[LAU] Ground lifts, TRS, etc. to PA? USB/other signal crossover to audio?

[Reuben Martin]

On Friday, May 09, 2014 07:14:53 PM Will Godfrey wrote:
> On Fri, 09 May 2014 13:01:57 -0500
> 
> Reuben Martin <reuben.m at gmail.com> wrote:
> > On Friday, May 09, 2014 06:05:47 AM Ralf Mardorf wrote:
> > > On Thu, 2014-05-08 at 18:02 -0500, Reuben Martin wrote:
> > > > On Friday, May 09, 2014 12:44:00 AM Jörn Nettingsmeier wrote:
> > > > > On 05/08/2014 09:30 PM, Jonathan E Brickman wrote:
> > > > > >  AC power ground lifts sometimes have helped, sometimes
> > > > > 
> > > > > There is no such thing as an AC power ground lift. The correct term,
> > > > > and
> > > > > please don't take it personally, is _criminal_ _incompetence_.
> > > > 
> > > > It sometimes makes sense to lift the AC ground if you are pulling
> > > > power
> > > > from more than one source. (To prevent ground loops) As long
> > > > everything
> > > > is grounded to the remaining source correctly.
> > > 
> > > Potential difference by getting the power from different main jacks or
> > > experiencing ground loops, because you don't care about a correct
> > > grounding are no excuse to give a life-endangering "hint".
> > 
> > I'm not suggesting to cut the ground pin off. When you use an AC ground
> > lift they come with a metal ring to re-direct the ground connection so
> > that equipment using different power sources can share a common ground.
> Link to highly dangerous item not repeated!
> 
> How on earth is this legal? Do you *really* think most people will be savvy
> enough to know that you're supposed to connect the tab to a proper earth?
> Would they even know what a proper earth was?
> 
> There is absolutely no way of ensuring the earth is ever connected at all! A
> properly designed 3pin connector ensures the earth is always connected
> first, and disconnected last. It's the *only* safe way to work.

Perhaps I assume too much thinking the proper handling of power and wiring is 
common knowledge. I deal with power issues on such a regular bases in my job, 
that I sometimes forget that all too often people are messing with power who 
have a very poor understanding of what they are doing.

I work in large event audio-video-lighting production, so it's very common for 
me to be encounter power hazards that would probably give most people on this 
list the creeps.

-Reuben