The first dc helicity injection is tried applying a voltage between two parallel plates, and effects on plasma performance are studied in the reversed field pinch plasma. The injected current is nearly proportional to the applied voltage VH with a small offset-induced voltage ( approximately -30 V), and a transient increase in the toroidal flux and a decrease in the poloidal field (plasma takes the more relaxed state) is found near the injection port, regardless of the polarity of VH. The induced voltage measured as a function of the insertion depth shows the presence of high-energy electrons.