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Author Topic: brain storm an optimal human safety system for back line  (Read 105276 times)

John Roberts {JR}

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Re: brain storm an optimal human safety system for back line
« Reply #90 on: January 01, 2015, 01:28:14 pm »



I have continued to think about the premium (smart outlet strip) solution and this is not cheap or trivial. Even with a microprocessor it isn't trivial to detect all the possible errors. My current thinking is to test for any bootleg ground (not simple) and warn if that is detected. If significant voltage or current is detected between the mains and equipment grounds the relay opens or never closes. I suspect this is too expensive, and market to small for this to ever happen, but fun to think about.

JR

Thinking some more about a premium outlet strip... I can source a 3 pole 10A relay so if any fault is detected before closing the relay doesn't close, and power never comes on. The unit will have an internal power supply so it can indicate the nature of the no-start fault. If in use it detects X mA of ground current it will open and stay latched off until reset. 

If we break line, neutral and ground, this should protect against all anticipated hazards. 

It may be interesting to hear what UL thinks about breaking the safety ground on purpose. The entire safety ground bonding rationale is based on shunting live faults to trip the associated breaker.

My cheapo mic ground to guitar ground diode shunt is consistent with the UL philosophy to take out the associated breaker.  My smart premium outlet strip with relay that releases ground (and power), may protect the meat sock from immediate hazard, and since it turns off the power, it will be hard (and ignorant) to just ignore.   

JR

PS: not cheap... onsey twosey.. relay is $25, suitable PS is probably around $20, GFCI outlet is probably the cheapest component. Micro only a couple dollars but PCB and glue $10. I may dummy one up just for fun, but ironically I don't have a grounded outlet in my house to test it with.  :o :o
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Tim McCulloch

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Re: brain storm an optimal human safety system for back line
« Reply #91 on: January 01, 2015, 01:36:15 pm »

Unfortunately people who can't (won't) take responsibility for their own  well being are too often the justification for government over reach.

I agree about the mental exercise-and hopefully the discussion will raise awareness and understanding among others.

As for the GFCIs for backline-I am curious how many of these venues are required to have periodic safety inspections?  It would be a minimal additional check to use a tester like my local/state inspectors use on every new recept in new construction.  I don't have as much problem with government "overreach" when they are mandating the landlord/venue meet certain standards to protect the tenant/customer.  It might help to pursue raising awareness of this hazard among the inspectors through the  Association of Electrical Inspectors.

I'm all for the government keeping people from being subject to abjectly stupid conduct, especially remembering that the Codes and regulations tend to be developed with the input of industry(ies) and then adopted by the various levels of government.  The NFPA has zero authority, likewise UL... but if your state, city or county adopts the codes or standards of either, you'll comply or....

Frankly I'm over pissy guitarists who hear shit that nobody else can hear (except other guitarists suffering from confirmation bias - sure the Emporer's new clothes are great!) and if their old gear kills them I'm *almost* fine with it if it happens because they're either cheap or paranoid about anything that changes their perceived "magic sound."  I love the instrument but some of its players are just batshit whacky, abusive or possibly mentally ill.
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John Roberts {JR}

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Re: brain storm an optimal human safety system for back line
« Reply #92 on: January 01, 2015, 01:50:24 pm »

I'm all for the government keeping people from being subject to abjectly stupid conduct, especially remembering that the Codes and regulations tend to be developed with the input of industry(ies) and then adopted by the various levels of government.  The NFPA has zero authority, likewise UL... but if your state, city or county adopts the codes or standards of either, you'll comply or....

Frankly I'm over pissy guitarists who hear shit that nobody else can hear (except other guitarists suffering from confirmation bias - sure the Emporer's new clothes are great!) and if their old gear kills them I'm *almost* fine with it if it happens because they're either cheap or paranoid about anything that changes their perceived "magic sound."  I love the instrument but some of its players are just batshit whacky, abusive or possibly mentally ill.

Yes but the customer is always right... If we can let the pissy guitar player plug his legacy POS amp into a smart outlet strip that protects him, without coming close to affecting his "tone" that should be all good... If it protects against rouge hot mic's too, all the better. 

Still not a commercial product IMO

JR
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Tim McCulloch

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Re: brain storm an optimal human safety system for back line
« Reply #93 on: January 01, 2015, 02:04:54 pm »

Yes but the customer is always right... If we can let the pissy guitar player plug his legacy POS amp into a smart outlet strip that protects him, without coming close to affecting his "tone" that should be all good... If it protects against rouge hot mic's too, all the better. 

Still not a commercial product IMO

JR

There is enough of this - killing or injuring players with dodgy gear, the occasional minister electrocuted in "hot" baptismals - that one would think the public would demand compliance with or the creation of, Codes and regulations.  But nope, when building codes/electrical codes are only enforced when legitimate contractors or qualified individuals pull permits and get inspected (and inspectors are a whole 'nuther matter), people will die, buildings will burn... and as soon as the bodies are buried the countdown of forgetfulness starts.

