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Discussion in 'After Hours Lounge (Off Topic)' started by Thomas Newton, Oct 31, 2005.
BBC NEWS story A lesson in the dangers of electricity -- but kind of rough on the wife and kids.
I read where this has happened before (see link) but I'd love for someone with pro sound experience to explain how common this problem is....it seems like there would be some kind of limit to the amount of current that could pass thru the mic in such a situation. Straight Dope Article
I know it's horrible, but I couldn't help but laugh when I read this (I know, I'm a sick man but it stuck me funny). In this day and age who doesn't know that Electrical Equipment + Water = Death? Had they used a GFCI, the preacher would still be baptising. I'm sure the guy will get nominated for a Darwin.
See, that's the part that confuses me though. I've used many microphones before, and have never plugged one into an electrical outlet. There are some mics that take 3.3v of "phantom power" -- meaning there is actually power coming to the mic from the mixing board, but those are usually group mics, not personal mics. I guess the connection to the mixing board is enough, but I didn't think electricity passed through the microphone cord.
What else is the cord for then? Of course it is electricity that is passed through the cord. The mike translate sound into an electrical signal. For this freak accident to have occured, there needs to have been enough potential on the surface of the mike (or anything else the preacher was in contact with) to produce the relatively large amount of current necessary to kill even someone standing in a puddle of water. Bottom line: Faulty equipment. -- H
There's a Darwin Award, "Resistance Is Futile", for a man who accidentally killed himself with a 9 volt battery. Although in that case, the electricity wasn't passing through unbroken skin, but through the victim's insides.
Matt has a link to the Les Harvey electrocution. He was with Stone The Crows and died onstage in Swansea. But, it happens fairly often, just not usually leading to death. Keith Richards got zapped at a 1965 concert and a member of the Pixies also had a bad experience with a mike. How 800 people can watch their pastor stand in water and grab a mike without someone yelling, "Stop!" is beyond me. How about a wireless mike? That's sounds like a great idea when trying to put off the afterlife as long as possible.
What ever happened to 'Mr. Microphone' ? It could now be marketed to a whole new demographic as a 'life saving device' Keep an eye out at the local 'As Seen On TV' store
That's why you never see Benny Hinn standing in water.
There is a lot to be said for wireless mics/guitars. This situation is a problem with inadequate grounding. You don't need water to cause the problem. I have been shocked numerous times when two pieces of equipment I've come in contact with were not properly grounded. In the case of a mic, there is very little current running through the lines, but one side of that line is ground, and if it is floating at the mixer/amp, then the only place for current to flow is through the body to something that is grounded. Teeth are pretty uncomfortable as a conductor.
I am a part-time pro audio guy, and church sound guy, and this has been a hot topic for the last couple of days. Two possiblities. 1. The sound system was _totally_ ungrounded. This could happen because of the tendancy of some people to use cheater plugs and the like to fix buzzes and humms in systems. Combined with a defective piece of sound gear, the microphone was electricly hot, and the water was grounded through the building plumbing. The pastor completed the circuit. 2. A water heater or pump was defective, and the pool was ungrounded, (and un-GFCI'd) and he completed the circuit to a properly grounded sound system. I'm inclinded to think it was #1. Normal microphone type voltages (even with phantom power(48v)) are not enough to kill.
Talk about messing with a Higher Power
It doesn't take much to kill someone - a mere 50-150 milliamperes (.05 to .15 A) can be sufficient. Voltage matters, so does moisture. Other sources go down as far as 20 mA. Mind you, a regular breaker is in the range of 15-30A, so approximately 100x-200x larger than what is needed to kill. A good site for this info (OSHA, found via Google): How Electrical Current Affects the Human Body This is how even a handheld phone dropping into a bathtub can kill... ...and a very good reason to turn off power at the breaker/fuse when you're working on electrics.
Speaking of electric damage, I was badly burnt (by hot ash) when I was younger working at a factory. While in the hospital with 3rd degree burns for a month a guy came in the burn ward with a bad electric burn. This genius had, seriously now, decided to make some money by stealing the copper out of high power wires. He lived WAY out in the country mind you, but still. Anyway, his chosen method to down these lines was to climb the pole and cut them down with a CHAIN SAW. For this effort he enjoyed a painful run of electricity through his arms and up into his temple and then out the other side someplace. Pretty nasty, but not nearly as bad as it could have been. Then about 8 months later a former co-worker at that factory I was hurt at was doing some work at the transformer. There was a slight mist that day and he got hit with an accidental arc. It cost him his right arm and the muscles in his left arm that open your hand back up (he could squeeze but had to have a device with rubber bands pull his fingers open again). He just missed getting his heart tissue badly burnt and being killed, as it ran from one wrist across his body and then out the other wrist. The variety of paths through the human body make the results really nasty and dramatically different. But generally you can expect some serious internal tissue damage if the current is high enough to burn tissue (which doesn't take much). It might run muscle, or viens, or along the bone somewhat, whatever is the most attractive (low impedence) path.