Noise on Residential Power Distribution Circuits

This paper presents electromagnetic noise measurements on power distribution circuits in the frequency range of 5-100 kHz. Since this noise is due primarily to appliances such as universal motors, light dimmers, television receivers, and certain switching power supplies located on the secondary side of the distribution transformer, the noise varies dramatically with time as these appliances are turned on and off. Measurements of the noise inserted into the distribution circuit by several representative appliances are presented. The noise measurement technique itself, as well as the resulting measurements, are described. Background noise which is present in the absence of such appliances was also measured. These noise measurements are important for the design of communications systems, such as distribution-line carrier, which operate in the 5-20 kHz region and use the distribution line as a communications medium.