The most common electric loads at enterprises, including agricultural ones, are electric motors and lighting installations. In addition, electrothermal installations and semiconductor converters of alternating current into direct current are also used. Electric motors are usually three-phase, they create higher harmonics and voltage fluctuations at the start-up. (Research purpose) The research purpose is evaluating the possibility of using data of voltage non-sinusoidality obtained from metering devices for monitoring and managing for power losses, and the reliability of electrical equipment in distribution grids. (Materials and methods) The measuring complex «Resource-UF2M», which allows the measurement and registration of electricity parameters established by GOST 32144-2013, was used to carry out the measurements. (Results and discussion) The issue of the influence of non-sinusoidal voltage on long grids of 0.4 kilovolts in Russia is relevant. In many industrially developed countries, the network is affected by powerful nonlinear loads that distort the shape of current and voltage curves in electrical grids; the connection of such loads is allowed only in compliance with the requirements for ensuring the quality of electrical energy, for this purpose appropriate corrective devices are used. At the same time, the total capacity of the newly introduced nonlinear load should not exceed 3-5 percent of the capacity of the entire power company. The opposite picture is observed in the Russian Federation, where such consumers are connected rather randomly. The issuance of technical requirements for connection in most cases has a formal character due to the lack of standard methods and mass certified devices; the rejection of filter-compensating, symmetrical, multifunctional optimizing devices leads to a deterioration in the quality of electrical energy. (Conclusions) When the power of non-linear consumers is exceeded, various problems in operation and consequences should be expected, the causes of which are not obvious. In low-voltage distribution grids supplying rural consumers with a non-linear load share of more than 25 percent, individual problems can manifest themselves immediately.