Article
Long, long ago … in a galaxy far, far away …<br><br>Well, it was really 
about 40 years ago and around 700 miles from where I'm sitting right 
now. Anyway, I was employed by a water softener company in northern 
Indiana. I roamed the highways and byways of the Indiana and 
northeastern Illinois countryside, installing and repairing softeners in
 farmhouses, spec homes, and rural domiciles.

It's Not Always the Voltage That Kills You

Steve Maurer, IME
Long, long ago … in a galaxy far, far away …

Well, it was really about 40 years ago and around 700 miles from where I'm sitting right now. Anyway, I was employed by a water softener company in northern Indiana. I roamed the highways and byways of the Indiana and northeastern Illinois countryside, installing and repairing softeners in farmhouses, spec homes, and rural domiciles.

And delivering salt.

Not my favorite part of the job … it came with quite a few heart stopping thrills, for sure.

I spent a lot of time driving around with a huge load of salt bags loading down my delivery van. I'd often head out early in the morning, nose of the old Chevy pointed toward the sky.

Made for some interesting driving.

One day, I was cruising down Highway 30 when my van started to get that unwelcome lean to it. The passenger side back tire was losing pressure, so I quickly pulled over.

After jacking the van up and breaking the lug nuts loose sufficiently, I began to spin them off with my fingers.

Ouch!

It felt like a sliver of metal on the nut had pierced my finger tip. With the alleged barb still in my finger, I quickly removed the nut, then checked my hand.

No metal to be seen, strangely enough.

So I went on to the second lug nut … same thing.

In fact, each time I started to touch any of them, I felt a sharp, stinging pain in my fingertips. Looking up, I noticed I was parked directly under the powerlines, strung across the road from a series of towers.

It wasn't shards of metal that was gouging me … it was induced power shocks.

Grabbing a glove from the van, I snugged up the loose nuts and hobble down the road to change the flat tire … without getting the snot shocked out of me.

A newfound respect for linemen and linewomen
On my way I went … delivering the rest of my salt load after learning an important lesson: You don't have to touch the conductor directly to get hurt.

I went on down the "road" even farther to become an industrial electrician and equipment mechanic. But the lesson learned on the side of the road that day gave me a newfound respect, not just for those who work the high-power lines, but anyone working with electricity.

And a healthy respect for the little "zapper" itself.

From my early days, I had already learned that it wasn't just the amount of voltage that mattered, but the amperage as well. On a tour at the Peach Bottom Nuclear power plant during my "formative years," we touched like a bazillion volts with little or no effect other than frizzy hairdos. The amperage was extremely low.

I've studied several charts and graphs, and here's what I've learned from them.

You'll feel little or no shock from 1 to 10 mA (milliamps, not amps).

From 10 to 20 mA, it's painful, but no loss of muscle control (probably what I experienced when changing that flat tire).

At 20-75 mA, it get serious with a painful jolt and loss of muscle control. If you've grabbed the voltage source, you might not be able to let it go.

If the amperage is in the 75 to 100 mA range, ventricular fibrillation of the heart can occur. And from 100-200 mA, it will occur, often resulting in death.

Over 200 mA, internal organs can be damaged, not just the heart.

Now, think about this. House wiring can carry from 15,000 to 20,000 mA. Just think about what line workers can be exposed to on the poles and towers that provide the power to run our daily lives.
More efficient, reliable power is just one reason a lot of research and development goes into high voltage, high amperage power equipment, utility fuses and switches.

Protecting lives is another from shock and arc blasts is another, perhaps even more paramount concern.
Photo courtesy of Hubbell Power Systems, Inc.
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