Date:         Wed, 19 Apr 2006 18:20:30 -0700
Reply-To:     John Bange <jbange@GMAIL.COM>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         John Bange <jbange@GMAIL.COM>
Subject:      Re: battery-inverter-charger-battery loop
In-Reply-To:  <002a01c66403$46302e40$6400a8c0@masterpc>
Content-Type: text/plain; charset=ISO-8859-1

On 4/19/06, Dennis Haynes <dhaynes@optonline.net> 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.


I'm not sure what you're saying will happen in that case. Neutral on the
inverter is part of a closed-loop system-- not the same as the
neutral-to-ground of shore power. Given that one side of either supply pair
will be open due to the switch, only the opposite side will be a circuit.
Auxiliary power systems usually DON'T switch the neutral, but rather just
the hot conductors.

When switching between different power sources, the
> switch must disconnect all ungrounded source conductors.
>
You need a
> double pole, double throw switch, (DPDT).


I don't understand. So you have to presume the neutral is miswired
ungrounded (and potentially hot), even though that's supposed to be tied to
ground at the service entrance point? By that logic you can't assume ANY
conductor is grounded, and would need a THREE pole switch in case some nut
wired the ground prong hot.

Transfer switches for this
> task are available and not that expensive. Of course, proper use of cord
> an plug can accomplish the same goal.
>

I agree, that if you want complete peace of mind a DPDT transfer switch is
ideal, followed by hand-plugging cords; but I don't see how a properly wired
common neutral, switched hot configuration poses any particularly unusual
danger.

--
John Bange
'90 Vanagon - "Geldsauger"