Aurora were appointed by Edward Dewhurst to carry out a detailed protection coordination study for a planned upgrade of BAEs facility in Samlesbury. Aurora first developed a model of the power system in ETAP, before running a series of short circuit studies for the normal and emergency operating condition, to determine the fault current range of the system. A series of protection coordination studies were undertaken to confirm satisfactory discrimination in the electrical system for all normal and emergency operating conditions. Due to the presence of a large number of fuses on the site, Aurora undertook in depth review of the fuse-fuse coordination by comparing the pre-arcing and total clearing I2T characteristics of the fuses, to ensure that the system operated satisfactorily.