While the dangers of electric shock are widely
understood—or at a minimum feared—the hazards presented by arcing faults are
not fully grasped by those outside the electrical industry. Arcing faults become exponentially bigger and
more frightening as you approach the power provider supply lines and the
sources of electricity.
Most of us like to think of the danger presented by
electricity in terms of volts. When
someone suggests, for instance, that they are working on a 480-volt system, the
inclination is to whistle as an expression of respect or wonderment. But it is the amperage, the actual measure of
current flow that creates the blast at the point of a circuit fault.
And that is the point…we are talking about an actual
explosion here.
Fact is, you can be killed by an arc flash and never
receive an electric shock at all.
How can that be?
Consider the following facts:
—The
temperature at the point of an arcing electrical fault can reach 35,000°F,
something near four times the temperature of the surface of the sun.
—Any
copper involved at the points of arcing will vaporize and expand to 67,000 times
the volume of solid copper.
—Shrapnel
will be expelled in all directions at a rate of about 700 miles-per-hour.
—The
initial sound shockwave is nearly the equivalent of a 12-guage shotgun blast.
All of this in a fraction of a fraction of a
second. And sometimes, the arcing event
goes on and on. I have posted a video of
a substation melting-down to illustrate the awesome power released at an arcing
fault.
--Mitchell
Hegman
No comments:
Post a Comment