IEC 60077-2:2017 provides general rules for all electrotechnical components installed in power circuits, auxiliary circuits, control and indicating circuits, etc., on railway rolling stock. The purpose of this document is to adapt the general rules given in IEC 60077-1 to all electrotechnical components for rolling stock, in order to obtain uniformity of requirements and tests for the corresponding range of components. This new edition includes the following main technical changes with regard to the previous edition: short circuit breaking capacity; rated short-time withstand current; critical currents range; specification of climatic conditions. This standard is to be read in conjunction with IECA 60077-1:2017.