The differences between static (second and third generation) and digital relays (fourth generation) were listed in Sections 9.3.2.2 through 9.3.2.4, respectively. As it was mentioned, the earlier versions of static relays are not equipped with automatic self-test features therefore they may require more attention than the digital relays having self-test features. The inspection and maintenance of static and digital relays can be addressed under each relay type. The following is a guide for inspecting and testing static relays.