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Dean Hoffman[_12_] Dean Hoffman[_12_] is offline
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Default What is the difference between ground and neutral from theperspective of the wall outlet working backward to the power company?

On 7/28/19 7:53 PM, Clare Snyder wrote:
On Sun, 28 Jul 2019 19:42:54 -0500, Dean Hoffman
wrote:

On 7/28/19 6:01 PM, Clare Snyder wrote:
On Sun, 28 Jul 2019 11:09:54 -0500, Dean Hoffman
wrote:

On 7/27/19 10:31 AM, Arlen G. Holder wrote:
From the US homeowner's perspective of working backward from a wall outlet
o What is the difference between ground and neutral in the US?

A friend is debugging why the washing machine metal case is hot only when
the water pipes are hooked up and water flowing through them when I tried
to explain to that homeowner over the phone the difference between ground
and neutral - where - I'm not sure I have it all figured out myself.

I'm going to point her to this answer on the net.

*Is this correct for ground?*
o It's the round hole in a 3-hole outlet
o It's usually a bare copper wire (or sometimes green).
o It's connected to the sub panel without any breaks whatsoever.
o From the sub panel it connects to the main panel sans any breaks.
o From the main panel it goes directly to the main inlet cold water pipe.
o From that main cold water inlet pipe, it goes into a stake in the ground.
o It should never carry current unless there is a problem somewhere.
o Therefore, the voltage from it to the ground should be zero.

*Is this correct for neutral?*
o It's the taller slot in the typical grounded US outlet box.
o It's the white insulated wire (when black or red is the hot wire).
o It's connected to the sub panel but it may have connections between.
o From the sub panel it connects to the main panel sans any breaks.
o From the main panel it goes directly to the power company input.
o Generally that power company input will be a power pole.
o Within a few power poles will be the step-down transformer.
o From that step-down transformer the neutral will go into the ground.
o Therefore, the voltage from the outlet neutral to ground should be close to 0

In a way, they're similar in that both the ground and neutral eventually go
directly into the ground - but they're different in that the neutral
carries current while the ground only carries current when something is
wrong.

This doesn't look quite right to me. Electricity tries to return
to its source
through all available routes, not to ground. You can have a lamp and
a tv running
on the same circuit, for example. Two lamps with incandescent bulbs of
different wattage will work on the same circuit.
Ground rods are for lightning protection. They won't do any real good
if there is a short to ground somewhere in the system.




I hope you hire an electrician when you have electrical problems, as
you do NOT understand electricity


I'm missing your point. What is it I don't get, specifically?

Try the math here yourself.
http://www.ohmslawcalculator.com/ohms-law-calculator
Pretend there is a short to the frame of some electrical device and
there are only the ground rods and the dirt to conduct electricity back
to the power company's transformers. No equipment ground.
Put the ground rods in series and each at 25 ohms resistance.
There won't be enough current flow to trip a typical breaker.


DUH!! That's why code REQUIRES a contiguous safety ground, bonded to
the neutral at the service panel.
I fix irrigation systems. Even the high leg of a center tap delta
shorting
to a system's frame would be about 8 amps flowing back to the transformer.
Fusing is usually at least 15 or twenty amps.


Which is why physical "safety grounds" are required.
I understand it doesn't really flow like water.

Before I point the homeowner to this thread, can you clarify or fix
mistakes in my understanding of the difference between neutral & ground?