Page 28 - Occupational Health & Safety, December 2017

ELECTRICAL SAFETY
indicate that work inappropriately performed on energized equip- ment is associated with a substantial share of electrical injuries.
An important part of the LOTO procedure is proving that there is no power in the circuit supplying the machine, which can be time consuming. This process can include donning cumbersome personal protective equipment and opening the switch to manually probe wires using a volt meter to confirm zero power. Replacing a simple motor may take an hour or longer; however, taking short- cuts can cause serious ramifications.
Leading vendors have responded by developing innovative components that help protect workers while maximizing pro- duction uptime. OSHA estimates show that compliance with the LOTO standard prevents more than 100 fatalities and tens of thou- sands of injuries annually.
The latest development is a LOTO solution that protects against exposure to electrical energy and can be connected or disconnect- ed quickly and safely. Unlike standard connectors, devices rated to UL 2682 can operate as switches and be used to safely disconnect equipment while energized. Spring-loaded silver-nickel contacts provide switching capabilities similar to a switch or contactor and also offer a low-resistance connection.
A two-step connector operation places the plug in a rest posi- tion after disconnection, requiring a rotating motion to remove the plug while simultaneously closing the receptacle shutter. The posi- tive and quick LOTO system can safely disconnect equipment— using the separation of the plug from the receptacle as proof-posi- tive power is removed.
Maintaining a Balanced Current
Companies also can keep workers safe through the disciplined use of ground fault circuit interrupters (GFCIs) in wet and hazardous settings. Since being required for use in the late 1970s on 120V, single-phase, 15 and 20A temporary receptacle outlets used on construction sites, GFCIs in the construction industry have saved between 650 and 1,100 lives, according to OSHA.4 Since their in- troduction, the requirements for GFCIs have continually expanded to include additional locations.
A GFCI disconnects a circuit when it detects that the electri- cal current is not balanced between the energized conductor and the return neutral conductor. An imbalance can indicate current leakage through the body of a grounded person who accidentally contacts the energized part of the circuit. GFCI devices disconnect
quickly enough to prevent injury.
While skin offers a good deal of resistance when dry, if wet for
any reason (rain, sweat, standing in a puddle of water), the skin’s electrical resistance (measured in ohms) drops dramatically and the amount of electrical current that flows through the body increases.5
All electrical components exposed to moisture, weather, or harsh environments, whether indoors or outdoors, require a water- tight connection to eliminate or reduce the risk of electrical shocks, short circuits, and electrical fires. NEMA and IP designations apply to prevent moisture and water accumulation, in addition to out- lining protective standards for locations exposed to gases, fumes, vapors, liquids, or other agents that can have a deteriorating effect on power conductors and equipment.
GFCIs, which should be used in any indoor or outdoor area where water may come into contact with electrical products, can be placed on individual electrical power cords (in-line GFCI) or de- ployed systemically to protect an entire system from ground faults, nuisance tripping, and other hazards. It’s important to select code- compliant GFCI components from a reliable source that can ensure all parts are compatible.
Fully integrated watertight wiring systems are now offered to deliver best-in-class GFCI protection in the toughest, wettest, most abrasive work sites and industrial plants. Proper utilization of the right technologies designed for the job can help prevent the causes of many electrical-related accidents, injuries, and deaths.
Tony Quebbemann is a product manager with Molex, LLC, a glob- al electronics components company with its corporate headquarters located in Lisle, Ill. Visit www.molex.com for information.
REFERENCES
1. http://www.nfpa.org/News-and-Research/Fire-statistics-and-reports/ Research-reports/Electrical-safety/Occupational-Injuries-from-Electrical- Shock-and-Arc-Flash-Events
2. http://www.esfi.org/resource/the-2017-national-electrical-code-594 3. https://blog.dol.gov/2016/10/18/top-10-osha-citations-of-2016-a-
starting-point-for-workplace-safety/
4. https://www.osha.gov/dte/grant_materials/fy07/sh-16615-07/gfci_wir- ing_handout.pdf
5. https://www.osha.gov/dte/grant_materials/fy07/sh-16586-07/4_electri- cal_safety_participant_guide.pdf
24 Occupational Health & Safety | DECEMBER 2017
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