the "neutral" wire, perhaps because the receptacle hole is larger and would be more dangerous if it were the hot wire.

Answer 4

Each pin has a separate wire connected to it. One is for "hot", one is "neutral", and one is "ground." in older two wire systems the two pins are for hot and neutral.

Answer 5

Because this uses a ground, a two pin does not have a ground and is not as safe as having a ground.

If you notice, older products used a two pin, newer ones use three.

Answer 6

Because it has three pins used to connected three wires, often a power, return, and ground.

Answer 7

They are important because they are used to plug in to the electricity supply. The three pins are live, neutral and earth, also called hot, neutral and ground.