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Author Topic: Girl Dies From Shock On City Street  (Read 12625 times)

John Roberts {JR}

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Re: Girl Dies From Shock On City Street
« Reply #20 on: February 21, 2014, 11:11:44 am »

Somebody (possibly JR) on a DIY electronics forum once said something like "a good coat of paint will stop 300 volts", in reference to wire insulation standards.

Worth noting that racked gear is often not very well grounded through the rack hardware since everything these days is nicely powder-coated.
That doesn't sound like something I would say.. while perhaps true. Paint or powder coat is an unreliable insulator for human safety, but as I recall it was common to mask off or grind off covering to provide a conductive path. Safety grounds connections sometimes specify lock washers and even things like double nuts to secure a reliable connection.

I was once able to specify an enameled wire as one of the two layers of double insulation inside a special switching power transformer but that was an obscure situation, and an expensive work around to avoid several more months of high temperature testing delaying a new product from export markets.   

When in doubt make sure a ground bond is robust, and insulation likewise adequate.

JR

PS: perhaps you were thinking of my expert witness experience regarding electricity jumping across an air gap. While in human safety mains voltage spacing is typically 1/4", which is arguably a generous safety margin, but not crazy.

 
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Jonathan Johnson

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Re: Girl Dies From Shock On City Street
« Reply #21 on: February 21, 2014, 12:11:51 pm »

"if they had installed the ground wire, every time there was a power surge, it would trip the breaker and all he would get done would be resetting the breaker."

Defeating a safety mechanism (killing the messenger) is not a valid solution to a problem. If there is a problem with a breaker or a GFI tripping, then you need to identify the cause of the tripping and rectify it. If it's because Joe Lead's precious guitar amp has a current leak to ground, that's potentially an unsafe situation* and the amp should not be allowed to be plugged in until the problem is rectified. If Joe Lead is the hottest act in the Top 40, tough beans. When the public is involved, safety should always win over popularity, convenience, money, or arrogance.

That's not to say we should be zero-tolerance zealots. There are many ways things can be built that don't strictly meet the letter of the code, don't have an engineer's stamp, or aren't certified, but are completely safe nonetheless. Common sense must always be present.


*On the other hand, if through thorough testing you can determine that the current leak does not pose any kind of a shock or fire hazard, or you can implement a safe way to connect it, then maybe you'll allow it to be plugged in.
« Last Edit: February 21, 2014, 12:17:20 pm by Jonathan Johnson »
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frank kayser

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Re: Girl Dies From Shock On City Street
« Reply #22 on: February 21, 2014, 07:07:44 pm »


That's not to say we should be zero-tolerance zealots. There are many ways things can be built that don't strictly meet the letter of the code, don't have an engineer's stamp, or aren't certified, but are completely safe nonetheless. Common sense must always be present.

In my mind, you are probably right.  Problem with replacing tried-and-true known safe practices with our common sense is that different folks have different levels of basic common sense. Can we always trust our substitution of judgement?  We think so, but then isn't that judgement substitution that caused that little girl's death?  Wasn't a problem for x years...

Yeah, I've read on this forum that a show was shut down because some power cables were SJOOW vs SOOW.  If all cables were of similar age and maintained well, my common sense would tell me it would be OK to substitute.  How about new work metal quad boxes without a kellums as a stringer?  We've all used them at one point or another...

No, I don't think any of us want to be zero tolerance zealots, but how does one draw the line?
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Jim Rutherford

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Re: Girl Dies From Shock On City Street
« Reply #23 on: February 21, 2014, 10:04:01 pm »

Standards and code draws the line. 
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Mike Sokol

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Re: Girl Dies From Shock On City Street
« Reply #24 on: February 22, 2014, 06:31:10 am »

Standards and code draws the line.

