Plug Fuse, Indicating, 5A, W Series, Fast Acting, PK 4

Fast-acting plug fuses are Type W fuses for protecting lighting, heating, and other residential and industrial circuits without motors. They open within seconds of being exposed to overloads and short circuits. Also called fast-blow plug fuses, they are highly sensitive to changes in current flow and don't tolerate temporary overload currents or power surges. They have a brass-threaded Edison base that screws directly into a fuse receptacle.

Plug fuses are screw-in fuses for protecting against overcurrent in residential and industrial branch circuits as well as motor circuits. They are commonly found in a box cover unit or main fuse panel and are used to prevent damage to equipment such as pumps, power tools, and HVAC blowers. These plug fuses are color-coded by voltage to help prevent installation of a mismatched fuse. They have a window that reveals whether the fuse element has blown.