Insulation resistance testers are devices used to measure the resistance of electrical insulation in cables, motors, and other equipment. They help ensure that insulation is intact and functioning properly, preventing electrical leaks and potential hazards. By applying a high voltage, these testers can identify weak spots in insulation that may lead to failures. These testers are essential for maintenance in various industries, including construction and manufacturing. Regular testing can help extend the lifespan of electrical systems and improve safety. Common standards for testing include those set by organizations like IEEE and IEC, which provide guidelines for proper usage and interpretation of results.