Why the earth is zero potential?

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    Earth Potential Zero
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Discussion Overview

The discussion revolves around the concept of why the Earth is considered to be at zero electrical potential, particularly in the context of AC power systems. Participants explore various aspects of electrical potential, grounding, and the implications of using Earth as a reference point.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Mathematical reasoning

Main Points Raised

  • Some participants suggest that the Earth is chosen as a zero potential point for convenience, as potential differences are what matter in electrical systems.
  • Others argue that the Earth's potential is relatively stable and does not change significantly with the addition of charge, except in rare cases.
  • One participant notes that electrical potential is defined in terms of differences, and there is no absolute definition of potential at a single point.
  • Some participants express confusion about the concept of zero potential and question the properties that allow the Earth to be considered as such.
  • It is mentioned that ground potential can vary due to environmental factors like lightning strikes and magnetic storms, leading to practical issues in electrical systems.
  • Several participants emphasize that potential is relative, and any point can be chosen as a reference for measuring voltage.
  • There are discussions about the implications of grounding in AC power systems and how it is not a magical state but a practical choice made by power companies.
  • Some participants challenge the understanding of parallel resistance and its relation to grounding, indicating a need for further clarification on basic electrical principles.

Areas of Agreement / Disagreement

Participants generally agree that the Earth is used as a zero potential reference for convenience, but there is no consensus on the implications of this choice or the underlying properties that justify it. Multiple competing views and uncertainties remain regarding the nature of electrical potential and grounding.

Contextual Notes

Some participants express confusion about basic electrical concepts, indicating a potential gap in understanding foundational principles such as resistance and potential differences. There are also references to practical issues in grounding that highlight the variability of ground potential.

  • #31
NoTime, Integral?
NoTime: You want to say that the Earth have no resistance to current?
Integral: You say that everyone can manipulate with the potential of the earth? And If so how?
 
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  • #32
PLEASE STATE YOUR QUESTION IN A CLEAR AND CONCISE MANNER>


The power company sets Earth ground as a reference point. They do NOT manipulate it they call it zero and measure the produced voltage with respect to it. Your home wiring is the same.
 
  • #33
I would just like to point out that although most people correctly state that the Earth is assigned a zero potential for convenience, there are real consequences.

Electrical systems of both ships at sea and spacecraft require special considerations. Working on electrical systems on a metal ship that is in intimate contact with ground requires care, and maintaining electrical 'coherence' between the space station and the space shuttle as the shuttle moves from the Earth into orbit is not trivial.
 
  • #34
Why Zero, Simply because its under our feet and its convenient. The Earth has a magnetic field this effects Electrical equipment and conductors around us, but as how to define it as Zero simply Joining to Disimular Conductors together makes them Equal or Zero potential. Same theory as Farendays Cage, you're in the potential Zone so you will not get an electric shock. Step out of this zero potential and your toast. Electricity wants a simple way to Earth and by Earth we mean Zero, become that Zero and it will simply ignore you. Correct me if I am wrong but that's generally how it works.
 
  • #35
Daz87uk said:
Why Zero, Simply because its under our feet and its convenient. The Earth has a magnetic field this effects Electrical equipment and conductors around us, but as how to define it as Zero simply Joining to Disimular Conductors together makes them Equal or Zero potential. Same theory as Farendays Cage, you're in the potential Zone so you will not get an electric shock. Step out of this zero potential and your toast. Electricity wants a simple way to Earth and by Earth we mean Zero, become that Zero and it will simply ignore you. Correct me if I am wrong but that's generally how it works.

also Earth is not in itself Zero it has Resistance it can be used as a conductor. but by wiring things so "earth wires" go to ground (Soil) our electrical conductors equilize with the Ground creating a Zero potential or a place where live connections can fault and go directly to Earth instead of the unlucky guys hand. or basically it just wants to return with little resistance as possiable. (dont get in its way lol)

sorry this is the best i can explain as I am still learning Electrical Theory myself. :)
 

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