Pair Cartridge Fuse Reducer, Non Rejection, 60A To 30A, Boxed. Fuse reducers allow a smaller size fuse to be installed in a fuse block intended for a larger fuse. For example: a 30 amp fuse is two inches long and will not fit into a 60 amp fuse block (which is three inches betweenclips). A NO.263 reducer installed on the fuse permits it to be installed in a 60 amp fuse block. Reducers are particularly useful when equipment is being converted. Proper protection can be maintained without the expense of replacing the fuse block. Catalog numbers with the "-R" suffix (NO.263-R fit rejection (Class R) fuse blocks. Consult factory for 600 volt and Class J reducers.