With the development of technology, there is an increase in the industry of sensitive devices which work is dependent on parameters of electricity from which they are supplied. This aspect is especially important for example in hospitals, where health and human life often depend on the correct work of electronics devices. The article presents – on the selected practical example – parameters describing the electricity supplying the hospital facility. In that hospital the incorrectly operation of the magnetic resonance has been observed. The analyzed facility is powered from the medium voltage network via its own 15/0,4 kV transformer station. Based on changes in recorded waveforms of physical quantities in time, it was noticed that the loads installed there significantly impact on the quality of the electricity which are supplied. One of the figures presents value of the waveform of the total harmonic distortion coefficient of the voltage, which is dependent on value of the load’s current. Based on the recorded parameters describing the quality of electricity supplying the prospected hospital, possible technical solutions have been proposed. They can directly contribute to the elimination of interference, and thus guarantee the proper work of the equipment set there.