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

Stephen Offiler soffiler at gmail.com
Tue Oct 7 07:06:48 PDT 2008


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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>>> > >
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>>>
>>>
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