And the last part, John, is why I'm cynical.  The great umbrage that happens each time this occurs dissipates within a very short time; until the next wardrobe malfunction or celebrity rehab intake.  Basically nobody but us (and the few like-minded individuals around the world) give a damn if these folks have died for no reason.  It's a product that too few can see a reason for existence, while standing of the bodies of the dead.

Hmmm.  Maybe I need another coffee.  Naw, I'm hitting "post."
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"Practicing an art, no matter how well or badly, is a way to make your soul grow, for heaven's sake. Sing in the shower. Dance to the radio. Tell stories. Write a poem to a friend, even a lousy poem. Do it as well as you possible can. You will get an enormous reward. You will have created something."  - Kurt Vonnegut

Stephen Swaffer

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Re: brain storm an optimal human safety system for back line
« Reply #94 on: January 01, 2015, 02:23:39 pm »

I'm all for the government keeping people from being subject to abjectly stupid conduct, especially remembering that the Codes and regulations tend to be developed with the input of industry(ies) and then adopted by the various levels of government.  The NFPA has zero authority, likewise UL... but if your state, city or county adopts the codes or standards of either, you'll comply or....


In general, I tend to lean away from government mandates.  However, when the potentially harmed party is a third party I find the primary party often just asks "How cheap and will it work."  My personal definition of "work" by default includes the requirement that to be safe-but another contractor might well be willing to use a different definition and do it cheaper.  This is particularly aggravating to me when it comes to residential landlords-often they make decent money renting, but allow families to live in hazardous conditions they would not subject their own families to.

In this case, it only seems to make good economic sense.  It would be more cost effective for an inspector doing a safety inspection (assuming that already happens) to own and use an appropriate high quality tester to verify that receptacles are wired correctly than for every musician to have to own such a tester.  If the venue knows they will be tested, flagged and required to remedy shoddy work, soon enough they (hopefully) will decide it is better to do it once correctly than to pay for it twice.

In Iowa, the state will do a non mandatory inspection for $25-no government agency I deal with charges more than $50 for an inspection. If that kind of annual cost will make or break a venue,   IMO they are probably already broken.

What kind of value do we put on safety?
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John Roberts {JR}

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Re: brain storm an optimal human safety system for back line
« Reply #95 on: January 01, 2015, 02:59:03 pm »


And the last part, John, is why I'm cynical.  The great umbrage that happens each time this occurs dissipates within a very short time; until the next wardrobe malfunction or celebrity rehab intake.  Basically nobody but us (and the few like-minded individuals around the world) give a damn if these folks have died for no reason.  It's a product that too few can see a reason for existence, while standing of the bodies of the dead.

Hmmm.  Maybe I need another coffee.  Naw, I'm hitting "post."

I try to look at the world through economist eyes and we need to attempt to attach some perspective to the number of deaths from sundry causes. It is the nature of the human condition to respond to threats based on perception of being similarly affected personally combined with the megaphone effect of modern media that specializes in trying to scare viewers with news reports. a musician electrocuted on stage will briefly be in the spotlight because of celebrities getting disproportionate attention but the likelihood of viewers getting electrocuted by a mic and/or guitar are less likely than being hit by lightning. (33 killed by lightning in 2013). 

Bathtub or kitchen shocks are more likely and regulations have stepped up to meet that threat with GFCI outlets. 

I have always taken human safety seriously in association with product design and have long wrested with this "ground equals good" or "ground equals bad" conundrum.

I don't expect this two branch exposure scenario to rise to UL's taking action, since it involves an already illegal RPBG situation or a faulty ungrounded guitar amp. Leaky old guitar amps are already managed effectively with stock GFCI, and any musician who is unwilling to investing in personal GFCI to protect themselves deserves what they get.

A sound provider can use stock GFCI for back line to protect musicians from themselves. I probably would. I bought a cheap GFCI protected outlet extender (<$30) and may give it to a local musician when I'm finished playing with it. 

JR

PS: I wonder how many outlets are professionally tested with the 3 lamp testers that do not reveal RPBG? NCVT require some judgment to interpret due to false positives so I don't trust these as comprehensive remedies. Unless the inspectors approve the musicians back line gear too, I prefer the "here, plug into this outlet and you will be OK" approach. 
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Mike Sokol

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Re: brain storm an optimal human safety system for back line
« Reply #96 on: January 01, 2015, 03:22:31 pm »

PS: I wonder how many outlets are professionally tested with the 3 lamp testers that do not reveal RPBG? NCVT require some judgment to interpret due to false positives so I don't trust these as comprehensive remedies. Unless the inspectors approve the musicians back line gear too, I prefer the "here, plug into this outlet and you will be OK" approach.

