Low amperage, E‑rated medium voltage fuses are general purpose current limiting fuses. The E rating defines the melting time current characteristic of the fuse and permits electrical interchangeability of fuses with the same E rating. For a general purpose fuse to have an E rating the following condition must be met. The current responsive element shall melt in 300 seconds at rms, current within the range of 200% to 240% of the continuous current rating of the fuse, fuse refill or link. (For fuses rated 100E or less). Bussman low amperage, E rated fuses are designed to provide primary protection for potential, small services and control transformers. These fuses offer a high level of fault current interruption in a self‑contained non‑venting package, which can be mounted indoors or in an enclosure.