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Generator set up ideas wanted
"All this talk of backfeeding the utility (and presumably killing a lineman) is really not relevant here. Backfeeding is not possible even if neutral remains connected in the transfer switch (as is sometimes required) if the hot lines are switched (as required in all situations) and neutral is grounded at one location only (service entrance)."
HORSE ........ APPLES!!!
If you take 4 metal rods and drive them in the ground in a wide circle, then measure between them you will see a voltage potential between, them, small, but measureable. Anytime you have multiple paths to earth you will have a measureable voltage potential between them, this is EMF induced, the further it is between two points, the more the potential, this is why the NEC requires so many ground rods in the grid. When you introduce an inductive source like a genset, then use the ground wire as a current carrying conductor, you just amplify the problem.
"As a minor asside on this issue I challenge any readers out there to demonstrate how a circuit could be completed that could injure or kill a lineman when the neutral line remains connected to the utility and connections are made according to code."
On March 8, 2005 a dog was electrocuted while lifting it's leg on a metal lamp-post in Maryland. The cause was stray voltage, after looking into the situation the utility offered the family $200k, they are demanding $740k., the matter is before the courts.
A lady was electrocuted while walking her dog in NYC when she stepped on a ConEd manhole cover. The cause was stray voltage, after looking into the situation ConEd discovered that this was a situation that affects 0.05% of it's manhole covers, in NYC that amounts to 130 manhole covers capable of killing a person.
"It's a technical issue and hard to understand."
Apparently it is.
Best of luck.
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Generator set up ideas wanted
A quick thought would seem that turning off the main breaker would make the power lines safe with a generator powering the circuits of the house.
The power company could not explain nor find why there is about 17 volts (the last I heard) between the ground wire and the ground rod at our Church. They said there was a voltage leak somewhere in the area feeding it.
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Generator set up ideas wanted
"A quick thought would seem that turning off the main breaker would make the power lines safe with a generator powering the circuits of the house."
No, that's exactly my point, the neutral & ground are permanently bonded together, and even bypass your meter that way. As long as there is electricity in the house, you are creating a VOLTAGE POTENTIAL outside of your house in the grid as well unless you disconnect the ground wire between the grid and your house, leaving of course, the ground rod as part of your houses circuit.
"....there is about 17 volts (the last I heard) between the ground wire and the ground rod at our Church."
That's exactly the problem. You can have voltage potential in a supposedly 'dead' line.
Everybody seeems to forget one small detail, the ground & the neutral in your house are bonded together, and the neutral is a load carrying 'leg' of any circuit, therefore there is a (up to) 220 volt potential in your ground circuit.
Best of luck.
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Generator set up ideas wanted
Dec. 8, 2005
Grinder,
It sounds as if this is for a backup to your house in
power outages. I will attempt about any project EXCEPT
electrical stuff like this. I had a 7KW Generac installed
by a dealer and run it off of LP. I use LP for my heat
also, so it was an easy decision. You really need to know
your electrical stuff to do this or you can really cause
problems. I believe at the time (2 years ago), it was about
$3200 installed. I live in the 'boonies' and my elderly
father is now living with me, so it was well worth it.
Sometimes, it is not worth skimping to save a few bucks.
Let the experts do it.
doc
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Interesting discussion, however I’m having trouble sorting out the various positions that folks are taking … maybe it doesn’t matter.
However it is a fact that in order for electrons to flow there needs to be a path. And sometimes humans are in the path and bad things happen.
Consider this, birds, squirrels and other little varmints climb power poles and sit on high voltage lines all the time. But as long as the impedance between them and the second conductor is high enough nothing bad happens. The key here is that the total circuit impedance between the animal sitting on the conductor at point A relative to a point B of the second conductor remain relatively high. If the magnitude of this impedance drops low enough such that a few ma’s were to cross the little buggers heart he may be toast.
So Murf, what exactly is your claim?
Are you claiming that there is a circuit path of consequence given the fact that one has disconnected the high side power but left a connection between the gnd/neut system of the house and generator? Or are you merely arguing that a potential exists between the house and the public feed, i.e., service transformer?
It would be helpful if you would provide a schematic to help illustrate your point. Something similar to the one in the link that Ann provided is adequate.
Dave
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Generator set up ideas wanted
Murf you certainly have an enormous amount of conviction here. I said I would not reply but I can't resist.
Murf, in the following quote:
"When you introduce an inductive source like a genset, then use the ground wire as a current carrying conductor, you just amplify the problem."
