The following is a quote from PM magazine. "My electricity guru friend Dale Watterson, of Madison Gas and Electric Company, kindly corrected a point in my February column, "Grounding". I wrote that neutral electricity goes back to the power plant. He says that, no, the neutral leg goes to ground. Dale assures us that there's no problem except for farmers whose cows get a hoof-to-mouth transmission and don't like it" End Quote. Now I'm no "guru", but I was allways taught that the neutral current does travel back to the source of power a.k.a. the power plant. What do some of you gurus think?
Neutral current
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crossman
Senior Member
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- Southeast Texas
Re: Neutral current
That is pretty interesting (funny).
One point of contention that is never considered by the "gurus" is that we are dealing with AC voltage and current....
sometimes electricity takes the least resistive path FROM ground!
caution: ^tongue in cheek^ and not about the FROM part
[ March 21, 2005, 02:08 PM: Message edited by: crossman ]
That is pretty interesting (funny).
One point of contention that is never considered by the "gurus" is that we are dealing with AC voltage and current....
sometimes electricity takes the least resistive path FROM ground!
caution: ^tongue in cheek^ and not about the FROM part
[ March 21, 2005, 02:08 PM: Message edited by: crossman ]
physis
Senior Member
Re: Neutral current
We had a thread here recently where the point came up that the electrons used at an electrical service don't go back to the electric company because they stay on one side of the transformer. If current is the rate of moving charges, do the charges of the neutral current cross between the primary and secondary transformer windings?
For the neutral current return path to the transformer there are usually two. The neutral conductor and the earth. The power company's transformer neutral is grounded at one point and the service is grounded at another point. So the neutral current travels over both paths back to the transformer. The earth path is a pretty high impedance and the neutral conductor is pretty low so most of the current is returning over the neutral conductor.
We had a thread here recently where the point came up that the electrons used at an electrical service don't go back to the electric company because they stay on one side of the transformer. If current is the rate of moving charges, do the charges of the neutral current cross between the primary and secondary transformer windings?
For the neutral current return path to the transformer there are usually two. The neutral conductor and the earth. The power company's transformer neutral is grounded at one point and the service is grounded at another point. So the neutral current travels over both paths back to the transformer. The earth path is a pretty high impedance and the neutral conductor is pretty low so most of the current is returning over the neutral conductor.
physis
Senior Member
Re: Neutral current
I just realized that your power company friend is talking about a transmition method that uses earth as a neutral conductor. Charlie E. will, I'm sure, will want to comment on that.
Edit: The earth isn't always used as a conductor for transmission.
[ March 21, 2005, 03:41 PM: Message edited by: physis ]
I just realized that your power company friend is talking about a transmition method that uses earth as a neutral conductor. Charlie E. will, I'm sure, will want to comment on that.
Edit: The earth isn't always used as a conductor for transmission.
[ March 21, 2005, 03:41 PM: Message edited by: physis ]
crossman
Senior Member
- Location
- Southeast Texas
Re: Neutral current
corollary
half the time, neutral current comes FROM the power plant
touch a 120/208 hot conductor and a ground rod... half the time the electrons are flowing from the ground rod through your body to the hot
it is amazing that the whole thing doesn't blow up
corollary
half the time, neutral current comes FROM the power plant
touch a 120/208 hot conductor and a ground rod... half the time the electrons are flowing from the ground rod through your body to the hot
it is amazing that the whole thing doesn't blow up
crossman
Senior Member
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- Southeast Texas
Re: Neutral current
Just one of my "pet peeves" on the "electricity always takes the least resistive path to ground" old wives tale.
We've all heard that, and the myth is still circulating... and young apprentices will bring it up.
so I say "but it is AC current, right, it flows both directions, right?"
they agree
So then I say "then a bare-footed person standing in a water puddle who is touching a hot wire actually has current flowing from the earth back to the hot wire half of the time?"
"Er... uh? I guess so...
"well then how come the whole thing doesn't short out when you ground the neutral to earth?"
Just one of my "pet peeves" on the "electricity always takes the least resistive path to ground" old wives tale.
We've all heard that, and the myth is still circulating... and young apprentices will bring it up.
so I say "but it is AC current, right, it flows both directions, right?"
they agree
So then I say "then a bare-footed person standing in a water puddle who is touching a hot wire actually has current flowing from the earth back to the hot wire half of the time?"
"Er... uh? I guess so...
"well then how come the whole thing doesn't short out when you ground the neutral to earth?"
crossman
Senior Member
- Location
- Southeast Texas
Re: Neutral current
I suppose another wives tale would be "electricity always takes the least resistive path to the hot"
I suppose another wives tale would be "electricity always takes the least resistive path to the hot"
charlie
Senior Member
- Location
- Indianapolis
Re: Neutral current
Dale Watterson is correct if you are talking about a transmission line. Each set of transformers provides a separate set of moving electrons that go back and forth to the source using all available paths. This statement applies to standard power transformers.
I am guessing that dale was answering so that his audience would understand his answer and not to be technically correct.
Dale Watterson is correct if you are talking about a transmission line. Each set of transformers provides a separate set of moving electrons that go back and forth to the source using all available paths. This statement applies to standard power transformers.
I am guessing that dale was answering so that his audience would understand his answer and not to be technically correct.
charlie
Senior Member
- Location
- Indianapolis
Re: Neutral current
Actually Sam, I have never done transmission work. I do know that we only use three phases and then a static shield for lightning protection. Also, I don't know what the transformer configurations are in the substation where we go from 345 kV to 138 kV. The distribution substations go from 138 kV in a delta configuration (I think) to 13.2 kV in a wye configuration.
With all that said, I still didn't answer your question with any certainty.
Actually Sam, I have never done transmission work. I do know that we only use three phases and then a static shield for lightning protection. Also, I don't know what the transformer configurations are in the substation where we go from 345 kV to 138 kV. The distribution substations go from 138 kV in a delta configuration (I think) to 13.2 kV in a wye configuration.
With all that said, I still didn't answer your question with any certainty.
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