10 Mistakes In Electrical

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10 mistakes people make working on electrical systems
By Jim White, Shermco Industries
1. Thinking that it's "only 120 volts" or 208 volts or 480 volts or... "It's only low voltage." Okay, I'll admit that you can have an open casket with a low-voltage hit, but you'll still be dead. The onlydifference between low and high voltage is how fast it can kill you. High voltage kills instantly; low voltage may take a little longer. Dr. A.G. Soto, consulting physician to Ontario Power Generation presented a paper at the 2007 IEEE Electrical Safety Workshop discussing low-voltage shock exposures. In that paper, he stated that a 120-volt shock can kill up to 48 hours later. He also statedthat many emergency room physicians are unfamiliar with electric shock and that an EKG may not show a problem. The injury to the heart muscle tends to spread over time and cannot always be identified using EKGs. 2. Working on energized systems or equipment when it can be de-energized. This is a "man-thing". When I was working in a power plant (back in the 70s), we never de-energized anything, whetherit could be or not. My boss had a great contempt for anyone sissy enough to actually ask to de-energize before working. He would tell anyone foolish enough to suggest turning it off, "You're an electrician, work it hot! That's what you're trained to do!" His other favorite saying was, "If you want to be here tomorrow, you'll get this done today". Can you feel the love? De-energizing is the onlyway to eliminate hazards. Arc flash personal protective equipment (PPE) just increases your chances of survival; it doesn't guarantee it. Just be aware that until equipment and systems are placed in an electrically-safe work condition, proper PPE and procedures must be used to protect the worker. See Article 120 in NFPA 70E 2009. 3. Not wearing PPE. This could go into number 2 above, but peoplereally don't like

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06/07/2012 08:59 p.m.

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wearing rubber insulating gloves or arc flash PPE and equipment. It's hot, uncomfortable, restricts movement, and slows the entire work process down -- not only by wearing it, but by selecting the correct PPE and putting it on and taking it off. Itwill also save your life. One of the most likely times people neglect to wear their PPE is during troubleshooting. The rationale seems to be, "I'm not really working on it; I'm just testing it." Yet, CDC/NIOSH studies have found that 24% of electrical accidents are caused by troubleshooting, voltage testing and like activities. We have a tendency to ignore hazards associated with tasks we consider"safe". Back at my old job, when I was surveying a 480-volt 250 amp molded-case circuit breaker, the worker I was with put his bifocals up on his forehead so he could read the label on the breaker. He dropped his glasses back to his nose and immediately the breaker blew up! Luckily, he only had some red dots on his face and some singed hair, as he was backing his head out when it let go. Metaldroplets were imbedded into the lenses of his glasses, but because of them, he wasn't seriously injured. We investigated why that breaker might have failed and never found a good reason; it was just time for it to fail. Carbon buildup from earlier fault interruption, eroded contact materail that gets sprayed up into the arc chutes, weakened dialectric due to the extreme heating of arc interruption;all of these weaken circuit breakers and could have caused what seemed like a perfectly good breaker to fail suddenly. You never know. 4. Going to sleep during safety training Nothing like a good nap to get you ready for a hard day's work! Every Monday morning Shermco does a one-hour safety meeting for all technicians. We call it the "Monday Moaner", because the technicians really want to be at...