This handbook covers the code of practice in protection circuitry including standard lead and device numbers, mode of connections at terminal strips, colour codes in multicore cables, dos and donts in execution. Anyone interested in protective relays, power system protection, substations, industrial electrical systems, or relay testing can join this course. "This course contains the use of artificial intelligence. They are intended to quickly identify a fault and isolate it so the balance of the system continue to run under normal conditions. This course is designed to provide a practical and theoretical foundation in. The handbook for protection engineers includes guidelines on protective circuitry, protective relay principles, and testing procedures for switchgear and relays.