Im having trouble undertanding electrical grounding??

Question

cause someone put it in dumb people terms as to why grounding is necessary?? and what it does???

Answer 1

I doubt that you are dumb, because a dumb person would not be interested in this and asking the question.

I will assume that you are ignorant of most electrical theory and so I will try to explain simply.

Three are different kinds of "grounding" but they all have to do with keeping two areas at the same potential, meaning that they are not "charged" compared to one another.

House wiring:

The third wire in regular electric outlet in a house is a chassis ground.  Basically it connects the outside of something like a washing machine to the earth ground.  That means it cannot get charged up.  If a "hot" wire inside the washer comes loose and hits against the side of the washer, then you come along and touch the washer with your feet on the concrete, the electricity can flow through you into the ground.  This could kill you.  If the washer had a chassis ground, then as soon as the hot wire hit the side, the electricity would flow through the ground wire to ground.  This would normally trip a breaker or blow a fuse so that there would be no more hot wire, but if it didn't, the flow through the big ground wire would not leave enough charge to push flow through a human.  The chassis ground is an important safety feature in home electrical wiring.

Static ground:  static electrical charge can build up between two isolated points.  If you rub your feet on the carpet you can build up a charge compared to the doorknob.  When you get close to the doorknob the electricity can arc through the tiny air gap equalizing the charge.  If you started out with a ground wire that connected you and the doorknob, no matter how much you rubbed, any charge would cause a flow down the wire, keeping you and the doorknob at the same charge.  There can't be an equalizing arc if the two places are already at the same potential.  There is nothing to push them.  It is like two containers of water that are hooked together at the bottom through a small pipe.  If the level of both containers is the same, there is no oomph to push water from one to the other.  If water is added to one to make it much higher filled, the water will flow through the connection until the potential is equalized and the level is the same.  Two containers connected with a big pipe are "grounded" so you can't ever get the potential of one much above the other.

There are other systems where electrical grounding is used.  Also, the "return" wire in home wiring, the "neutral" is sometimes refered to as a ground because it, like the chassis ground, is connected to a big copper spike pounded into the ground.

Answer 2

Well, in "dumb people terms", electricity acts a lot like water in a pipe.  They both are pressurized and they flow.  If you cap off a water pipe, no water flows because it has nowhere to go.  Same principle with an electrical ground.  Without it, electrons have nowhere to go and there is no flow.

Answer 3

In early days when houses were becoming electrified for the average citizen (but as well as industrial uses), protection from electrical shock was a safety issue - and back then people weren't as concerned with safety as they are today (a bit over-concerned IMHO at times but I digress...)

To depend on the quality and durability of electrical insulating materials in order to prevent electrical shock has proven to be a bit of a gamble since environmental and physical forces can have an impact on this.

Fastening the external components which are conductive (and which the user may interface with) to an earthen connection provides a hard-wired path for any electrical currents which may develop a fault-driven conductive path to the external components (such as mounting hardware, metal case, etc...) in question, be it by age, heat, physical or environmental damage.

In doing so, such currents become in possession of a permanent path to earth instead of stealing a path to earth through your body, possibly electrocuting you.

Answer 4

The big ball under our feet is ground, as in ... dirt, and it is also called ground in terms of our earth's electrical potential level.

If something I touch has electrical potential and I am somehow touching a lower potential ... such as ground, electricity flows through me and I feel a shock.  If the electrical potential is strong enough, it will hurt and may kiill me.

For safety we often attach wires from electrical things to some earth ground so that any unwanted electricity (usually a wire with electrical potential that came loose or has it's insulation worn) will flow to ground through the wire instead of through you or me as a shock.

The easy way to do this is If your electrical outlet has a third hole in the center, it will (should if wired correctly) be ground (at ground electrical potential.)

Most three wire plugs then make us safer.

Where we can hurt ourselves with electricity easily (kitchens and bathrooms) our electrical outlets have a built in sensor and switch. When we plug in appliances, If the sensor measures electricity flowing to the earth ground, the switch will turn off the electricity to keep us from being hurt.