Recently, however, the applications of direct current are growing in terms of both their number as well as their diversity.
One important group of direct current applications are systems for providing uninterruptible power supply (UPS) to safety-critical equipment, such as that used in operating theatres.
At present, direct current is often used in lighting applications.
In addition, mass production of devices and appliances designed for use by people with no qualifications, including children, justifies the undertaking of a wide scope of studies on direct current shocks.
Due to the lower number of devices and systems powered with direct current (as compared to alternating current) under voltages capable of producing adverse effects, the direct current shock incidents are much less frequent than those involving alternating currents, and they constitute only a few percent of the overall number of electric shock accidents .