When the interval in which relays fail (either complete failure, or deviation of settings), it is a certain moment better and more cost-effective to replace the whole population of this type of relay. To determine the best solution (increasing inspection frequency or replacement of the whole population) the Risk-Based Asset Management (RBAM) methodology is used, as described in chapter 3. The input for these analyses are the component quality documents and the fail codes (especially the fail rate of the components). When in the future the certain fail rates increase, the analyses can easily be repeated, and in this way the best moment can be determined for replacement of the complete population of a certain type of relay.