Why don't I get shocks on neutral wire?

  • Context: High School 
  • Thread starter Thread starter justwild
  • Start date Start date
  • Tags Tags
    Neutral Wire
Click For Summary

Discussion Overview

The discussion revolves around the reasons why individuals do not experience electric shocks from the neutral wire in household AC wiring systems. Participants explore concepts related to AC current, household wiring configurations, and grounding practices across different regions.

Discussion Character

  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant notes that the AC current changes direction periodically and questions why the neutral wire does not produce a shock, suggesting a difference in household wiring.
  • Another participant explains that the neutral wire is termed "neutral" because it does not carry AC current like the live wire does.
  • A participant shares measurements indicating a voltage difference between neutral and ground, citing the US National Electrical Code's specifications for maximum allowable voltages between these points.
  • There is a question raised about why the maximum voltage difference between neutral and ground is higher for 240V circuits compared to 120V circuits, seeking clarification on the underlying electrical principles.
  • A participant mentions that in some countries, such as Australia and New Zealand, the neutral line is grounded at the household fuse or meter panel, implying a difference in safety practices and wiring standards.

Areas of Agreement / Disagreement

Participants express varying views on the nature of the neutral wire and its grounding practices, indicating that multiple competing perspectives exist regarding household wiring and electrical safety. The discussion remains unresolved on several technical points.

Contextual Notes

Participants reference specific voltage measurements and electrical codes, highlighting potential regional differences in wiring practices and safety standards. There are unresolved questions regarding the implications of these differences on electrical safety.

Who May Find This Useful

This discussion may be of interest to individuals studying electrical engineering, electricians, or those curious about household wiring and electrical safety standards in different countries.

justwild
Messages
52
Reaction score
0
Why don't I get shocks on neutral wire?

In my textbook the AC current is defined to be one which changes its direction periodically.
So according to the text both the wires of the AC supply should give you shock, but I felt the real shock when I observed that the neutral wiring didn't shook me!

So what is different in household wiring?
 
Physics news on Phys.org


The neutral wire is called neutral because it is, well, neutral. The other one has AC, this gives AC between the two cables.
 


Link to diagram of household wiring (USA style):

hsehld.htm

At my home, depending on location, I measure up to 1/2 volt difference between "neutral" and "ground", due to issues like impedance. The US National Electrical Code translates into a max of 3.6 volts between neutral and ground for 120 volt outlet, and 6.6 volts for 240 volt outlet.

Going back to that diagram in hsehld.htm, at my area, that transformer has a single phase 6900 volt line and ground on the input side of the transformer, and a 240 volt transformer with grounded center tap (for 120 volt) output.

"Stray voltage" can be an issue for locations like dairy farms. Wiki article:

http://en.wikipedia.org/wiki/Stray_voltage
 
Last edited:


rcgldr said:
Link to diagram of household wiring (USA style):
The US National Electrical Code translates into a max of 3.6 volts between neutral and ground for 120 volt outlet, and 6.6 volts for 240 volt outlet.

Why the higher limit between neutral and ground for a household 240v circuit than 120v? The 240v circuit is two 120v circuits on opposite phases, so shouldn't be able to pull anything further away from ground than a 120v circuit? Just wondering... I'm away from my copy of the code right now.
 


So what is different in household wiring?

In Australia, New Zealand and maybe a few other countries
the neutral line is grounded at the household fuse/meter panel

Dave
 

Similar threads

High School Is it dangerous to touch neutral wire?
  • · Replies 7 ·
Replies
7
Views
22K
Undergrad Neutral wire in electric power distribution between substations
  • · Replies 13 ·
Replies
13
Views
4K
Graduate Skin effect and electric shock question
  • · Replies 2 ·
Replies
2
Views
2K
Graduate B field around a wire, single wire electromagnet
  • · Replies 2 ·
Replies
2
Views
2K
AC Current versus AC Voltage on the Neutral Wire of AC Mains
  • · Replies 5 ·
Replies
5
Views
2K
High School How is surface charge accumulated?
  • · Replies 36 ·
2
Replies
36
Views
7K
Undergrad Ground vs Neutral: Inside the House or Lab - Explained
  • · Replies 17 ·
Replies
17
Views
6K
High School Can high voltage static electricity cause a shock through a power cord?
  • · Replies 6 ·
Replies
6
Views
3K
Undergrad AC Electric Neutral Current Flow
  • · Replies 2 ·
Replies
2
Views
4K
High School AC Circuits: Voltage Changes and Neutral Becoming Live?
  • · Replies 7 ·
Replies
7
Views
10K