This standard gives the rules for power resistors (for example, braking, heating, snubber and filter) used in the power and auxiliary circuits on board rolling stock irrespective of the circuit and the type of vehicle where they are used. These resistors are generally of open construction and are used in polluted areas. The construction consists of resistor elements of grids, plates, strips, ribbons or wires. This standard states - the characteristics of the resistors; - the service conditions with which the power resistors have to comply; - the tests intended for confirming that these conditions have been met and the methods to be adopted for these tests;