Monthly Archives: March 2017
Lock It Out
When electricity was in its infancy, a battle between inventors forever changed the way we use our most popular power source. Here’s the story.
In 1882, all the electricity in the country was supplied by direct current, thanks to the inventiveness and industriousness of Thomas Edison. Then in 1884 Edison hired the brilliant Croatian scientist, inventor and theoretician Nikola Tesla to sort out the problems with the DC system. Tesla saved Edison $100,000, -over $1 million by today’s standards. However, the scientists had a falling out.
Tesla left Edison’s company and went on to invent a better system, alternating current and eventually signed a contract with George Westinghouse. AC offered several advantages. For example, it could be stepped up and transmitted over long distances on thin wires, while DC required a large power plant every square mile and very thick cables.
Because Edison was heavily invested in direct current, he attempted to discredit Tesla. Edison staged “experiments” involving animal electrocution to try to show that Tesla’s system was dangerous. Tesla retaliated with his own demonstrations to show that alternating current was controllable. He used his invention, the Tesla Coil, to generate huge lightning bolts to the amazement of his supporters.
In the end, AC won out, and Tesla was vindicated. He also realized his dream of bringing affordable, abundant electric power to homes and businesss through- out the country. Although they did not agree on the merits of AC versus DC, both Tesla and Edison knew that electricity is a powerful force to be used only with great caution and respect. The same holds true today.
*When you follow lock-out and tag out each and every time machinery is shut down for repair or maintenance.
*Before starting work on an engine, motor, lathe, saw or any power driven equipment, take all of the steps required to neutralize the power sources.
*Place locks and warning tags on all switch boxes, valves and controls.
*Clearly print complete information on the tag so that others know when, where and why the equipment was locked out.
Short-Circuit An Accident…Always Lock Out and Tag Out
* Copyright 2002 Harkins Safety (B-155)
An Idea Strikes
Have you ever watched lightning during a storm and wondered about its power? If so, you’ve embarked on the same scientific exploration that propelled Ben Franklin more than 200 years ago. Franklin was so enthralled with electricity that its study was his lifelong hobby.
In fact, it was Franklin who invented the lightning rod. In one of his experiments, he observed that a sharp iron needle would conduct electricity away from a charged metal sphere. He further theorized that lightning might be drawn away from buildings by elevating an iron rod grounded to the earth and the lightning rod was born.
But Ben didn’t stop there. He later had a theory that lightning was actually electricity. In June of 1752, he grew impatient waiting for the steeple on top of Christ’s Church to be completed for his experiment. The steeple would act as a lightning rod. So he thought that a kite would be able to get as close to the storm clouds. He tied a metal key to the kite string, and tied the string to an insulating silk ribbon for his hand. When Franklin saw the lightning deliver its charge to the key, he knew immediately that it was a form of electricity. And he knew its power.
Upon receiving an electrical shock during one experiment, he described it as a “ universal blow throughout my whole body from head to foot…and a violent quick shaking of my body…”
Ben took huge risks in his experiments and fortunately never received a fatal shock. But we know that electricity is a powerful force that can injure and kill. We have to treat it with the utmost respect. Always check electrical equipment and power cords for damage. Make sure electrical equipment and machinery are properly grounded. Always lock out and tag out, it you’re the worker authorized to do so. Check to ensure that equipment is powered down before you begin maintenance and repairs.
Franklin was obsessed with the idea of electricity. In 1749, he described the concept of a battery in a letter to a friend, but doubted if it would ever be of use. Like Franklin, we should think about electricity too. Not by conducting experiments but by staying aware of how to safely work with electricity. Electricity is so common that we can become too comfortable around it. That’s a mistake. Stay alert to the very real dangers of electricity. It’s one of our greatest allies but also one of our greatest threats.
Beware if Electricity’s There!
*Copyright 2008 Harkins Safety B-233