Harmful effect of harmonics is considered one of the main factors that badly affect the electricity meters’ accuracy and power quality of distribution systems. In this paper, the impact of harmonics generated by various household appliances has been investigated. Household appliances have been divided into four groups according to the similarity of their current and voltage waveforms. The appliances have been collected together according to the reason of the year and time to analyze their waveform. Experimental measurements have been performed using a standard CALMET-TE30 three-phase power quality analyzer. Measurement uncertainty calculations have been taken into consideration to acquire the actual measurement results. The waveforms of these results have been precisely plotted using a specially designed MATLAB program.