Figure 1-17. - Minimum safe distance for working around energized conductors.
The primary killer of riggers and those persons handling loads is electrocution caused by the contact of the boom, load line, or load of a crane with electric power lines. When working with or around cranes that are within a boom's length of any power line, you must ensure that the power to that section of line is secured. If for some reason this cannot be accomplished, a competent signalman must be stationed at all times within view of the operator to warn him when any part of the machine or its load is approaching the minimum safe distance from the power line (fig. 1-17). You must also exercise caution when working near overhead lines that have long spans, as they tend to swing laterally because of the wind, and accidental contact could occur.
The safe working loads of hoisting equipment apply only to freely suspended loads on plumb hoist lines. If the hoist line is not plumb at all times when handling loads, then additional side loads will endanger the stability of the equipment. In circumstances such as this, structural failures can result without any warning (fig. 1-18).
Never use kinked or damaged slings or hoist wire ropes. To provide maximum operating efficiency and safety, you should give all slings and fittings thorough periodic inspections as well as daily inspections for signs of wear and abrasion, broken wires, worn or cracked fittings, loose seizing and splices, kinking, crushing, flattening, and corrosion. Special care should be taken in inspecting the areas around thimbles and fittings.
Figure 1-18. - Incorrect lifting procedures.Continue Reading