MERSEN fuse reducers allow the use of lower rated fuses in existing equipment having clips with higher ampere ratings. The use of closer rated time delay fuses can improve circuit protection. For example, renewable or one time fuses feeding a motor can be replaced with fuses sized closer to the motor nameplate current. Non-rejection reducers will allow class H, K or R fuses to fit class H or K clips. Rejection-type reducers will allow only class R fuses to fit class R clips or only class J fuses to fit class J clips. Class J fuse reducers are not for bolt on applications.