How would you explain electrical ground in laymens terms?

Question

Why is it called ground in the first place? Does it have to be on the floor?

Answer 1

It is called ground because of the first application. Ben Franklin invented the grounding rod that was used to prevent house fires during lightening storms. This is a long rod, usually made from copper, driven into the ground so as to send electrical surges into the earth for dispersal. Before it's invention, fires caused by lightening were the most common forms of fires in the world. In modern construction the ground is usually achieved by clamping the main ground wire to the cold water supply.

Answer 2

So called "Earth ground" is accepted as the ultimate 'ground because the earth itself is far more massive than anything on the earth, so it holds a lot of electrons, and it has a lot of space to hold electrons and charge carriers.

That being said, many objects, for example a cell phone, can be insulated from the earth, because we want it to be a portable device, and it is not necessary or practical to stop and connect to earth ground. For this reason, especially with regard to portable electronics, the electrical "circuit ground" can be any reference point that the designer decides to call "ground". If a simple circuit only has the need for a single ground, then it is simply called "ground"; however, sometimes a circuit will have more than one ground, such as a "digital ground" for digital electronics, and an "analog ground" for analog electronics, because it is often useful to isolate the two so they won't interfere with each other, especially if one is electrically noisy and it is desired that the other circuit be low-noise.

Sometimes "ground" is called "common", because it is usually it is a point that is in common with other components. This makes sense because ground is used as a reference point. When all the parts are referenced to a common ground, it makes it easier to understand how the circuit works, and the circuit behavior is more predictable.

Electricity is invisible to our senses, but it is similar to a lot of other things, so it helps to use analogies to explain it. So if you are flying in a plane and I say "what is your altitude", and you say '1000 feet', the implication is that you are 1000 feet above the ground, right? It's understood that ground is the reference point. Similarly, electrical ground is understood as the reference point. So I can simply say that some point is '5 volts', and you'll know I'm talking about a point where the voltage is 5 volts above ground.

These quantities require that you have a reference point in order to measure them. For example to measure a distance, you put the zero point of your ruler at the reference point, and then read the number at the second point, and there you have the distance from the reference. A voltmeter has two wires for the same reason that a ruler has two ends. Like distance, a voltage is a relative quantity and it only has meaning when one point is measured in relation to another. Often the reference point is ground, but it could be anything.

Answer 3

If you run an electrical supply, 3 phases, to a pump ( for example) and a problem occurred with the insulation of the cables the body of the pump could become 'live' and anyone touching the casing could be electrocuted as the live current went through their body to ground. To prevent this a fourth wire is run out(the ground or earth cable) to the pump casing to ground or earth the pump. In the construction industry if the potential is too high when tested a series of copper strips are buried with ground rods driven down and connected to them to form an 'earth mat'

Answer 4

In electrical engineering, the term ground or earth has the following meanings:

An electrical connection to earth. The part directly in contact with the earth (the earth electrode) can be as simple as a metal (usually copper) rod or stake driven into the earth, or a connection to buried metal water piping (though this carries the risk of the water pipe being later replaced with plastic). Or it can be a complex system of buried rods and wires. The resistance of the electrode-to-earth connection determines its quality, and is improved by increasing the surface area of the electrode in contact with the earth, increasing the depth to which it is driven, using several connected ground rods, increasing the moisture of the soil, improving the conductive mineral content of the soil, and increasing the land area covered by the ground system. This type of ground applies to radio antennas and to lightning protection systems.
In a mains (AC power) wiring installation, the ground is the wire that carries currents away under fault conditions. This power ground grounding wire is (directly or indirectly) connected to one or more earth electrodes. These may be located locally, be far away in the suppliers network or in many cases both. This grounding wire is usually but not always connected to the neutral wire at some point and they may even share a cable for part of the system under some conditions. The ground wire is also usually bonded to pipework to keep it at the same potential as the electrical ground during a fault. Water supply pipes often used to be used as ground electrodes but this was banned in some countries when plastic pipe such as PVC became popular.
In an electrical circuit operating at signal voltages (usually less than 50 V or so), a common return path that is the zero voltage reference level for the equipment or system. This signal ground may or may not actually be connected to a power ground. A system where the system ground is not actually connected to earth is often referred to as a floating ground.
An electrical connection to the inside surface of a Faraday cage. Any excess charges deposited on the inner surface of a Faraday cage will migrate to the outer surface of the cage, where they can produce no electric fields within the enclosure. For this reason, the inside surface of a Faraday cage behaves like an infinite sink for electrical charge from the perspective of objects within. Even if the Faraday cage itself is not connected to the Earth, the inner surface of the cage can be used in place of an earth connection.
A ground conductor on a lightning protection system used to dissipate the strike into the earth.

Answer 5

If you think of "Electricity" as a form of "Water" then we can proceed to:

A "Pump" pumps water under pressure to your house. (The pump uses an impeller that is correctly designed to do this)

A "Generator" creates an "Electrical Motive Force" (EMF) that pumps Electrons to your house. (The Generator uses a Moving Coil through a Magnetic field to do this)

1. You turn on your faucet and water comes out (the same as you turn on your TV and Picture/Sound come out).

2. The Water from your faucet goes into a "Drain" and out to the Sewer System (Gravity provides the force for this)

3. Electrons flow back on another wire (the neutral wire) to the generator that produced the Electrical Current.

4. The "Ground" Wire is used to take any excess Electrons and safely shunt them to ground.

Now in a Closed System the "Ground" circuit may be used to identify what we call the Neutral Circuit in your house wiring.

But, in essence, the "Circuit Ground" usually referes to the wires that conduct the Electrons back to the source.

It would probably make more sense if you took a Basic Electronics course and understood that ALL the electrons that leave the source MUST return to the source and ONLY their "Energy" is used to run the electrical device. ;-)

Answer 6

Because it goes to ground, literally. There are two kinds (by the way) grounded and grounding. Neutral is grounded and Ground (solid green or bare) is the grounding conductor. The ground removes 'excess' electricity from the appliance (anything that uses electricity) and prevents inadvertant shock.

Answer 7

Electrical potentials (voltages) are always "differences". The term "ground" or "grounding"
comes from the fact that the earth because of its size relative to other things you might
have around your lab has a GIGANTIC capacity to accept (or donate) electrons in response to
a difference in voltage of some other device -- hence the term "ground". So in most cases
whatever is attached to the earth (ground) is assigned a potential (voltage) of zero -- but
strictly speaking it is relative.

Answer 8

yes