Water Well Journal
Issue link: https://read.dmtmag.com/i/655200
C ontacting energized power lines can result in fatal elec- trocutions, if not serious burns or damaged equipment. Contact with overhead power lines is the most com- mon cause of deaths involving cranes or other high-reaching equipment. Reviewing causes of crane-related deaths in construction from 1992-2006, electrocutions accounted for almost one- third (32%) of crane-related fatalities. Half of all the electro- cutions occurred when the crane boom or cable contacted an overhead power line. The rest involved a power line coming into contact with parts of the crane (McCann et al. 2008). Some years ago, the Occupational Safety and Health Ad- ministration revised its requirements for working around over- head power lines. These revisions were contained in OSHA's Final Rule for Cranes and Derricks in Construction (29 CFR Part 1926) and published in the Federal Register in 2010. OSHA determined a more systematic, proactive approach to preventing contact with power lines was needed. We will discuss these measures to prevent contact with an overhead power line, as well as what to do if contact is made. Assess the Hazard Before beginning operations, a hazard assessment inside the work zone must be performed. The hazard assessment must: • Identify the work zone and assess it for power lines. Deter- mine how close the crane or any high-reaching equipment could get to the lines. The employer has an option of as- sessing the area the entire 360 degrees around the crane or assessing a more limited area. • If the assessment shows the crane could get closer than 20 feet for power lines up to 350 kilovolts (kV) or 50 feet for lines over 350 kV—then requirements for additional action are triggered. Eliminate the Hazard If operations involving cranes or drilling rigs will be per- formed near overhead power lines and the minimum clearance distances specified by OSHA, shown later, cannot be main- tained, the first option is to de-energize and visibly ground the power lines. By eliminating the source, the hazard of elec- trocution is eliminated. De-energizing the lines has to be coordinated with the utility company or owner of the line. The line owner may need several weeks to comply with the request, so the work should be planned appropriately. Only authorized personnel may de-energize a power line. All power lines shall be presumed energized unless the utility owner or operator confirms the power line has been, and continues to be, de-energized and visibly grounded at the worksite. If the power line cannot be de-energized for the duration of the work, another option is to move the line the minimum clearance distance it can be maintained. Like de-energizing the line, only the company who owns the line may move it. Again, the line owner may need several weeks to comply with the request. Keep Your Distance OSHA's requirements regarding working near overhead power lines with cranes and other high-reaching equipment are straightforward. For lines 50 kV or less, the operator must keep all parts of the crane or other equipment at least 10 feet away from all power lines. For lifting equipment, this also includes any load being carried. This minimum clearance distance is a buffer zone that must be kept between the equipment and overhead lines. In other words, minimum clearance is the minimum distance that is allowed from any part of a crane or other high-reaching equipment to an overhead power line. If the lines have a voltage higher than 50 kV, the line's minimum clearance distance must be increased according to Table A of 29 CFR 1926.1408, Power Line Safety— Equipment Operations (see Figure 1). Distribution lines are typically 50 kV or less, whereas transmission lines are typically higher than 50 kV. Distribu- tion lines are the most common lines used by utilities. To de- termine the voltage rating of the power line, contact the utility company. If you still cannot determine the voltage range, you must keep at least 45 feet away. Preventing Encroachment or Electrocution If any part of the crane, equipment, or load (including rig- ging and lifting accessories)—while operating up to the max- imum working radius in the work zone—could get closer than the minimum approach distance permitted in Table A, a num- ber of precautions should be followed. Conduct a planning meeting with the operator and other workers who will be in the area of the equipment or the load SAFETY MATTERS SAFETY AROUND POWER LINES Does your crew know how to prevent electrocutions from contact with overhead power lines? SAFETY continues on page 34 JEROME E. SPEAR WWJ April 2016 33 Twitter @WaterWellJournl