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According to Benjamin Franklin, current flow from +ve to -ve terminal. But after Joseph Thomson's discovery it was conceived that although current flows from +ve to -ve electrons flow from -ve to +ve terminal.

Now w.r.t. Alternating Current neutral provides return path, so why touching metal of neutral doesn't give a shock?

RinkyPinku
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user_1234
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    Please don't touch the neutral. – Nick Alexeev Mar 27 '15 at 06:46
  • By convention, current flows from positive voltage to negative voltage. On a forum like this, EVERYONE knows that the charge carriers in copper wire are electrons and that they are negatively charged, and flow toward the positive voltage. But current flows in the direction opposite of the electron flow. You get shocked when current flows through your body. Often, the neutral wire is very close to ground potential, and you are too. So, often, there is not enough voltage to give you a shock. But Nick is right. Don't touch it. Sometimes a wire you THINK is neutral might be hot. – user57037 Mar 27 '15 at 06:52
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    @mkeith Even a properly connected neutral may have some potential. If there is a current through neutral, the end of the neutral can have a potential with respect to earth (tens of volts in some cases). – Nick Alexeev Mar 27 '15 at 06:59
  • Yes, agreed. I would advise against touching neutral unless the power has been shut off. But I was running out of space in my comment and couldn't get that in there. Although, I should ad that 10's of Volts is not enough to cause a noticeable shock if you touch it with your hand. – user57037 Mar 27 '15 at 07:19
  • I rejected an edit to this post because it added phrases like "electron flow" that the original poster did not include - therefore cannot be assumed as knowledge. – David Mar 30 '15 at 06:54
  • Talking aboit conventional flow when discussing predominantly ac is very misleading. – RichieHH Oct 07 '19 at 07:22

2 Answers2

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The main points to note is that the neutral and ground(earth) wire at homes are at zero potential. But the "live" has a fairly high potential. So when you touch a "live" wire with you being in contact with the earth, (say standing on the floor bare footed) a voltage of 240V/120V (Indian Domestic Voltage/US Domestic Voltage) between live and earth, and a fairly high current from the Distributor is high enough to get you a shock as the incoming current tries to flow from live via you to earth(which is having low impedance as current has a tendency of flowing in through low resistance path). (Touching a "live" wire and being insulated from earth, say you are standing on the floor with well electrically insulated shoes you wont get a shock because the voltage between live and you becomes zero).

Touching a neutral wire and standing on floor say bare footed, remember the voltage between them is zero(potential diff is zero) because both neutral and earth are at zero potential. So even the current returns through neutral (only from a connected load that completes the current flow circuit) you touching the neutral with a 0V cant get you a shock.

But its not safe to touch neutral wire!

  1. It is possible that the path to ground on neutral is not very good. When load is connected to the plug point the neutral may not always be at zero potential. Some voltage between earth and neutral(at a high potential) can give you a shock. For instance when I take voltage reading across neutral and earth at my home plug point I get reading between 5-10V. If this becomes high of about 50V or more and you touch neutral you will get a shock.

  2. It is common that wiring is done incorrectly. It is possible that "live" is wired to neutral and vice versa, many items of electrical equipment will work with live and neutral swapped.

DerStrom8
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techloris_109
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    This is an extremely dangerous answer. The neutral is at zero potential IF AND ONLY IF everything is working properly. There is always a chance that something has gone wrong and the neutral is not at zero potential. Until you know with confidence that the wire is at 0V, don't touch it. (Your edit seems to answer this - thanks.) – Greg d'Eon Jun 12 '15 at 14:52
  • well my answer needs to add @Greg d'Eon point too. Read that somewhere. thanks. Greg could you specify in detail at what all conditions does the neutral be at a non zero potential. Know that neutral is grounded at Distributor equipment and earth grounded through earth electrode then why does it change potentail from zero? – techloris_109 Jun 12 '15 at 21:56
  • take a look at http://electronics.stackexchange.com/a/76731/49251 – Greg d'Eon Jun 12 '15 at 21:58
  • I edited this to add warning about not touching neutral. So I think it's not dangerous now. I expanded explanation why not: 1. bad path to ground(already in answer) 2. incorrect wiring. – gaoithe Oct 25 '16 at 11:14
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    Surely ac current means both wires are hot? The voltage is alternating around 0 or ground... – RichieHH Oct 07 '19 at 07:23
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Neutrals are grounded. If not at your home, they are on substation, on poles etc. As you are supposed to know, it only flows current where exists a difference of potential (voltage), according to Ohm's Law. When you touch a wire, you act like a way to earth, closing a circuit. Since the neutral is at the same potential than the earth (or very next), the current that flows through you is nearly 0. If I'm not mistaken, a dry body will not get shock from below 50V AC which on normal circumstances is very improbably that you will get this voltage between neutral and ground. Additionally, it is not impossible. A fault on your system can leads to high voltages between neutral and ground, so please, never touch an energized circuit.

Pedro Quadros
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