How do you test a safety fuse?

• A. Average burn time from a 3 foot piece
• B. Measure burn rate per inch
• C. Use a fuse tester device
• D. Light and observe the fuse for signs of ignition

Answer: (A)

Testing a safety fuse means confirming it burns at a predictable, spec-worthy rate. The way to do this is by using a fixed reference length—commonly a measured piece around three feet—and timing how long it takes to burn from start to finish. That single, defined measurement gives you the average burn time for that length, which you can compare to the fuse’s published specification. If the burn time matches or stays within tolerance, the fuse is considered acceptable for use; if it doesn’t, the fuse may be unreliable and should be rejected. This method is practical and repeatable because it directly ties a concrete time to a known length, making it easy to compare lots of fuses consistently. Using a fuse tester device may not reflect real-world burn behavior, lighting and watching for ignition signs is unsafe and unreliable, and calculating burn rate per inch without a standard length test doesn’t provide a solid, comparable benchmark.