A properly installed and clean connector should not lose more than 0. If a connector is chipped, scratched, or not seated correctly, the light path is disrupted, increasing the overall system. To be able to judge whether a fiber optic cable plant is good, one does a insertion loss test with a light source and power meter and compares that to an estimate of what is a reasonable loss for that cable plant. Fiber optic testing of a newly installed system not only verifies that the system meets its design requirements, but also creates a performance baseline for all future testing and troubleshooting of t at system. Corning recommends that all fiber optic systems be tested to a minimum set. Insertion loss, also known as attenuation, is the loss of optical power that occurs when light passes through a fiber optic connector.