Safety Engineering: High Voltage and Current Conditions

IE‐614 Midterm Exam Safety Engineering Spring 2012 1. Electric safety involves controlling 2 main hazards through one hazard is only evident under high voltage and current conditions. List them and describe some ways you can control the hazards. There are two main hazards of electricity are: electrical shock and electrical arcflash/blast. OSHA statistics show that several hundred deaths occur annually as a result of electrical shock. Over one-half of these deaths are the result of contact with low voltage, primarily 120-volts. Residential, commercial, industrial, farm, and utility accidents are included in these statistics. NIOSH statistics show that electrical contact results in 4,000 non-disabling and 3,600 disabling injuries annually in the United States. Many of the electrical shock accidents that occur in commercial and industrial facilities are the result of contact with 277-volts. This is due to the extensive use of 277-volt fluorescent lighting. Employees generally perform maintenance on these light fixtures without performing a proper lockout/tagout of the circuit. Studies also show that 10-15 employees are hospitalized every day with arc-flash burns, which are often catastrophic to the victims physically, psychologically, and financially. In reality, the hazards associated with the use of electricity are real and can affect anyone. Electrical shock - Electrical shock occurs when a person’s body completes the current path between two energized conductors of an electrical circuit or between an energized conductor and a grounded surface or object. Essentially, when there is a difference in potential from one part of the body to another current will flow. The effects of an electrical shock can vary from a slight tingle to immediate cardiac arrest. The severity depends on several factors: body resistance wet or dry skin are major factors of resistance, circuit voltage, amount of current flowing through the body, current path through the body, area of