Bussmann series Fusetron cartridge fuses are 23% more energy-efficient and offer the ideal time delay performance. Their dual-element feature allows closer sizing to load for excellent protection of motors and transformers. These Class RK5 fuses with a 200 kA interrupting rating can be used in a broad range of applications. When sized correctly, they help protect motors from burnout caused by overloads or single phasing. The time delay feature allows the initial startup current surge for typical motors to pass, but opens prior to motor burnout when longer, dangerous overloads are present. In addition, the dual-element design opens in as little as 0.004 secs if the fuse experiences short circuit conditions. All fuses are UL listed Class R (IR: 200 kA). Groove in end cap or notch in knife blade permit the fuse to be used in only Class H, Class K or Class R fuse blocks.