Umevamia usichojua
Kifupi earth ikiwa imechoka umeme mwingi utapotea na Ndiooo maana umashauriwa kuikagua mara kwa mara na kuhudumia kwa kuimqagia maji eneo lake
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Hiyo sayansi ya umeme siku hizi mnaisoma wapi? Flow ya umeme unaokuja nyumbani kwako ni tofauti ya flow ya maji inayokuja nyumbani kwako. Kwa lugha rahisi mambo yako hivi:
Kuna waya mbili, ya live na ya neutral. Hiyo ya live inatoka kwenye chanzo (source) cha umeme wako ambacho ni transformer ya tanesco iliyopo karibu na wewe hadi kwenye kifaa chako (appliance eg jiko) kupitia main switch yako na switch yako ya ukutani ulipomeka waya wako wa kifaa chako. Ukitoka pale unarudi kwenye source kupitia neutral wire. Earth wire ni kuku protect wewe utakapogusa appliance casting yake from electrocution from stray currents. Hizi stray currents zinachukuliwa na earth wire na kupelekwa kwenye earth rod kwenye ground na baadaye kuchukuliwa na neutral wire hadi kwenye chanzo ie transformer. Ni kwa usalama wako unapogusa hicho kifaa kikiwa kimeshawashwa. La sivyo umeme utapitia kwenye mwili wako pia kabla ya kurudi kwenye source. You will be executed.
Jaribu kusoma jibu la swali hili hapa linalofanana na tatizo lako kama utaweza kuelewa lugha iliyotumika:
Q: If the neutral wire is grounded, why is it still necessary to connect a third cable being the ground in a standard electrical wiring? Or better still what's the difference between the neutral and the earth?
Ans: I used to think electricity was like water, where you turn on a faucet, and the electricity gets used up, like watering a houseplant, and that “ground” was like water soaking into the ground.
That's not at all how it works. And I'm going to write this for the others who also think this is how it works.
(I believed this well into adulthood, so don't shame. I'm building robots with RasPi and Arduino now.)
First, the electricity makes a full loop - it comes from the power plant, through the wire into your house, through the wire into your thing doing something useful, then back through the wire to the wall, then back to the power plant. It never soaks into the ground. It never connects to the earth.
This is how it works for a battery too - it goes back into the battery. With a battery, the energy is going one direction (Direct Current or DC). With the electricity from the wall, the energy comes from the electricity wiggling back and forth (Alternating Current or AC) via the live wire. But it's always connecting back to the power plant at all times via the neutral wire completing the circut.
If you want to get fully technical, the power goes back into the transformer near your house mounted on a telephone pole. In that transformer, the electricity is changed from high voltage, which is easier to transport long distances, to lower voltage, which is safer for your house. It does this by going through a coil of wire which makes a magnetic field. The coil is aligned with another coil. When the magnetic field goes through the second coil, it makes electricity flow through the wire of the coil at a different voltage. So, technically, the electricity goes from power plant, to transformer, then back. The power in your house loops only to the transformer and back and is magically coupled to the power plant through the magnetic field between the two coils. So I'm simplifying the picture by considering one loop from power plant to your home and back, but it's more like a chain of loops that are coupled together. But when you turn something on, the power plant feels the load directly.)
So what is “neutral” and what is “earth” or “ground”?
Neutral must always connect back to the power plant. All electricity connects back to the power plant. Neutral and hot are the wires that do that.
If you touch them, the electricity might want to flow through you. It will always flow from wire, through you, and out to a way it can connect back to the power plant. This can be through anything at all. But by tying the neutral to the ground wire and tying the ground wire to the metal housing for the outlet and conduit, this makes a path back to the power plant really close and handy, rather than just running through other things randomly that draw a lot of current.
There's a grounding rod pounded into the ground for every house. This isn't to drain away electricity back to earth like water. This provides a pathway through the ground back to the power plant. Again, this is to provide a safe return as short as possible for any stray electricity to get back to the power plant. If it can't get back through neutral, it can get back through the ground.
Now, a GFCI circuit looks at the electricity going through the hot wire and going through the neutral wire, and if they're not equal, that means electricity is going another route, and it then disconnects power to the wires. This is protection where water could provide that extra path for the electricity - in your bathroom, kitchen, or outside.
This is the answer to your question: neutral provides a direct path for hot back to the power plant. Ground is a secondary path, that connects all the nearby metal parts back to neutral, so stray electricity goes directly back to neutral instead of through whatever random path it can find. It's not meant to carry electricity. It's meant as a safety.
This is very different from a circuit breaker. What that looks for is too much electricity going from hot to neutral (or hot through ground - it can't tell.) If too much is drawn, then it disconnects. These two are very different in how they function and what they look for. (It took me a while to understand this, and it's related to the difference between neutral and ground.)
(The term “ground” is used in electronics in a way that perpetuated for me this belief that electricity always flowed back into the Earth. “Return” would have been a much better term.)
Electricity is less like water out of a spigot and more like hydraulics, where the fluid always runs through a loop, and parts function by using the force of the flow of that liquid. But hydraulics is not commonly understood by everyone, so is less useful of an analogy. But water how it's experienced by people everyday is misleading in a different way.
