I knew I should have taken that Science elective in University.

Jeff
Arts Student

On 11-Apr-09, at 12:41 AM, David Beierl wrote:

> At 08:28 PM 4/10/2009, pickle vanagon wrote:
>> I'm concerned about whether the buzzing is something to be worried
>> about
>> otherwise.  It's faint enough that you don't really hear it unless
>> you get
>> down on all fours right next to the outlet.  But is the vibration
>> creating
>> an unsafe situation?
>
> The maker of the GFCI should know better than we do whether that
> stepped square wave is ok for his device...
>
> ...but we can say that the vibration is not going to hurt anything.
>
> Whether the rest of the installation is safe is a different
> question.  Tentatively, it sounds ok to me, *with the transfer
> switch.*  Keep in mind that normally neutral and ground are tied
> together somewhere nearby, which would probably destroy the inverter
> if it connected to such a situation; but with the outlet isolated I
> think you're all right unless you plug in a device with a hot-ground
> or neutral-ground short in it, which will take down the inverter.
>
> The inverter doesn't really have a neutral -- both terminals are hot
> w/ respect to chassis ground, just like a (US) household 220 vac
> circuit.  Some inverters use a dummy ground terminal on their
> socket(s).
>
> Another point -- I'm quite sure I've read that modern GFCIs do not
> measure current flowing in the ground leg, but instead algebraically
> sum the hot and neutral legs and trip when the difference exceeds 5
> ma.  Thus they don't care where the missing current is going, and can
> operate fine with a two-wire hookup.
>
>
> --
> David Beierl - Providence RI USA -- http://pws.prserv.net/synergy/Vanagon/
> '89 Po' White Star "Scamp"