Current-Limiting Fuse Application Guidelines

Utilities have had experiences where distribution line equipment has failed catastrophically in the field. This typically happens when more fault energy is let through to the failed unit than its enclosure can withstand before a protective device interrupts the energy source. Such catastrophic failure can result in personal injury and/or damage to the surrounding environment. Various agencies have completed tests and published papers on the subject of energy withstand capability but few standards or guidelines have emerged for utility use.

This project aimed at gathering published material and acquiring information about utility practices through surveys with the goal of developing current limiting fuse application guidelines.


With the above project objective in mind, the following tasks were completed and summarized within this report:

  • Standards and requirements for transformer and capacitor withstand ratings were examined
  • DSTAR utility members and a few other utilities were surveyed to gather information about prevailing practices and guidelines related to current limiting fuse applications
  • Catalog data and comments were acquired from equipment manufacturers relating to equipment withstand ratings and current limiting fuse application
  • Results were summarized from the above exploratory efforts resulting in suggested documented guidelines

Report Overview

The final report is a 57-page document that:

  • Provides a review of IEEE standards and published technical papers.
  • Presents data and suggestions from manufacturers
  • Profiles current utility practices
  • Provides guidelines for current limiting fuse applications
  • Includes summary of utility and manufacturer survey responses


This study was conducted in: P12-7