I have all the parts together to build my stinger-cap/isolated-ground/back-line/GFCI receptacle this weekend. It could be the simplest/affordable/legal solution to this problem since it would protect the musician from everything I can think of including plugging their stage amp into an RPBG outlet, using an ungrounded stage amp with power transformer leakage or a line-to-chassis short, and even touching a hot-mic from an improperly grounded PA while holding a properly grounded guitar. Plus, it just might be possible to have it NEC and/or UL approved or at least an exception qualified. This is the same design I've discussed before, but I'm adding a neon light between the incoming and outgoing EGC (safety ground) which should alert you of an RPBG-to-EGC fault with a grounded DI box during hookup, as well as a hot-mic PA condition, but only while the musician gets between the mic and the guitar. And it would also light up the hot-mic neon bulb if you touch properly grounded guitar strings to a hot mic. Meat-puppet fault currents would be limited to a max of 6 mA both ways, so while it could sting a bit it should be safe. I'll post pictures and come up with a few test scenarios to demonstrate and measure how well it works.

The beauty of this design is that it could be built into an add-on stringer box for PowerCon connected outlets like Whirlwind and others build, as well as added to basic Edison extension cords for smaller stages.

We shall see, but I think the design has possibilities.   
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Mike Sokol
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Stephen Swaffer

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Re: brain storm an optimal human safety system for back line
« Reply #97 on: January 01, 2015, 03:34:33 pm »

I am not suggesting a $5 3 lamp tester-rather a tester more like what Mike has suggested (which is in fact what the inspectors I deal with use)-or even better if you were able to design a smart outlet strip that could reliably detect a RPBG condition that same technology could be used for a tester. In that case, it makes more sense for one tester to be used in a preventative implementation on multiple venues rather than having every musician invest in a tester to  test every venue he plays in every time-though I do prefer the latter from a personal responsibility stand point.

That said, reliance on government inspection has too many potential holes for me to stake my life on.
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Steve Swaffer

John Roberts {JR}

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Re: brain storm an optimal human safety system for back line
« Reply #98 on: January 01, 2015, 05:11:52 pm »

I have all the parts together to build my stinger-cap/isolated-ground/back-line/GFCI receptacle this weekend. It could be the simplest/affordable/legal solution to this problem since it would protect the musician from everything I can think of including plugging their stage amp into an RPBG outlet, using an ungrounded stage amp with power transformer leakage or a line-to-chassis short, and even touching a hot-mic from an improperly grounded PA while holding a properly grounded guitar. Plus, it just might be possible to have it NEC and/or UL approved or at least an exception qualified. This is the same design I've discussed before, but I'm adding a neon light between the incoming and outgoing EGC (safety ground) which should alert you of an RPBG-to-EGC fault with a grounded DI box during hookup, as well as a hot-mic PA condition, but only while the musician gets between the mic and the guitar. And it would also light up the hot-mic neon bulb if you touch properly grounded guitar strings to a hot mic. Meat-puppet fault currents would be limited to a max of 6 mA both ways, so while it could sting a bit it should be safe. I'll post pictures and come up with a few test scenarios to demonstrate and measure how well it works.

The beauty of this design is that it could be built into an add-on stringer box for PowerCon connected outlets like Whirlwind and others build, as well as added to basic Edison extension cords for smaller stages.

We shall see, but I think the design has possibilities.

The GFCI outlet strip with stinger cap ground is JR approvable. I like the neon lamp as a nice extra feature.  8)

(I have one GFCI strip on hand to modify while I have to buy a special screw driver to get it apart. It uses odd security screws.)

Non GFCI cords or outlet adapters with stinger grounds are not JR approvable. IMO the stinger cap is only really safe in combination with system GFCI/RCD). If an adapter could be used separately w/o the GFCI they probably will, so not completely safe.    >:(

JR

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Mike Sokol

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Re: brain storm an optimal human safety system for back line
« Reply #99 on: January 01, 2015, 06:01:36 pm »

The GFCI outlet strip with stinger cap ground is JR approvable. I like the neon lamp as a nice extra feature.  8)

(I have one GFCI strip on hand to modify while I have to buy a special screw driver to get it apart. It uses odd security screws.)

Non GFCI cords or outlet adapters with stinger grounds are not JR approvable. IMO the stinger cap is only really safe in combination with system GFCI/RCD). If an adapter could be used separately w/o the GFCI they probably will, so not completely safe.    >:(

JR

I'm also going with the idea of one Stinger-GFCI outlet per back-line stage amp. That way, any ground-fault leakages won't be additive from several back-line amplifiers. And if a guitar amp does trip a GFCI, it will only take out that single amp, not the entire back-line. Once I build and test the proof-of-concept design, then we can decide if it's affordable to build and if anyone will use it. But I think it's got all the "right stuff".
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Mike Sokol
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Re: brain storm an optimal human safety system for back line
« Reply #99 on: January 01, 2015, 06:01:36 pm »


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