AC Electric Neutral Current Flow

In summary, in an AC electrical circuit, the Neutral wire is connected to the ground at either the household or distribution point. The voltage between the Live and Neutral wires is what allows for the current to flow through the circuit. In some cases, such as in the UK, one of the power wires may also be connected to the ground for safety reasons.
  • #1
mjcguest
22
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AC Electric Neutral Current "Flow"

Hi everyone

Can someone point me in the right direction here please. Happy to do the digging, but so far I can't find anything that helps!

In an AC alternating-current electrical circuit, the Neutral wire is ultimately connected to "mother earth" / "big stake the ground" - sometimes at the household (e.g. UK), sometimes at a distribution point (e.g. europe). I've used "mother earth" as this is NOT a question about the "earth" wire you find in a plug...!

So... Into my simplistic circuit (let's say from the left) comes my Live 240v / 120v wire, goes into my appliance (toaster / light bulb), out from the right of the appliance comes a Neutral wire that somewhere way over to the right ends up buried 6 feet in the ground.

So far so good. The bit that is doing my noggin in, is the neutral line has a zero voltage. I can not get my head around the How & the Why?
- How can I have 240v going into a light bulb and 0v coming out?
- Why does the neutral need to be grounded if it's Zero volts (what part DOES it play in the circuit?)

I know I've picked up a wrong concept in here somewhere... any help in finding it would be most appreciated!

Thanks
Matt
 
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  • #2
Yes, the voltage is the concept that you picked somehow wrong.
It does not even make sense to say "240 V going into" and so on.
The voltage does not circulate or move through the circuit.

In order to have a current through your load you need to have a potential difference across this load. So one "end" of the load must have a higher voltage than the other.
The actual values associated with each end are quite arbitrary. May be 240 and 0 or 120 and -120 etc. It depends on the reference.
A common convention is to attribute zero to the ground or Earth potential, in problems with circuits.

The analogy with water flow was mentioned so many times...
 
  • #3
What nasu said.

How can I have 240v going into a light bulb and 0v coming out

I know people use the expression "you have 240V going into..." but it's best to think of is as..

Current goes through things.
Voltages appear across things.

The power station produces 240V between Live and Neutral. The load is connected to Live and Neutral so 240V appears across the load. Aside: At the risk of confusing you... Not all systems connect one of the power wires to earth. In the UK house builders use 110V power tools on building sites for safety reasons. A transformer is used to generate 110V from 240V. The transformer has two wires coming out. If you measure the voltage between them you will see 110V AC. However the transformer also has a centre tap which is connected to earth. So if you measure between either wire and Earth you see 55V AC. The power tools are connected between the two 55V lives so they get 110V AC. However Bob the Builder (who walks around with bare wet feet) will only get a 55V shock if he touches either wire. His feet are at earth, his hand at 55V. To get a 110V shock he would have to touch both wires which is unlikely.
 

FAQ: AC Electric Neutral Current Flow

What is AC electric neutral current flow?

AC electric neutral current flow refers to the flow of electrical current in an alternating current (AC) circuit. This type of current changes direction periodically, as opposed to direct current (DC) which flows in only one direction.

How does AC electric neutral current flow differ from DC electric current flow?

The main difference between AC and DC electric current flow is that AC current changes direction periodically, while DC current flows in only one direction. AC current is also typically used for long-distance power transmission, while DC current is used for smaller, more localized applications.

What is the purpose of a neutral wire in an AC electric circuit?

The neutral wire in an AC electric circuit is used to complete the circuit and provide a return path for the electrical current. It is typically connected to the ground and helps to balance the electrical load in the circuit.

How is AC electric neutral current flow measured?

AC electric neutral current flow is typically measured in amperes (A), which is a unit of electrical current. This measurement can be taken using a device called an ammeter, which is connected in series with the circuit to measure the amount of current flowing through it.

What are the potential dangers of AC electric neutral current flow?

AC electric neutral current flow can be dangerous if not properly managed. If the current is too high, it can cause electrical shocks, burns, and even death. It is important to use proper safety precautions and follow electrical codes and regulations when working with AC electric current.

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