ground loop isolator and band aid fixes...

[Whoops]

So searching found a thread with your gfci box.

I searched for the thread but couldnt find it,
can you please show the link?

thank you so much

 

[JohnRoberts]

I searched for the thread but couldnt find it,
can you please show the link?

thank you so much

There may be more than one thread since I did a lot of work trying to save musicians from themselves but likely none that UL would embrace, without liberal application of Benjamins (not a bribe per se, but an expensive process).

The project that applies best to this thread was my simple ground lift mod to a commercial GFCI power drop.

In principle the GFCI power drop will still protect meat puppets against stray currents even without a safety ground connection.  For my prototype I added a ground lift switch to alternately test with the 0.16uF cap in series with safety ground shorted or not.

I sized the 0.16uF cap large enough to trip the GFCI (6 mA) in case of fault, but still low enough current to not likely harm humans.

===

Even if you don't make my ground lift capacitor modification, commercial GFCI power drops are not that expensive and can protect musicians who plug their "killer" (safety ground disabled) guitar amps into them. 

  https://www.amazon.com/26020008-6-Shockshield-Protected-Tri-Cord-3-Outlets/dp/B000HHQIK2/ref=asc_df_B000HHQIK2/?tag=hyprod-20&linkCode=df0&hvadid=194019628201&hvpos=1o1&hvnetw=g&hvrand=14110861499019042795&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9013964&hvtargid=pla-313052272940&psc=1
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In another more involved project I designed a protective power drop that not only included a GFCI outlet to disconnect power if the current fault was coming from it's outlet, but would also sense for external current flowing in the safety ground from anywhere else and disconnect that ground path with a relay after detecting a significant fault current. 

UL would never bless this approach as they promote rigorous safety ground bonding, but in fact a vector for performance related shock hazards is when the front of house safety ground is at a different voltage potential from backline safety ground, shocking performers when a supposedly grounded microphone body is hot relative to guitar strings (or vice versa). My device would protect against even that obscure scenario, but I abandoned it years ago as too hard/expensive to ever get approved by UL, to sell to customers who don't like spending extra money on safety.

JR 

 

[boji]

front of house safety ground is at a different voltage potential from backline safety ground

I discovered ground differentials the hard way when running internet to a self-service package system. I was drilling thru a concrete wall and had my hand on the top of a metal amazon cabinet, and when my other forearm brushed against the room's drop ceiling metal support...Zap! 

 

[JohnRoberts]

I discovered ground differentials the hard way when running internet to a self-service package system. I was drilling thru a concrete wall and had my hand on the top of a metal amazon cabinet, and when my other forearm brushed against the room's drop ceiling metal support...Zap!

Those are the good ones that you can complain about, not have somebody else write about how you died...

JR