Eletrcution by Mic

[blademaster]

Hey Guys I heard a few weeks ago about a Texan Pastor that got eletrcouted when either a mic fell into the water or he touched it. I'm wondering what you're guys opinion is on pssible causes as well as whether or not the shure Beta 58 handheld wireless mics could cause the same thing if they were to fall into the water. (i.e. how many amps does a 9v put out at a non-used full current drain)

[CHScrew]

I think that I heard about that too. I forget exactily how it happened but I know that it did. But I don't know how bad it was though. Did it do damage or was it just a little shock?

[AVGuyAndy]

First off, to answer the question "Did it do damge?"...the guy died, so yes, it did damage.

Second, this incident was not caused by phantom power, or power from a wireless mic. In fact, it was a wired mic which he touched.

Third, the guy was standing in a pool of water. The mic did not fall into the water, he simply touched it.

Before the incident, the heater in the pool was not working properly, and it was replaced, or repaired or something, and the guy who wired it, didn't do it well.

The moral of the stroy, make sure your gear is wired properly, and grounded. NEVER use a ground lift adapter if you have a noise problem. Using a ground lift adapter will kill you.

[blademaster]

thanks Andy. how about the other question. If i use a wireless handheld that takes a 9v will the battery getting shortcircuited have the amps to kill a man

[AVGuyAndy]

Nope, not even close.

[blademaster]

off hand do u know how many amps it does produce being shortcircuited

[jumpjet]

Typically with no resistance, the amps will just increase to the maximum output of the battery. Ohms law: E= IR, if R is 0, no matter what voltage is, I can go from 0-infinity. That being said, There is a power limitation based on the power equation. P=IE. Without the amount of power neccesary, you will run out of amps. It only takes a tiny bit of current to send the heart into fibrulations(sp) so be careful!

[Radman]

That's right, it only takes around 50 milliamps to be fatal, and the fatility is not directly related to voltage.

Also, never use a multimeter to try and measure the amperage of a battery, something will most likely explode. The amperage rating of a component is what it draws, and the amperage rating of a circuit is the maximum amperage it is designed to withstand. A multimeter measures the amperage being drawn by a component.

[Mayhem]

Originally Posted by blademaster

thanks Andy. how about the other question. If i use a wireless handheld that takes a 9v will the battery getting shortcircuited have the amps to kill a man

Think about it - ever tested a 9V battery by touching the terminals to your tongue? Well that is what shorting it out feels like.

One of the most important factors in electrocution is resistance. When your skin is dry the resistance is high, when it is wet, the resistance is lower. Those of you that have worked on, or grew up on a farm will know the difference in getting bitten by the electric fence in summer as opposed to winter!

The other important factor is the ampage (as radman pointed out).

The 12V ignition coils on some cars actually carry a warning sticker as the amperage that they generate is enough to cause a serious (potentially fatal) shock.

I got a shock a few months ago from a 240V 16A breaker that had a break in the insulator and suffered nothing more than muscle contractions for the duration of the shock (it actually took a few seconds for me to work out what was happening) and then some general arm soreness for a few hours after. Fortunately, I was sitting on a wooden work bench at the time and my hands were dry.

I would have to check on the 50mA rating, as I suspect that would be current going directly into the heart (via pacing wires or intra-operatively). I do know that the number of joules used in an open defibrillator is approximately 10% of that delivered externally (with conductive gel pads).

[Radman]

30mA across the human heart kills.

Kindof related.