Using the web link I posted, would you be so kind as to indicate the number of the CODE COMPLIANT diagram in which, as you suggest, the ground wire is being used a current carrying conductor. I don't see which one that is?
And in this excerpt:
"No, that's exactly my point, the neutral & ground are permanently bonded together, and even bypass your meter that way. As long as there is electricity in the house, you are creating a VOLTAGE POTENTIAL outside of your house in the grid as well unless you disconnect the ground wire between the grid and your house, leaving of course, the ground rod as part of your houses circuit."
It would help me understand if you could simply illustrate the completed circuit that could electrify our "many times dead already" lineman. For example: Hot (L1) to load to neutral to lineman to neutral to powerstation to L1 = completed circuit = dead lineman or as the case may be dead linechick. Could you also indicate between which two specific entities this "VOLTAGE POTENTIAL outside of your house" exists. For examle: a 220V potential between utility neutral and utility L1. Please indicate which code compliant diagram (in the web link I posted) you think the generator would produce the voltage potential in the utility lines you keep refering to.
And in this quote:
"Everybody seeems to forget one small detail, the ground & the neutral in your house are bonded together, and the neutral is a load carrying 'leg' of any circuit, therefore there is a (up to) 220 volt potential in your ground circuit."
In this comment between which two specific entities are you indicating the 220V potential exists. For example a 220v potential between ground and L1 or between neutral and L1.
Many thanks
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Generator set up ideas wanted
091755
Thanks for your concern, I plan on having my electrician
do it.
I was just looking for set up ideas, fuel types,etc.
But I think we may need a seance with Thomas Edison.
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Generator set up ideas wanted
There was a thead a few days ago about sub panel in a pole barn. I quickly found it got warm with my thoughts not agreed with by another. Hey, that is a benefit of discussion. In that thread the person that took me to task said the neutral and ground are never bonded if memory is correct. Here Murf says they are. (They are bonded here also.) There is something I think is being forgotten...code...currently codes for all of the U.S. and Canada may be the same but a few years ago even in the U.S or within a state the code would vary. Since my post yesterday I spoke to a person with our local electric coop. He said most people here do not use transfer switches. He also said it is possible to have back feed on neutral. I understood he said it should not happen but can.
My advice...run large extension cords to applicances you need to run and then there is no possible back feed. I realize that is not easy for hard wired such as a furnace. Put a plug on it and outlet with the twist lock type and it will work. I think you will find the cost much less than the trasnfer switch and it's installation.
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Grinder, Thomas Edison sunk all his money into DC current production which ended up being a mistake. If you want a seance with the expert, you'll want to conjure up Nikola Tesla and his partner Westinghouse for AC expertise. The feud between Tesla and Edison is interesting reading. Edison went so far as to call electrocution being "Westinghoused." (link below).
Dave
Link:
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Ann, in every single one of the CODE COMPLIANT diagrams the neutral & ground are bonded at the main panel.
If in ANY of those diagrams, 1, 2, 5 & 6, and with the generator running, you put a meter between the neutral line outside the house, and the earth itself, you WILL measure a potential across those two points.
Further, if you were to run an extension cord out some distance from the house, and again measure between the neitral leg, and the earth, you might be surprised to see just how much potential voltage & current you would find.
"Using the web link I posted, would you be so kind as to indicate the number of the CODE COMPLIANT diagram in which, as you suggest, the ground wire is being used a current carrying conductor. "
Every one of them, the neutral wire in any house is a current carrying conductor, the AMOUNT of current is NORMALLY extremely low in the ground circuit though, since it takes the path of least resistance, the neutral leg.
Want proof, put on some heavy leathe gauntlets, top up your life insurance, disconnect the neutral wire from a 3 prong receptacle, then plug something in and see if you don't still have 120 volts and more than enough flow to power an appliance.
As was stated so well by jdcman "However it is a fact that in order for electrons to flow there needs to be a path. And sometimes humans are in the path and bad things happen."
The electricity takes the path of least resistance, but it does and will travel, if one path is the neutral leg of the grid, and a second path is a linesman or other unfortunate individual, "bad things happen.".
Ask any farmer with cattle, they are about 50 times more sensitive to voltage than humans, I've seen them stand in a circle around a water trough, not drinking, because of a few transient volts from a stock tank heater or some other source.
Best of luck.
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12-08-2005, 13:39 
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