During fuse testing, test probes should contact which parts of the fuses?

During fuse testing, test probes should contact which parts of the fuses?

• A. The Metal End Caps of Ferrule Fuses and the Blades on Knife‑Blade Fuses
• B. The Fuse Body Only
• C. The Fuse Packaging
• D. The Mounting Lugs Only

Answer: (A)

The test measures the fuse element by applying the test across its actual current-carrying terminals. For ferrule fuses, those terminals are the metal end caps; for knife-blade fuses, they are the blades. Probing the fuse body, packaging, or mounting lugs won’t put the test current through the fuse element, and could give an inaccurate reading or create unsafe conditions. By placing the probes on the end caps or on the blades, you’re testing the true path of the fuse and can see whether the element is conducting normally or has opened.

The test measures the fuse element by applying the test across its actual current-carrying terminals. For ferrule fuses, those terminals are the metal end caps; for knife-blade fuses, they are the blades. Probing the fuse body, packaging, or mounting lugs won’t put the test current through the fuse element, and could give an inaccurate reading or create unsafe conditions. By placing the probes on the end caps or on the blades, you’re testing the true path of the fuse and can see whether the element is conducting normally or has opened.