Quote:
Originally Posted by glatt
Geez. I've got a screwdriver with a melted spot on it from a minor sparking accident in my own panel. I thought that was scary, but it was just a single pop and a couple little sparks. Nothing like this.
(Previous electrician had been sloppy removing insulation and there was a hot wire with a bit of exposed copper peeking out from a little gap in the insulation a good 6 inches from the end of the wire. Murphy's law says the screwdriver made contact with it while I was tightening a grounding wire in the panel.)
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i've done that. more than once. not in a panel but trying to remove a staple that was holding the romex to a beam when we were remodeling the bathroom about a year ago.
the second time was when i trusted that my roommate turned off the correct breaker on a circuit i was splicing into. i checked with my voltmeter but didn't have a good connection and passed off the 12 or so volts as back feed from the neutral wire (very common in households with unbalanced circuit breaker panels). nope. it was hot. me and my Klein wire tool found out the hard way.
that was 120 volts though. nothing like the (i presume 4160v that the guy was working with above)
i've also been zapped with 208v. now that stings a bit. ok, A LOT. happened last year around this time at the panel shop i used to work for. then one of my cow workers got hit with the 480v side of a step down transformer (480v down to 120v). his arm turned all kinds of shades of red!
complacency is the bane of the existence of work related injuries. kinda why i started this thread. learn from others mistakes, and maybe even your own. talking about or reliving a mistake you made or a friend/cow worker at work or on an odd job around the house might make you think twice about safety and remember to be vigilant in whatever dangerous task is at hand.
let's reflect here. in the cases i mentioned above, i was hit with 120v and 208v. didn't kill me. know why? amperage. it's all about the amperage (with duration of electrocution thrown in as well)
from OSHA's
website:
Three primary factors affect the severity of the shock a person receives when he or she is a part of an electrical circuit:
Amount of current flowing through the body (measured in amperes).
Path of the current through the body.
Length of time the body is in the circuit.
Other factors that may affect the severity of the shock are:
The voltage of the current.
The presence of moisture in the environment.
The phase of the heart cycle when the shock occurs.
The general health of the person prior to the shock.
Effects can range from a barely perceptible tingle to severe burns and immediate cardiac arrest. Although it is not known the exact injuries that result from any given amperage, the following demonstrates this general relationship for a 60-cycle, hand-to-foot shock of one second's duration:
Current level (Milliamperes) Probable Effect on Human Body:
1 mA Perception level. Slight tingling sensation. Still dangerous under certain conditions.
5mA Slight shock felt; not painful but disturbing. Average individual can let go. However, strong involuntary reactions to shocks in this range may lead to injuries.
6mA - 16mA Painful shock, begin to lose muscular control. Commonly referred to as the freezing current or "let-go" range.
17mA - 99mA Extreme pain, respiratory arrest, severe muscular contractions. Individual cannot let go. Death is possible.
100mA - 2000mA Ventricular fibrillation (uneven, uncoordinated pumping of the heart.) Muscular contraction and nerve damage begins to occur. Death is likely.
> 2,000mA Cardiac arrest, internal organ damage, and severe burns. Death is probable.