The Littelfuse Energy Storage Rack (ESR) series of fuses is designed specifically to protect battery racks in energy storage systems, inverters, and many other dc applications. The 1500 V dc high-speed square body fuse is extremely fast-acting to respond quickly to a range of fault currents to safeguard the battery module or other devices. This Class aBat partial range fuse has superior short circuit protection and a low minimum breaking capacity (MBC)—from 300 % or 3 times the fuse’s rated current to 175 kA (250 kA self-certified)—to cover a range of over currents that traditional high-speed partial range fuses do not protect against. The ESR fuse safely interrupts most faults in a battery storage system to avoid catastrophic failures and costly shutdowns.