Date:         Wed, 19 Apr 2006 22:23:24 -0400
Reply-To:     Edward Maglott <emaglott@BUNCOMBE.MAIN.NC.US>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Edward Maglott <emaglott@BUNCOMBE.MAIN.NC.US>
Subject:      Re: battery-inverter-charger-battery loop
In-Reply-To:  <002a01c66403$46302e40$6400a8c0@masterpc>
Content-Type: text/plain; charset="us-ascii"; format=flowed

Yeah that does happen more than I like to think about.  In my 80 yr old
house, I had an outlet fail so that ground became hot for that whole
circuit.  When I get to the CG I use one of those little plug in circuit
testers to make sure the power is on and good, at the site I choose.

I plugged that into my inverter today and it said "open ground."  I opened
the inverter, and the ground does go to the inverter case, and is not
common with the neutral pole.  I read with a meter, and got about 40 volts
between ground and neutral.  I did a little test of wiring the ground and
neutral into the van's AC system and left hot disconnected.  As i expected,
I was seeing that 40 volts throughout the system including the male plug on
the outside of the van.

I have a beefy DPDT switch I was going to use for this project, but I was
hoping to use one pole to turn the inverter on when I switch to it.  Now
where is that drawing board...

Edward

At 06:47 PM 4/19/2006, you wrote:
>Just imagine the first time you plug into a campground with a receptacle
>that is wired wrong. Unless that "neutral" is bonded to a ground point,
>it is not a neutral. When switching between different power sources, the
>switch must disconnect all ungrounded source conductors. You need a
>double pole, double throw switch, (DPDT). Transfer switches for this
>task are available and not that expensive. Of course, proper use of cord
>an plug can accomplish the same goal.
>
>Dennis
>
>
>-----Original Message-----
>From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf
>Of John Bange
>Sent: Wednesday, April 19, 2006 11:14 AM
>To: vanagon@GERRY.VANAGON.COM
>Subject: Re: battery-inverter-charger-battery loop
>
> > Shouldn't I just be able to switch the hot side of the 110v circuit?
> >
>Just switching the hot side and leaving the neutral shared should be
>fine.
>When plugged into shore power the inverter hot should have no potential
>to
>shore neutral, and shore hot should have no potential to the inverter
>neutral. I've heard about some people having weird inverter gremlins due
>to
>chassis ground being bonded to shore ground and inverter neutral being
>(for
>some reason) connected to chassis ground, but I suspect the trouble
>there
>was due to installer error. I've run a 1500W "mechanical inverter"
>(really a
>12V motor spinning a 120V generator) for years with a nothing-special
>Leviton 3-way switch to switch to shore power on the hot leg.
>
>--
>John Bange
>'90 Vanagon - "Geldsauger"