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The problem o f harmonic d i s t o r t i o n i n low voltage d i s t r i b u t i o n systems i s a r e l a t i v e l y new issue. With t h e increased usage o f AC and DC v a r i a b l e speed d r i v e s , switching power supplies, power semiconductor c o n t r o l l e r s and o t h e r non-linear loads, harmonics now represent a major design consideration. Harmonic c u r r e n t s can cause overheating o f n e u t r a l conductors, transformers and motors. As a consequence o f harmonic currents, t h e r e l i a b i l i t y o f o v e r c u r r e n t devices may be s a c r i f i c e d . Generally, overcurrent devices a r e s i z e d based on u n d i s t o r t e d RMS l o a d currents. Depending on t h e n o n -l i n e a r i t y o f t h e load, peak c u r r e n t s may be higher o r lower than expected. The d i s t o r t e d peak c u r r e n t may cause t h e nuisance opening o r f a i l u r e t o open on c e r t a i n types o f overcurrent devices. I f t h e harmonics a r e n o t f i l t e r e d out, r e l i a b l e o v e r c u r r e n t p r o t e c t i o n can be provided only by devices which respond t o RMS c u r r e n t . RMS (Root-Mean-Square) c u r r e n t i s a measure o f t h e heat energy i n t h e c i r c u i t . Microprocessor based s o l i d s t a t e breakers and fuses a r e examples o f devices capable o f responding t o true-RMS current. This paper summarizes t h e f i n d i n g s o f numerous i n d i v i d u a l s and o v e r c u r r e n t device manufacturers and w i 11 hopeful l y he1 p t h e p l a n t engineer t o understand why overcurrent devices may open unexpectedly o r d o n ' t open a t a l l i n an overloaded c o n d i t i o n .

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Alternative input devices for computing have come to the forefront of interest of scientific teams. The idea of controlling the computer with mind has great potential. The popularization of this topic has led to a greater public interest and the creation of a market for cheap EEG devices. The article focuses on the evaluation of affordable EEG devices usage by scientific teams. Two different devices were used. The validation programs were created in the C# programming language. On a test sample composed of students, University staff and other suitably selected test subjects, the potential of affordable science devices was evaluated. In the conclusion of the article there is a discussion, as the device cannot be used for high-quality scientific work. The article also deals with the scientific teams that use the equipment for "serious" research and marks the specific errors and deficiencies that teams have committed and therefore may have the impression that the device is usable.