This preview shows page 1. Sign up to view the full content.
Unformatted text preview: les that are right for your current and voltage needs. Connectors are designed for specific currents and voltages so that only matching plugs and receptacles will fit together. This safeguard prevents a piece of equipment, a cord, and a power source with different voltage and current requirements from being plugged together. Standard configurations for plugs and receptacles have been established by the National Electric Manufacturers Association (NEMA). Section 8 Page 67 S A F E T Y M O D E L S TAG E 3 -- C O N T r O L L I N G H A Z A r D S : S A F E W O r K P r AC T I C E S Use locking connectors--Use locking-type attachment plugs, receptacles, and other connectors to prevent them from becoming unplugged. Use and maintain tools properly
Locking-type attachment plug. Your tools are at the heart of your craft. Tools help you do your job with a high degree of quality. Tools can do something else, too. They can cause injury or even death! You must use the right tools for the job. Proper maintenance of tools and other equipment is very important. Inadequate maintenance can cause equipment to deteriorate, creating dangerous conditions. You must take care of your tools so they can help you and not hurt you. Inspect tools before using them--Check for cracked casings, dents, missing or broken parts, and contamination (oil, moisture, dirt, corrosion). Damaged tools must be removed from service and properly tagged. These tools should not be used until they are repaired and tested. Maintain tools and equipment. Inspect your equipment before you use it. This cord has been spliced using a wire nut. Spliced cords are very dangerous! Page 68 Section 8 A n employee was climbing a metal ladder to hand an electric drill to the journeyman installer on a scaffold about 5 feet above him. When the victim reached the third rung of the ladder, he received an electrical shock that killed him. An investigation showed that the grounding prong was missing from the extension cord attached to the drill. Also, the cord's green grounding wire was, at times, contacting the energized black wire. Because of this contact with the "hot" wire, the entire length of the grounding wire and the drill's frame became energized. The drill was not double-insulated. To avoid deadly incidents like this one, take these precautions: Make certain that approved GFCIs or equipment grounding systems are used at construction sites. Use equipment that provides a permanent and continuous path to ground. Any fault current will be safely diverted along this path. Inspect electrical tools and equipment daily and remove damaged or defective equipment from use right away. Use the right tool correctly--Use tools correctly and for their intended purposes. Follow the safety instructions and operating procedures recommended by the manufacturer. When working on a circuit, use approved tools with insulated handles. However, DO NOT USE THESE TOOLS TO WORK ON ENERGIZED CIRCUITS. ALWAYS SHUT OFF AND DE-ENERGIZE CIRCUITS BEFORE BEGINNING WORK ON THEM. Protect your tools--Keep tools and cords away from heat, oil, and sharp objects. These hazards can damage insulation. If a tool or cord heats up, stop using it! Report the condition to a supervisor or instructor immediately. If equipment has been repaired, make sure that it has been tested and certified as safe before using it. Never carry a tool by the cord. Disconnect cords by pulling the plug--not the cord! Use double-insulated tools--Portable electrical tools are classified by the number of insulation barriers between the electrical conductors in the tool and the worker. The NEC permits the use of portable tools only if they have been approved by Underwriter's Laboratories (UL Listed). Equipment that has two insulation barriers and no exposed metal parts is called double-insulated. When used properly, doubleinsulated tools provide reliable shock protection without the need for a third ground. Use the right tools and equipment. Do not work on energized circuits. Don't work on energized circuits like this one! Always follow correct lock-out/tag-out procedures. Section 8 Page 69 S A F E T Y M O D E L S TAG E 3 -- C O N T r O L L I N G H A Z A r D S : S A F E W O r K P r AC T I C E S A 22-year-old male carpenter was building the wooden framework of a laundry building. He was using portable power tools. Electricity was supplied to the tools by a temporary service pole 50 feet away. The service pole had not been inspected and was not in compliance. It was also not grounded. The carpenter plugged a "homemade" cord into the service pole and then plugged a UL-approved cord into the homemade cord. His power saw was plugged into the UL-approved cord. The site was wet. Humidity was high and the carpenter was sweating. Reportedly, he was mildly shocked throughout the morning and replaced the extension cord he was using in an effort to stop the shocks. At one point, as he was climbing down a makeshift ladder constructed from a floor truss, he shifted...
View Full Document
- Spring '09