SL fuses for residential motor circuits in kitchens, workshops, garages, utility rooms or any circuit with motors, relays or solenoids. The rejection base threads prevent a larger amp fuse from being used. Example: A 30 amp fuse cannot be installed in a 20 amp receptacle because of the different sized threads. Medium-duty fuse. These fuses thread into fuse receptacles. Threaded fuse type: Rejection Base (porcelain threads). Not interchangeable with Edison Base (brass threads) type. Medium-duty (SL) category plug fuse. The medium-duty fuse (SL) has a time-delay feature for use on motor circuits. Plug fuses are rated for a maximum of 125Vac. SL three pack (PK3) version (blister pack). Plug fuses are often used in residential and industrial branch circuit and motor protection. Fuses are used to protect furnace blower motors, pumps, power tools, garage door openers, etc. Motor protection fuses are usually used in conjunction with branch circuit protection. The fuse is often located in a box cover unit. Plug fuses provide a compact and inexpensive method to prevent damage to electrical motors. They help reduce downtime and lower maintenance costs by opening the circuit when a dangerous overload is present. When used for residential branch circuit protection, fuses are typically located in the main fuse panel..The EATON's Cooper Bussmann brand is the industry standard for circuit protection on more than 50,000 SKUs of electrical and electronic fuses, fuse holders, power distribution blocks as well as engineering, training and testing services. EATON's Cooper Bussmann is the leading source of circuit protection solutions in the global marketplace. Its solutions are listed for use around the world including meeting agency requirements with UL、CE、CSA、IEC、BS、VDE、SEMKO, and JIS.