Clayton is explaining the issue of electrical noise in a system, due to the added components. Electronics can create electrical noise, such as unwanted signals and fluctuations in current or voltage. Such noise also exists on the DC side of a solar system. This is typically not a problem. However, with the advent of DC optimizers, the noise levels increase significantly and start interfering with an important safety measure: the Arc Fault detection and circuit interruption, also known as AFCI. With noise, AFCI is not able to identify real arcs or to distinguish them from the noise. With many Module Level devices, an AFCI algorithm has to deal with a lot more noise. All this noise increases the likelihood of nuisance tripping, which negatively impacts the system’s reliability and operational cost, as well as the ROI. Or even worse, a real arc might not be detected, and cause a fire.