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.