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Author Topic: brain storm an optimal human safety system for back line  (Read 102451 times)

Lyle Williams

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Re: brain storm an optimal human safety system for back line
« Reply #100 on: January 01, 2015, 06:14:43 pm »

What I want is a VOM about the size/shape of a beer can that plugs into the end of a long electrical extension cord.  Ie, a tester that is referenced to another outlet.

Yes, I can do this with regular multimeter probes but it is fiddly.
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Mike Sokol

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Re: brain storm an optimal human safety system for back line
« Reply #101 on: January 01, 2015, 07:35:57 pm »

What I want is a VOM about the size/shape of a beer can that plugs into the end of a long electrical extension cord.  Ie, a tester that is referenced to another outlet.

Yes, I can do this with regular multimeter probes but it is fiddly.

I've actually designed such a gadget on paper, but didn't think it had enough general interest to be a commercially viable product. I guess JR is rubbing off on me... ;D
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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 #102 on: January 01, 2015, 08:17:59 pm »

But I think it's got all the "right stuff".

Including "JR Approval"-a step up from "UL Listing" methinks :D

If everything that had wiring to the stage-including FOH mixer-had the GFCI with stinger cap it would take multiple failures to cause an electrocution. 
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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 #103 on: January 01, 2015, 09:08:32 pm »

Don't let me talk you out of any million dollar ideas... (psst this probably isn't one.)

JR

PS: I think I know the company to manufacture the MUSO outlet strip... I'd use "Stinger" in the name... But first lets make sure there are no snakes in the wood pile.

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Don't tune your drums half-ass. Listen to what a properly "cleared" drum sounds like.   http://circularscience.com/

Peter Morris

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Re: brain storm an optimal human safety system for back line
« Reply #104 on: January 01, 2015, 11:31:05 pm »

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

Hi JR,
Given the brain storming request - FWIW this is what happens in industrial / mining applications for large equipment using trailing cables.

There is a control panel which contains the connection socket.

The control panel contains;

   3 phase RCD (GFIC) protection.
   AC detection for the earth (the screen in the cable)
   Detection that the earth connection (and cable) has been made (there is a pilot wire in the training cable that provides the return circuit etc.)

If a fault is detected the control panel will not energise the equipment, or as you described latched off.

There is a requirement for routine inspection and testing, and things like earth resistance / leakage current are data-dogged.

There are other tricks used for very large installations where the supply star point is connected to ground through dynamic impedance. Under fault conditions the impedance is matched (complex opposite) to that of the fault. The potential at the fault is therefore greatly reduced. (a modern version of the Peterson coil)

http://www.connetics.co.nz/assets/Uploads/Technical-information.pdf





« Last Edit: January 01, 2015, 11:35:38 pm by Peter Morris »
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John Roberts {JR}

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Re: brain storm an optimal human safety system for back line
« Reply #105 on: January 02, 2015, 10:07:09 am »

Thanks Peter... sounds like a good system to reduce risks in a hazardous environment. I have seen the shielded line cords with power cut-off, should leakage occur to the line cord shield, for sale by the company that makes GFCI outlet strips, but I've never seen them in use (AFAIK).

I fell like we will come up with an actionable plan by the end of 2015...To keep our guitar playing singers alive.

JR
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Don't tune your drums half-ass. Listen to what a properly "cleared" drum sounds like.   http://circularscience.com/

Stephen Swaffer

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Re: brain storm an optimal human safety system for back line
« Reply #106 on: January 02, 2015, 01:47:11 pm »


Don't let me talk you out of any million dollar ideas... (psst this probably isn't one)


I am seeing more and more similarities between farmers and musicians.  Have yet to meet a farmer that can afford to have me wire something correctly-but almost never see a rusty combine working a field-they seem to always be able to afford a new one.  Given the cost of some of the vintage guitars/amps, would a $100-$150 safety device really break the bank?  Really?

Of course, there is always a cost vs benefit consideration-even on safety.
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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 #107 on: January 02, 2015, 03:13:17 pm »

I am seeing more and more similarities between farmers and musicians.  Have yet to meet a farmer that can afford to have me wire something correctly-but almost never see a rusty combine working a field-they seem to always be able to afford a new one.  Given the cost of some of the vintage guitars/amps, would a $100-$150 safety device really break the bank?  Really?

Of course, there is always a cost vs benefit consideration-even on safety.
Perhaps that is why seat belts and air bags and ABS brakes are mandatory, otherwise they would only be found on high end Mercedes.

I don't think we lose enough musicians to make this stuff mandatory, but GFCI and a smart ground lift might be a merchantable feature if engineered inside a premium (Mercedes) guitar amp.

JR

PS: I understand perceived cost benefit, I try to sell drum tuners to musicians with multi-thousand dollar drum kits, not willing to pay a couple hundred more to make them sound better.  :P  But the customer is always right.  ::)
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Don't tune your drums half-ass. Listen to what a properly "cleared" drum sounds like.   http://circularscience.com/

Stephen Swaffer

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Re: brain storm an optimal human safety system for back line
« Reply #108 on: January 02, 2015, 03:40:21 pm »


I don't think we lose enough musicians to make this stuff mandatory....


Cost is measured in $, benefits in musicians-how many does it take to equal out? :o   Don't ask me during a soundcheck!!
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Steve Swaffer

Jonathan Johnson

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Re: brain storm an optimal human safety system for back line
« Reply #109 on: January 03, 2015, 05:42:20 pm »

I am seeing more and more similarities between farmers and musicians.  Have yet to meet a farmer that can afford to have me wire something correctly-but almost never see a rusty combine working a field-they seem to always be able to afford a new one.  Given the cost of some of the vintage guitars/amps, would a $100-$150 safety device really break the bank?  Really?

Very few of those shiny new combines were paid for with cash. Quite often only one payment is made per year: when the check from the co-op elevator comes in.

As an electrician, are you OK with waiting until next fall to be paid?

Granted, musicians aren't exactly in the same boat, but many are probably on the E-Z Payment Plan for their gear.

Besides, farmers and musicians don't see safety as a profit center.
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Stop confusing the issue with facts and logic!

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Re: brain storm an optimal human safety system for back line
« Reply #109 on: January 03, 2015, 05:42:20 pm »


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