[AT] While we're on the subject of generators

Stephen Offiler soffiler at gmail.com
Tue Oct 7 08:31:25 PDT 2008


On Tue, Oct 7, 2008 at 10:24 AM, charlie hill
<charliehill at embarqmail.com> wrote:

> Steve that is the confusing part of it to me.  Knowing that the neutral
> carries current how can it be tied to the ground without 1) grounding out
> the circuit the neutral is carring current for...

Grounding out, you say?  Neutral should be at 0 volts.  I suppose I
can say it's SUPPOSED to be grounded out. You make sure it's there, at
0 volts, by connecting it to Earth.  The Hot lead swings positive and
negative with respect to the Neutral.  Electricity is all relative.
Because it's relative,  you have to give it a solid, known reference
by tying it down (at ONE point only!) to Earth.

>... or 2) energizing the ground
> circuit?

Energizing, you say?  We've tied both "neutral" and "ground" (just
names) to Earth (the real deal).  So they are now both at 0 volts.
Neutral has current, yes, but at 0 volts it has no energy (amps times
volts equals watts).


> To me it's like hooking your potable water and grey water piping together
> and saying the potable water is not contaminated.  Heck with the plumbing
> example you could at least put a check valve/backflow preventer in the
> circuit.  I've never seen a diode between the neutral and the ground in a
> 200 AMP panel.  I know the example is rediculous.  I'm just trying to point
> out how confusing it is to me.
>
> Charlie
> ----- Original Message -----
> From: "Stephen Offiler" <soffiler at gmail.com>
> To: "Antique tractor email discussion group" <at at lists.antique-tractor.com>
> Sent: Tuesday, October 07, 2008 10:06 AM
> Subject: Re: [AT] While we're on the subject of generators
>
>
>> It goes something like this:  the bare copper ground wires that
>> connect to the third prong of US receptacles are there specifically to
>> protect the metal chassis of appliances.  This grounding system has
>> two basic requirements:  one, it must tie to earth to ensure it
>> remains at 0 volts potential; and two, it must not normally carry any
>> current.
>>
>> The neutral conductor in an AC system, on the other hand, shares only
>> one of those two requirements.  It too must remain at 0 volts
>> potential.  Since the neutrual and ground share this potential, they
>> can be (should be...must be) tied together.  HOWEVER.  The big
>> difference is that the neutral conductor normally carries current and
>> the ground does not.  If you were to tie neutral and ground together
>> in multiple places, that puts them wired in parallel and they'll
>> naturally share current loads.  BAD.  By tying them together at one
>> and only one point, you are ensured they have the same potential
>> (which is zero volts once you connect to the stakes in the ground) and
>> you are ensured you are not creating parallel current paths.
>>
>> Steve O.
>>
>>
>> On Mon, Oct 6, 2008 at 8:26 PM, charlie hill <charliehill at embarqmail.com>
>> wrote:
>>> I'm no electrician.  Have trouble dealing with stuff I can't see.  LOL.
>>> This whole thing with  grounds and neutrals just doesn't make sense to
>>> me.
>>> It seems to me like 120V should be 1 phase and a neutral, 240V should be
>>> both phases and a neutral and the grounds for any or all of them should
>>> be
>>> isolated from the rest of the system.  I don't even want to think about 3
>>> phase.
>>>
>>> This is one of the great mysteries of my life.  I guess I should go to
>>> school on it or at least buy some books or something and learn to make
>>> sense
>>> of it all.  I'm not one bit more confused by quantum mechanics and string
>>> theory than I am by house wiring.  When it comes to any of the above I'm
>>> like a dog chasing an automobile.  If he ever catches it he won't be able
>>> to
>>> drive it.  I can at least wire up simple stuff but I don't understand why
>>> it
>>> works like it does.
>>>
>>> Charlie
>>> ----- Original Message -----
>>> From: "Larry Goss" <rlgoss at insightbb.com>
>>> To: "Antique tractor email discussion group"
>>> <at at lists.antique-tractor.com>
>>> Sent: Monday, October 06, 2008 8:09 PM
>>> Subject: Re: [AT] While we're on the subject of generators
>>>
>>>
>>>> Exactly, Bruce.  As a result, when I wired my new shop, I hooked them
>>>> all
>>>> together on the same buss.  That was a No-No, and the inspector told me
>>>> so.  I complained that I looked for a box that had the separate buss in
>>>> it
>>>> and there weren't any.  He then proceeded to tell me the busses are in a
>>>> little box on the shelf with a separate price tag on them.  So I
>>>> searched
>>>> at Home Depot and found the things hidden on a shelf about waist high,
>>>> bought one, installed it with the grounding screw I had used for
>>>> something
>>>> else, and went to the trouble of separating all the neutrals from the
>>>> grounds so I could hook them all back up together again.  It's a Royal
>>>> Pain, but that's the way the code is written.
>>>>
>>>> Larry
>>>>
>>>>
>>>> ----- Original Message -----
>>>> From: Bruce Moden <brucemoden at yahoo.com>
>>>> Date: Monday, October 6, 2008 14:43
>>>> Subject: Re: [AT] While we're on the subject of generators
>>>> To: Antique tractor email discussion group
>>>> <at at lists.antique-tractor.com>
>>>>
>>>>> Note:
>>>>> In other electrical applications "neutral' is synonymous with
>>>>> "ground" if you check your panel box you will note that all the
>>>>> white wires (neutral) in your household wiring go to a bar of
>>>>> similar wires and all the ground wires go to a bar for bare
>>>>> copper (ground) wires and if you check further the two are
>>>>> connected.  This has been my experience over the years- but
>>>>> is free information and may be worth the price paid!
>>>>> Pharmr
>>>>>
>>>>>
>>>>> --- On Mon, 10/6/08, Cecil Bearden <crbearden at copper.net> wrote:
>>>>>
>>>>> > From: Cecil Bearden <crbearden at copper.net>
>>>>> > Subject: Re: [AT] While we're on the subject of generators
>>>>> > To: "Antique tractor email discussion group"
>>>>> <at at lists.antique-tractor.com>
>>>>> > Date: Monday, October 6, 2008, 7:50 AM
>>>>> > When you have it running, I am connect yourvoltmeter from
>>>>> > each hot leg
>>>>> > to the common.  Then connect from this to the generator
>>>>> > frame.  If there
>>>>> > is no voltage, then this is the neutral for sure.  The
>>>>> > common should be
>>>>> > your neutral.  I say should be as I have had some
>>>>> > interesting things
>>>>> > happen.  ost a message on the old generators forum at
>>>>> > smokstak.com  ther
>>>>> > are some Onan technicians there who work in the areas that
>>>>> > have to run
>>>>> > on generators all the time....
>>>>> >
>>>>> > Cecil in OKla
>>>>> >
>>>>> > Chris C wrote:
>>>>> > >
>>>>> > >   Can anyone here help me out with an older Onan
>>>>> > Generator?  I have a 12KW DJC generator that I am wiring to
>>>>> > my panel as a backup generator.  I know that the generator
>>>>> > need to get neutral bonded to get along with the GFI's
>>>>> > in the house,  but I can't find a wiring diagram to tell
>>>>> > me for sure what the neutral is.  And I have found the local
>>>>> > Onan folks completely useless as they seem to believe that I
>>>>> > will sue them if things go bad..  Anyone have some Onan
>>>>> > info?
>>>>> > >
>>>>> > >           Chris
>>>>> > >
>>>>> > >
>>>>> > >
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