Difference in Layman's terms...

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gappvembe

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Between a ground (green) and a neutral (white) wire. They both go to the same place. Why do you need both?

This is for my boss. I can't really explain it to him. Maybe an exact article in 250 you can refer me to.

Any help would be great.
 
In laymens terms the difference is very simple. The white wire usually carries current, the green wire usually does not. In normal operation on a two-wire circuit (with the green wire being the third wire) the white wire will carry the exact same amount of current as the black or "hot" wire. The green wire will carry current only if there is a malfunction. In which case the green wire will hopefuly return the majority of the current to the source rather than the current passing through the user or some other return path. The green wire is the "safety belt" that protects the user.
 
from http://www.howstuffworks.com/question110.htm

Let's start with what the holes in an outlet do. When you look at a normal 120-volt outlet in the United States, there are two vertical slots and then a round hole centered below them. The left slot is slightly larger than the right. The left slot is called "neutral," the right slot is called "hot" and the hole below them is called "ground." The prongs on a plug fit into these slots in the outlet.
If you have read How Batteries Work, you know that electricity must flow in a circuit. In a battery, electricity flows from one terminal of the battery to the other. In a house outlet, power flows from hot to neutral. The appliance you plug into an outlet completes the circuit from the hot slot to the neutral slot, and electricity flows through the appliance to run a motor, heat some coils or whatever. Let's say you plug a light bulb into the outlet. The power will flow from the hot prong, through the filament and back to the neutral prong, creating light in the process.

What if you were to plug a thick strand of wire straight from the hot slot to the neutral slot of an outlet? Unlike an appliance, which limits the amount of electricity that can flow to 60 watts (for a light bulb) or 500 watts (for a toaster), the wire would let an incredible amount of electricity flow through it. Back in the fuse box, the fuse or circuit breaker for the outlet would detect this huge surge and it would cut off the flow of electricity. The fuse prevents the wires in the wall or the outlet itself from overheating and starting a fire.

The ground slot and the neutral slot of an outlet are identical. That is, if you go back to the fuse box, you will find that the neutral and ground wires from all of the outlets go to the same place. They all connect to ground (see How Power Distribution Grids Work for details on grounding). Since they both go to the same place, why do you need both?

If you look around your house, what you will find is that just about every appliance with a metal case has a three-prong outlet. This may also include some things, like your computer, that have a metal-encased power supply inside even if the device itself comes in a plastic case. The idea behind grounding is to protect the people who use metal-encased appliances from electric shock. The casing is connected directly to the ground prong.

Let's say that a wire comes loose inside an ungrounded metal case, and the loose wire touches the metal case. If the loose wire is hot, then the metal case is now hot, and anyone who touches it will get a potentially fatal shock. With the case grounded, the electricity from the hot wire flows straight to ground, and this trips the fuse in the fuse box. Now the appliance won't work, but it won't kill you either.

What happens if you cut off the ground prong or use a cheater plug so you can plug a three-prong appliance into a two-prong outlet? Nothing really -- the appliance will still operate. What you have done, however, is disable an important safety feature that protects you from electric shock if a wire comes loose.


Thanks everyone. This is the kind of explination I needed.
 
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I explain by saying that the sole purpose of the EGC is to trip the breaker (or blow the fuse) when any metal part that should never become energized does so.

gappvembe said:
The ground slot and the neutral slot of an outlet are identical. That is, if you go back to the fuse box, you will find that the neutral and ground wires from all of the outlets go to the same place. They all connect to ground.
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In my opinion, this description is widely misunderstood. It implies that the earth, and not the source neutral, is sought by voltage. I prefer to say that the EGC's connect to the neutral, which is then grounded.

One of my ex-employees insisted that electricity returns to the power company through the earth. He may have meant their main office :roll:; he would end discussions when I tried to correct him. That's one of the reasons he's an 'ex'.

Once, he came up to me and asked if I knew the primary colors. (He was an art student in college. :roll:) When I asked "pigment or light?", he said "I knew you wouldn't just give me an answer" and walked away.

He later insisted that "the" primary colors (red, yellow, and blue) of paint combined to make white.

gappvembe said:
Thanks everyone. This is the kind of explination I needed.
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You didn't ask this question just to answer it yourself, did you?
 
LarryFine said:
In my opinion, this description is widely misunderstood.
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This is the reason that I have said for several years that the Equipment Grounding Conductor should be replaced with an Equipment Bonding Conductor.
 
these wires only "go to the same place", as you put it, at the Service entrance. They are seperated anywhere downstream, for the reasons already stated.
 
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