Banning of lead solder alloys in Japan and in the EU has led to the application of pure tin and various tin alloy solders in the electronic production both surface mounted technology (resistors, capacitors, other passive elements and integrated circuits) and through hole circuits and other larger elements. In addition the legs of the components and other contact surfaces can get often a tin surface. From these tin surfaces are growing many one or multi crystal formations, which are named whiskers and are much thinner than the human hair. These whiskers are a major reliability problem for the highly integrated electronics. During the research I will looking for incidents caused by whiskers and I will examine the importance of the errors caused by them. Furthermore I will search the answer for the reason of their growth. In my thesis I will specially focus on current-carrying conductors. For that I have developed my own experiment and tests. During the test the circuit boards were placed in a HT chamber for 3000 hours and they were loaded with different currents. The reason why this topic deserves high attention is because there is a current load on the solders in the majority of cases.