One of the problems in the USA is that the NFPA 70 (National Electrical Code) isn't universally adopted in all states. It's really more of a stern suggestion than actual law of the land. It's up to each state to decide when (and if) to adopt each new code edition, and if they'll accept all parts of it. For instance, there's a bit of a war going on about requiring AFCI breakers (Arc Flash Circuit Interrupters) in homes. In a number of states, the local code legislators have ignored this code requirement for new home builds using the logic that the $300 additional cost for a $150,000 home build will depress the new home buying market. And many say there are too many random trips and that they really don't prevent fires (as advertized). Now I'm not going to jump into that battle simply because I've not done any personal research on the topic. But that's just ONE of the variations in applied code we all have to deal with. You really don't know how a building is wired in the US until you confirm it yourself.
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Jonathan Johnson

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Re: Girl Dies From Shock On City Street
« Reply #25 on: February 22, 2014, 01:02:31 pm »

Standards and code draws the line.

But standards and codes vary -- and sometimes conflict -- from jurisdiction to jurisdiction. Remember also that this is an international forum, and while codes between jurisdiction can vary slightly within the United States, between other countries the variations can be significant. If codes exist at all.

Common sense with an understanding of the fundamentals of electrical safety should rule where codes do not.
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Tim McCulloch

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Re: Girl Dies From Shock On City Street
« Reply #26 on: February 22, 2014, 01:24:44 pm »

But standards and codes vary -- and sometimes conflict -- from jurisdiction to jurisdiction. Remember also that this is an international forum, and while codes between jurisdiction can vary slightly within the United States, between other countries the variations can be significant. If codes exist at all.

Common sense with an understanding of the fundamentals of electrical safety should rule where codes do not.

Look at the photos posted by forum participants from India... if there is any form of regulation there it has no enforcement powers.  Not to veer too far off topic, but the same is true of India's chemical and pharmaceutical industries.
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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

Mark Cadwallader

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Re: Girl Dies From Shock On City Street
« Reply #27 on: February 22, 2014, 02:00:49 pm »

But standards and codes vary -- and sometimes conflict -- from jurisdiction to jurisdiction. Remember also that this is an international forum, and while codes between jurisdiction can vary slightly within the United States, between other countries the variations can be significant. If codes exist at all.

Common sense with an understanding of the fundamentals of electrical safety should rule where codes do not.

The level of risk vs. safety that a given society deems acceptable is a matter of culture, accepted practices, and (often) economic forces.  Even within the U.S. there is not agreement about what safety precautions are appropriate and "cost effective."  The EU has different standards than the US and Canada; that other countries and regions vary is hardly surprising.  I have to continually remind myself that my view of "the right thing to do" is not universally shared (or generally accepted from a global perspective).  Mark C.
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Stephen Swaffer

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Re: Girl Dies From Shock On City Street
« Reply #28 on: February 23, 2014, 03:54:37 pm »

I try not to to be a "letter of the law" zealot either-but even before the NEC was mandatory in much of the rural area I work in, I still felt it a good practice to follow it. I don't have the time or money to test various methods, or the combined experience that goes behind the issuing of the NEC (admittedly, politics and money come in to play at times-that is unavoidable).  If nothing else, I felt like having the code on my side if something happened would help with liability issues.   Ask yourself, "Do I have more experience than is present on the code panel responsible for this section?"

As for SJOOW vs SOOW substitution-keep in mind SJOOW is 300 volt rated, SOOW is 600 volt rated-if you are working with 480 VAC systems, substitution would be a big deal.

Mike, I hear the AFCI argument quite often-and don't like the extra cost either.  However, as one inspector pointed out to e, the extra cost of granite counter tops (typically much more than a $300 adder for a home) hasn't discouraged their popularity.  People have the right to chose where to spend their money on their home, but when we are dealing with the public we have a responsibility to be worthy of their trust that they will be reasonably safe.
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Tim McCulloch

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Re: Girl Dies From Shock On City Street
« Reply #29 on: February 23, 2014, 04:50:32 pm »

As for SJOOW vs SOOW substitution-keep in mind SJOOW is 300 volt rated, SOOW is 600 volt rated-if you are working with 480 VAC systems, substitution would be a big deal.

Actually it's NEC 520 & 525 that require "extra hard service" cabling when our events are outdoors or in a theater or arena.  No "J" in the type designation for us, even if the service voltage is 120/208v.
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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
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