IEC 61000-4-13 pertains to immunity to harmonics and interharmonics distortion of AC mains supply up to 16 A per phase at frequencies including 50 Hz and 60 Hz. This test is commonly conducted with a programmable supply or source with appropriate added functionality to allow for EMI or power quality tests. The goal of the test is to asses the impact the distorted power has on the equipment or device under test. Related common power quality immunity tests include voltage fluctuations, AC/DC dips & interruptions, and variations in power frequency.